BioMechatronics Laboratory Publications

Journal Articles | Revues avec Comité de lecture
  1. O. Wilz, B. Kent, B. Sainsbury, and C. Rossa - Multiobjective trajectory tracking of a flexible tool during robotic percutaneous nephrolithotomy. IEEE Robotics and Automation Letters, in press, 2021. Also, selected for presentation at IEEE Intenational Conference on Intelligent Robots and Systems, Prague, Czech Republic, 2021 10.1109/LRA.2021.3102946 BibTeX

    @Article{Wilz2021RAL,
    author={O. Wilz, B. Kent, B. Sainsbury, and C. Rossa},
    journal={Robotics and Automation Letters},
    title={Multiobjective trajectory tracking of a flexible tool during robotic percutaneous nephrolithotomy},
    year={2021},
    volume = {4},
    issue={4},
    pages = {8110-8117},
    issn = {2377-3766},
    doi = {10.1109/LRA.2021.3102946},
    url = {https://ieeexplore.ieee.org/document/9508860?source=authoralert},
    }

    Abstract

    Percutaneous Nephrolithotomy (PCNL) is the leading intervention for removing large or irregularly shaped kidney stones. It involves gaining access to the kidney through a small incision in the patient’s back, through which a nephroscope is steered towards the stones. Despite decades of clinical prevalence, PCNL remains a complex procedure to learn and perform, sometimes requiring several attempts to gain kidney access, leading to a variety of complications. This paper proposes to use robotic assistance to steer a flexible nephroscope during PCNL to concurrently improve accuracy and reduce the risk of tissue damage. The nephroscope is modelled as a cantilever beam fixed to the robot’s end-effector. Under the assumption that an optimal tooltip path exists, Non-dominated Sorting Genetic AlgorithmII is implemented to determine the end-effector position and orientation so that the tooltip follows the path while minimizing four objective functions, i.e., tissue compression, variations in the tool’s strain energy, changes in end-effector position, and tooltip error. Data collected through experiments performed on ex-vivo porcine tissue show that the path tracking error was on average 2.03 mm. The results confirm the accuracy of the model in 2 dimensions and suggest that the multiobjective optimizer returned adequate solutions that minimized 4 different cost functions, altogether allowing the robot to effectively follow the predefined path.

  2. B. Kent, and C. Rossa - Development of a tissue discrimination electrode embedded surgical needle using bibrotactile feedback derived from electric impedance spectroscopy. in Medical & Biological Eng & Computing, in press, 2021. BibTeX

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    Abstract

    Some tumours may not be detected by ultrasound during biopsy, but recent evidence has shown that different tissues can be discerned by electric impedance. This paper explores the application of vibrotactile feedback in an electrode embedded needle to help classify tissue during fine-needle aspiration biopsy from bioimpedance measurements. The process uses electric impedance spectroscopy from 10 Hz to 349 kHz to fit the double dispersion Cole model through the Newton-Raphson algorithm. A Naive Bayes classifier is then used on the equivalent circuit parameters to estimate the tissue at the needle tip. The method is validated through a series of experiments and user trials. The results show that the vibrotactile feedback is able to help the operator in determining the tissue the needle is in, suggesting that this may prove to be a useful supplement to the standard procedure used today.

  3. R. Tan, and C. Rossa - Electrical Impedance Tomography for Robot-Aided Internal Radiation Therapy. Frontiers in Bioengineering and Biotechnology, vol. 9, pp. 527, 2021, 10.3389/fbioe.2021.698038 (pdf) BibTeX

    @Article{KentB,
    author={R. Tan, and C. Rossa},
    journal={Frontiers in Bioengineering and Biotechnology},
    title={Electrical impedance tomography for robot-aided internal radiation therapy.},
    year={2021},
    volume = {9},
    pages = {527},
    issn = {2296-4185},
    doi = {10.3389/fbioe.2021.698038},
    url = {https://www.frontiersin.org/article/10.3389/fbioe.2021.698038},
    }

    Abstract

    High dose rate brachytherapy (HDR) is an internal based radiation treatment for prostate cancer. The treatment can deliver radiation to the site of dominant tumour growth within the prostate. Imaging methods to delineate the dominant tumour are imperative to ensure the maximum success of HDR. This paper investigates the feasibility of using electrical impedance tomography (EIT) as the main imaging modality during robot-aided internal radiation therapy. A procedure utilizing brachytherapy needles in order to perform EIT for the purpose of robot-aided prostate cancer imaging is proposed. It is known that cancerous tissue exhibits different conductivity than healthy tissue. Using this information, it is hypothesized that a conductivity map of the tissue can be used to locate and delineate cancerous nodules via EIT. Multiple experiments were conducted using 8 brachytherapy needle electrodes. Observations indicate that the imaging procedure is able to observe differences in tissue conductivity in a setting that approximates transperineal HDR and confirm that brachytherapy needles can be used as electrodes for this purpose. The needles can access the tissue at a specific depth that traditional EIT surface electrodes cannot. The results indicate the feasibility of using brachytherapy needles for EIT for the purpose internal16radiation therapy

  4. B. Kent, and C. Rossa - Electric impedance spectroscopy feature extraction for tissue classification with electrode embedded surgical needles through a modified forward stepwise method. Computers in Biology and Medicine, pp 104522, 2021, 10.1016/j.compbiomed.2021.104522 (pdf) BibTeX

    @Article{KentB,
    author={B. Kent, and C. Rossa},
    journal={Computers in Biology and Medicine},
    title={Electric impedance spectroscopy feature extraction for tissue classification with electrode embedded surgical needles through a modified forward stepwise method.},
    year={2021},
    volume = {135},
    pages = {104522},
    issn = {0010-4825},
    doi = {https://doi.org/10.1016/j.compbiomed.2021.104522},
    url = {https://www.sciencedirect.com/science/article/pii/S0010482521003164},
    }

    Abstract

    There has been a growing interest in developing electric impedance sensing surgical tools for tissue identification during surgery. A key facet of this development is identifying distinct features that can be used to identify tissues from one another. This paper explores several feature extraction techniques and classification methods applied to electric impedance data. Furthermore, a modified forward stepwise method is proposed. The method introduces a scoring metric to help select features to add to the model, that is based off of the coefficient of variation and overlapping index from the feature’s probability density functions for each of the classes. The proposed and existing methods were applied to spectral data measured at 23 frequencies, from 132 samples across 6 different tissues including ex-vivo bovine kidney, liver and muscle, poultry liver, as well as freshly excised canine testicle and ovary samples. These methods were able to successfully find impedance spectra features for the investigated biological tissues. The best predictive accuracy was with Boruta feature extraction and a Random Forest classifier but without signifigantly reducing the number of features in the classifier model. The proposed method was able to reduce the number of features in the model to an average of 5.8 features for all tested classifiers. These methods may have use in finding features to discriminate other tissue types, possibly to aid in targeting lesions in minimally invasive cancer treatment surgeries.

  5. O. Wilz, B. Sainsbury, and C. Rossa - Constrained haptic-guided shared control for collaborative human-robot percutaneous nephrolithotomy training. Mechatronics (Elsevier), A journal of IFAC, the International Federation of Automatic Control , in press, 2021, 10.1016/j.mechatronics.2021.102528 (pdf) BibTeX

    @Article{Wilz2021,
    author={O. Wilz and B. Sainsbury and C. Rossa},
    journal={Mechatronics},
    title={Constrained haptic-guided shared control for collaborative human-robot percutaneous nephrolithotomy training},
    year={2021},
    volume = {75},
    pages = {102528},
    issn = {0957-4158},
    doi = {https://doi.org/10.1016/j.mechatronics.2021.102528},
    url = {https://www.sciencedirect.com/science/article/pii/S0957415821000301},
    }

    Abstract

    Percutaneous nephrolithotomy is a procedure used to treat patients with large or irregularly shaped kidney stones. Surgical instruments are inserted through a small incision to access the kidney and remove the calculi. Surgeons who have less experience with the procedure manifest significantly higher rates of complications due to the procedure's steep learning curve. This issue is further exacerbated by a lack of training opportunities in clinical settings.
    This paper introduces a teleoperative framework that can provide training to surgeons as well as assistance during procedures, based on two main components. Firstly, a type of constrained inverse kinematics that decouples the tooltip position from its orientation using a remote centre of motion, and incorporates the joint limits analytically. This reduces the workload of the procedure by having the surgeon control only the tooltip position rather than the position and the orientation while preventing the inverse kinematics from returning joint angels outside of the robot's abilities. This kinematic framework also allows a threedegrees-of-freedom haptic device to control a six-degrees-of-freedom manipulator. Secondly, haptic feedback is provided to help guide and teach the surgeon during the procedure. Haptic feedback allows the surgeon to remain in full control during the procedure while still receiving haptic cues and assistance. Experimental results indicate that the haptic cues improved user's accuracy, and they had shorter and smoother paths. This leads to a shorter procedure time overall. The results also indicate that the haptic assistance helped teach users the ideal trajectory of the procedure and that users who were taught with haptic feedback performed better than those who never experienced any haptic feedback.

  6. C. McDermott, M. Lacki, B. Sainsbury, J. Henry, M. Filippov, and C. Rossa - Sonographic diagnosis of COVID-19: A review of image processing for lung ultrasound. Frontiers in Big Data, section Medicine and Public Health , in press, 2021, 10.3389/fdata.2021.612561 BibTeX

    @Article{McDermott2021,
    author={C. McDermott and M. Lacki and B. Sainsbury and J. Henry and M. Filippov and C. Rossa},
    journal={Frontiers in Big Data, section Medicine and Public Health},
    title={Sonographic diagnosis of COVID-19: A review of image processing for lung ultrasound},
    year={2021},
    volume={},
    pages={},
    doi={},
    ISSN={2624-909X},
    }

    Abstract

    The sustained increase in new cases of COVID-19 across the world and potential for subsequent outbreaks call for new tools to assist health professionals with early diagnosis and patient monitoring. Growing evidence around the world is showing that lung ultrasound examination can detect manifestations of COVID-19 infection. Ultrasound imaging has several characteristics that make it ideally suited for routine use: small hand-held systems can be contained inside a protective sheath, making it easier to disinfect than X-ray or computed tomography equipment; lung ultrasound allows triage of patients in long term care homes, tents or other areas outside of the hospital where other imaging modalities are not available; and it can determine lung involvement during the early phases of the disease and monitor affected patients at bedside on a daily basis. However, some challenges still remain with routine use of lung ultrasound. Namely, current examination practices and image interpretation are quite challenging, especially for unspecialised personnel.
    This paper reviews how lung ultrasound (LUS) imaging can be used for COVID-19 diagnosis and explores different image processing methods that have the potential to detect manifestations of COVID-19 in LUS images. Then, the paper reviews how general lung ultrasound examinations are performed before addressing how COVID-19 manifests itself in the images. This will provide the basis to study contemporary methods for both segmentation and classification of lung ultrasound images. The paper concludes with a discussion regarding practical considerations of lung ultrasound image processing use and draws parallels between different methods to allow researchers to decide which particular method may be best considering their needs. With the deficit of trained sonographers who are working to diagnose the thousands of people afflicted byCOVID-19, a partially or totally automated lung ultrasound detection and diagnosis tool would be a major asset to fight the pandemic at the front lines.

  7. B. DeBoon, S. Nokleby, and C. Rossa - Invited paper - Multi-objective gain optimiser for a multi-input active disturbance rejection controller: Application to series elastic actuators. Control Engineering Practice, Special section Emerging Leaders in Control Engineering Practice, vol 109, pp 104733, 2021, 10.1016/j.conengprac.2021.104733 (pdf) BibTeX

    @Article{DeBoon2021,
    author={B. DeBoon and S. Nokleby and C. Rossa},
    journal={Control Engineering Practice},
    title={Multi-Objective Gain Optimiser for a Multi-Input Active Disturbance Rejection Controller: Application to Series Elastic Actuators},
    year={2021},
    volume={109},
    pages={104733},
    doi={10.1016/j.conengprac.2021.104733},
    ISSN={0967-0661},
    }

    Abstract

    Series elastic actuators (SEA) have been gaining increasing popularity as a mechanical drive in contemporary force-controlled robotic manipulators thanks to their ability to infer the applied torque from measurements of the elastic element's deflection. Accurate deflection control is crucial to achieve a desired output torque and, therefore, unmodelled dynamics and dynamic loads can severely compromise force fidelity. Multi-input active disturbance rejection controllers (ADRC) have the ability to estimate such disturbances affecting the plant behaviour and cancel them via an appropriate feedback controller. Thus, they offer a promising control architecture for SEA. ADRC, however, can have upwards of eight tuning parameters for each controlled state. Tuning the controller becomes quite challenging, especially in the context of multi-input, multi-objective control.
    This paper tackles the problem of ADRC tuning as a multi-parametric and multi-objective optimisation approach. An ADRC is developed to regulate the output torque of a multi-input hybrid motor-brake-clutch SEA. The controller has a total of 22 tunable parameters. Point dominance-based nondominated sorting genetic algorithm is used to find the optimal control gains, first considering nine individual control objectives, and then in the context of multi-objective. {The algorithm provides a set of potential solutions that highlight the treadoffs between the control objectives. It is up to the discretion of the designer to select the appropriate solution that best suits a given application}. The approach is validated experimentally and the results are compared with a simulated model. Experimental results confirm the suitability of the proposed approach for single and multiple control objectives in a variety of experimental scenarios and show good agreement with the analytical model.

  8. C. Rossa, M. Najafi, M. Tavakoli, and K. Adams - Robotic rehabilitation and assistance for individuals with movement disorders based on a kinematic model of the upper limb. IEEE Transactions on Medical Robotics and Bionics, vol. 3, no. 1, pp. 190-203, 2021, 10.1109/TMRB.2021.3050512 BibTeX

    @Article{Rossa2020,
    author={C. Rossa and M. Najafi and M. Tavakoli and K. Adams},
    journal={IEEE Transactions on Medical Robotics and Bionics},
    title={Robotic rehabilitation and assistance for individuals with movement disorders based on a kinematic model of the upper limb},
    year={2020},
    volume={3},
    pages={190-203},
    issue={1},
    doi={10.1109/TMRB.2021.3050512},
    ISSN={2576-3202},
    }

    Abstract

    Design and development of robotic-assistance must consider the abilities of individuals with disabilities. In this paper, a 8-DOF kinematic model of the upper limb complex is derived to valuate the reachable workspace of the arm during interaction with a planar robot and to serve as the basis for rehabilitation strategies and assistive robotics. Through inverse differential kinematics and by taking account the physical limits of each arm joint, the model determines workspaces where the individual is able to perform tasks and those regions where robotic assistance is required. Next, a learning-from-demonstration strategy via a nonparametric potential field function is derived to teach the robot the required assistance based on demonstrations of functional tasks. The paper investigates two applications. First, in the context of rehabilitation, robotic assistance is only provided if the individual is required to move her arm in regions that are not reachable via voluntary motion. Second, in the context of assistive robotics, the demonstrated trajectory is scaled down to match the individual’s voluntary range of motion through a nonlinear workspace mapping. Assistance is provided within that workspace only. Experimental results in 5 different experimental scenarios with a person with cerebral palsy confirm the suitability of the proposed framework.

  9. B. DeBoon, R. Foley, N. La Delfa, S. Nokleby, and C. Rossa - Nine Degree-of-Freedom Kinematic Modelling of the Upper Limb Complex for Constrained Workspace Evaluation. ASME Journal of Biomechanics, 2021, 143(2): 021009. 10.1115/1.4048573 (pdf) BibTeX

    @Article{DeBoon2020,
    author={B. DeBoon, and R. Foley, and N. La Delfa, and S. Nokleby, and C. Rossa},
    journal={ASME Journal of Biomechanics},
    title={Nine Degree-of-Freedom Kinematic Modelling of the Upper Limb Complex for Constrained Workspace Evaluation},
    year={2021},
    volume={143},
    number={2},
    pages={021009},
    doi={10.1115/1.4048573},
    publisher={American Society of Mechanical Engineers Digital Collection}
    ISSN={},
    }

    Abstract

    The design of rehabilitation devices for patients experiencing musculoskeletal disorders (MSDs) requires a great deal of attention. This paper aims to develop a comprehensive model of the upper limb complex to guide the design of robotic rehabilitation devices that prioritize patient safety, while targeting effective rehabilitative treatment. A 9 degreeof- freedom kinematic model of the upper limb complex is derived to assess the workspace of a constrained arm as an evaluation method of such devices. Through a novel differential inverse kinematic method accounting for constraints on all joints, the model determines the workspaces in which a patient is able to perform rehabilitative tasks and those regions where the patient needs assistance due to joint range limitations resulting from an MSD. Constraints are imposed on each joint by mapping the joint angles to saturation functions, whose joint-space derivative near the physical limitation angles approaches zero. The model Jacobian is reevaluated based on the nonlinearly mapped joint angles, providing a means of compensating for redundancy while guaranteeing feasible inverse kinematic solutions.
    The method is validated in three scenarios with different constraints on the elbow and palm orientations. By measuring the lengths of arm segments and the range of motion for each joint, the total workspace of a patient experiencing an upper-limb MSD can be compared to a pre-injured state. This method determines the locations in which a rehabilitation device must provide assistance to facilitate movement within reachable space that is limited by any joint restrictions resulting from MSDs.

  10. Arnaud Lelevé, Troy McDaniel, and C. Rossa - Haptic training simulation: Current state and open challenges. Frontiers in Virtual Reality, section Technologies for VR, 2020. Perspective paper. 10.3389/frvir.2020.00003 (pdf) BibTeX

    @Article{Levele2020,
    author={A. Lelevé, and T. McDaniel, and C. Rossa},
    journal={Frontiers in Virtual Reality},
    title={Haptic training simulation: Current state and open challenges},
    year={2020},
    volume={},
    pages={},
    doi={10.3389/frvir.2020.00003},
    ISSN={},
    }

    Abstract

    Immersive virtual environments combined with haptic (kinaesthetic and/or tactile) feedback are becoming an essential building block of simulator training in a variety of applications. This paper aims to illustrate the interest of hands-on training simulation with haptic feedback. We review the recent application domains and we expose the progress and open challenges in the medical domain which is particularly demonstrative. The paper then addresses two aspects of haptic feedback that could help enhance modern haptic training simulators' performance, namely transparent and efficient actuation for kinaesthetic feedback and tactile feedback. This research topic, beyond technological progress, should help design kinaesthetic and tactile haptic interfaces and motivate the use of new actuation techniques for more realistic and effective feedback in simulations as soon as users are immersed in virtual environments.

  11. M. Lacki, and C. Rossa - Design and control of a 3-degree-of-freedom parallel passive haptic device. IEEE Transactions on Haptics, 2020, in press. 10.1109/TOH.2020.2983037 (pdf) BibTeX

    @Article{Lacki2020a,
    author={M. Lacki and C. Rossa},
    journal={IEEE Transactions on Haptics},
    title={Design and control of a 3-degree-of-freedom parallel passive haptic device},
    year={2020},
    volume={},
    pages={},
    doi={10.1109/TOH.2020.2983037},
    ISSN={1939-1412},
    }

    Abstract

    Abstract—Robotic surgery and surgical simulation provide surgeons with tools that can improve the health outcomes of their patients. The limiting factor in many of these systems, however, is the haptic system which needs to render high impedance without compromising transparency or stability. To address this issue, we constructed a 3-Degree-of-Freedom haptic device using brakes as actuators. To control this device, we developed a novel controller, which increases the range of forces the device can generate and eliminates stiction. The parallel kinematic structure (known as delta) of the device makes it light and rigid. Since brakes are intrinsically stable, the device safely generates a wide range of impedance, making it well suited for many surgical applications.
    The novel controller attempts to minimize the sum of forces acting perpendicular to the virtual surface eliminating un-smooth force output and stiction, characteristic to passive devices, while increasing the range of displayable forces. The controller was validated using six testing scenarios, where it rendered contact with frictionless surfaces. When using the controller, the device rendered the desired surface without sticking. Since the controller successfully rendered this extreme geometry, it can also work in other applications, like robotic surgery and surgical simulation.

  12. M. Lacki, B. DeBoon, and C. Rossa - Impact of kinematic structure on the force displayability of planar passive haptic devices. IEEE Transactions on Haptics, vol. 13, no. 1, pp. 219-225, 2020. Also selected for presentation at the 2020 Haptics Symposium. 10.1109/TOH.2020.2970906 (pdf) BibTeX

    @Article{Lacki2020,
    author={M. Lacki and B. DeBoon and C. Rossa},
    journal={IEEE Transactions on Haptics},
    title={Impact of kinematic structure on the force displayability of planar passive haptic devices},
    year={2020},
    volume={13},
    pages={219-225},
    doi={10.1109/TOH.2020.2970906},
    ISSN={1939-1412},
    }

    Abstract

    Haptic devices containing passive actuators, such as controllable brakes or dampers, are an attractive alternative to their motor-driven counterparts due to intrinsic stability and improved impedance bandwidth. Passive actuators cannot generate energy, and, therefore, the output force can only oppose the applied velocity. In the same way the kinematic structure of traditional manipulators is designed to maximize dexterity and manipulability, one must consider adapting the device topology to optimize force displayability when designing passive actuators.
    This paper introduces a set of metrics to evaluate and compare the performance of 2-degree-of-freedom serial and parallel passive haptic devices. These metrics consider the impact of the kinematic structure on the force displayability of 9 unique configurations. It is shown that: 1.) Serial manipulators can generate passive forces in all directions equally regardless of the link length ratio; 2.) The base link length of 5-bar parallel manipulators strongly influences passive force displayability; and 3.) 5-bar parallel manipulators with the base link length of zero can generate the widest range of passive forces when all links have the same length. The novel performance metrics presented in this paper can aid in the design of 2-DOF passive haptic devices.

  13. B. Sainsbury, M. Lacki, M. Shahait, M. Goldenberg, A. Baghdadi, L. Cavuoto, J. Ren, M. Green, J. Lee, T. D'Averch, and C. Rossa - Evaluation of a Virtual Reality Percutaneous Nephrolithotomy (PCNL) Surgical Simulator. Frontiers in Robotics and AI, Virtual Environments, AI 6:145, 2020. 10.3389/frobt.2019.00145 (pdf) BibTeX

    @Article{Sainsbury2019,
    author={B. Sainsbury and M. Lacki and M. Shahait and M. Goldenberg and A. Baghdadi and L. Cavuoto and J. Ren and M. Green and J. Lee and T. D'Averch and and C. Rossa},
    journal={Frontiers in Robotics and AI},
    title={Evaluation of a Virtual Reality Percutaneous Nephrolithotomy (PCNL) Surgical Simulator},
    year={2020},
    volume={6:145},
    pages={},
    doi={10.3389/frobt.2019.00145},
    ISSN={2296-9144},
    }

    Abstract

    Percutaneous Nephrolithotomy is the standard surgical procedure used to remove large kidney stones. PCNL procedures have a steep learning curve; a physician needs to complete between 36-60 procedures, to achieve clinical proficiency. Marion Surgical K181 is a virtual reality surgical simulator, which emulates the PCNL procedures without compromising the well-being of patients. The simulator uses a VR headset to place a user in a realistic and immersive operating theatre, and haptic force-feedback robots to render physical interactions between surgical tools and the virtual patient. The simulator has two modules for two different aspects of PCNL kidney stone removal procedure: kidney access module where the user must insert a needle into the kidney of the patient, and a kidney stone removal module where the user removes the individual stones from the organ.
    In this paper, we present user trials to validate the face and construct validity of the simulator. The results, based on the data gathered from 4 groups of users independently, indicate that Marion’s surgical simulator is a useful tool for teaching and practicing PCNL procedures. The kidney stone removal module of the simulator has proven construct validity by identifying the skill level of different users based on their tool path. We plan to continue evaluating the simulator with a larger sample of users to reinforce our findings.

  14. M. Najafi, C. Rossa, K. Adams, and M. Tavakoli - Using potential field function with a velocity field controller to learn and reproduce the therapist's assistance in robotic-assisted rehabilitation. IEEE Transactions on Mechatronics, 2020, in press, 10.1109/TMECH.2020.2981625 BibTeX

    @Article{Najafi2020,
    author={M. Najafi and C. Rossa and K. Adams and M. Tavakoli},
    journal={Transactions on Mechatronics},
    title={Using potential field function with a velocity field controller to learn and reproduce the therapist's assistance in robotic-assisted rehabilitation},
    year={2020},
    volume={},
    pages={},
    doi={10.1109/TMECH.2020.2981625},
    ISSN={1083-4435},
    }

    Abstract

    Rehabilitative and assistive practices usually elicit intense and repetitive exercises. Thus, there has been an increasing interest in robotic systems as they are robust and costeffective in comparison to conventional physical motor-therapy with a therapist. These robots have applications in therapeutic and in-home environments, where there is a necessity for a userfriendly procedure to program the robots for a specific task easily. Our group has suggested robot learning from demonstration (LfD) as an intuitive procedure to program robots via short-term physical interaction in rehabilitation and assistive applications. In this paper, a therapist assists a patient, and cooperatively performs a task on a robotic manipulator. Then, using a non-parametric potential field function, the therapist’s motion and interaction force (assistance/resistance) is modelled time-independently via a convex optimization algorithm. Next, in the therapist’s absence, the robot provides the patient with the same level of interaction force provided by the therapist along the trajectory. A velocity field controller is also designed to compensate and regulate the patient’s deviation from the velocity observed in the demonstration phase. Finally, the efficacy, advantages, and stability of the proposed framework are evaluated in three different experimental scenarios involving spring arrays and an individual with Cerebral Palsy.

  15. B. Fallahi, M. Waine, C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - An integrator-backstepping control approach for 3D needle steering. IEEE Transactions on Mechatronics, vol. 24, no. 5, pp. 2204-2014, 2019. 10.1109/TMECH.2019.2930732
    BibTeX

    @Article{Fallahi2019,
    author={B. Fallahi and M. Waine and C. Rossa and R. Sloboda and N. Usmani and M. Tavakoli},
    journal={Transactions on Mechatronics},
    title={An Integrator-Backstepping Control Approach for 3D Needle Steering},
    year={2019},
    volume={24},
    pages={2204-2214},
    doi={10.1109/TMECH.2019.2930732},
    ISSN={1083-4435},
    }

    Abstract

    In this paper, we design a set of 2D needle steering controllers used to minimize the 3D deflection of a flexible, bevel- tipped needle. The controllers are based on a nonlinear design tool known as integrator-backstepping. The needle’s deflection is split into its two 2D planar problems, each of which is then governed by its own, separate controller. One controller, called Vertical Deflection Control (VDC), steers the needle so that it deflects primarily along the vertical plane. The second controller, called Horizontal Deflection Control (HDC), steers the needle so that it deflects primarily along the horizontal plane. Our 3D steering algorithm combines the effect of these two controllers based on the current magnitude of the deflection along each plane. Using an 18 gauge brachytherapy needle, we tested our proposed method on a phantom tissue composed of liquid plastic, and a two-layer biological tissue formed of gelatin and ex-vivo beef. Without needle steering, the average needle deflection was 11.2 mm. Using the proposed 3D needle steering technique, the deflection decreased to an average of 0.5 mm.

  16. M. Khadem, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - Geometric control of 3D needle steering in soft-tissue. Automatica, vol. 101, pp. 36-43, 2018. 10.1016/j.automatica.2018.11.018 (pdf) BibTeX

    @Article{Khadem2018,
    author={M. Khadem and C. Rossa and N. Usmani and R. Sloboda and M. Tavakoli},
    journal={Automatica},
    title={Geometric Control of 3D Needle Steering in Soft-Tissue},
    year={2018},
    volume={101},
    pages={36-43},
    doi={10.1016/j.automatica.2018.11.018},
    ISSN={0005-1098},
    }

    Abstract

    In this paper, a 3D automated needle steering system is presented that can enhance the performance of needle-based procedures. The system comprises a nonholonomic needle steering model and a nonlinear controller for 3D needle steering. First, a reduced-order needle steering model is presented. Next, a geometric reduction procedure is carried out to present the nonlinear control system in a transformed format. Finally, the transformed model is used to design a two-step controller. The controller rst stabilizes the system on an equilibrium manifold of the system and later employs a switching law to stabilize it on an equilibrium point in the manifold. The former performs insertion of the needle up to a desired depth and the latter performs retraction/insertion motion that guides the needle toward a desired point at the given depth. Validation experiments are performed on a phantom and ex-vivo animal tissues and the results are compared with manual needle insertions performed by skilled surgeons. The mean error of our 3D needle steering system is 60% less than manual needle insertions.

  17. J. Carriere, M. Khadem, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - Event-triggered 3D needle control using a reduced-order computationally efficient bicycle model in a constrained optimization framework. In Journal of Medical Robotics Research, vol 4, no.1, 190200, 2018. 10.1142/S2424905X18420047 ( pdf) BibTeX

    @Article{Carriere2018,
    author={J. Carrierre and M. Khadem and C. Rossa and N. Usmani and R. Sloboda and M. Tavakoli},
    journal={Journal of Medical Robotics Research},
    title={Event-triggered 3D needle control using a reduced-order computationally efficient bicycle model in a constrained optimization framework},
    year={2018},
    volume={4},
    number={1},
    pages={190200},
    doi={10.1142/S2424905X18420047},
    ISSN={2424-9068},
    }

    Abstract

    Long flexible needles used in percutaneous procedures such as biopsy and brachytherapy deflect during insertion, thus reducing needle-tip placement accuracy. This paper presents a surgeon-in-the-loop system to automatically steer the needle during manual insertion and compensate for needle deflection using an event-triggered controller. A reduced-order kinematic bicycle model incorporating needle-tip measurement data from ultrasound images is used to determine steering actions required to minimize needle deflection.

    To this end, an analytic solution to the reduced-order bicycle model, which is shown to be more computationally eficient than a discrete-step implementation of the same model, is derived and utilized for needle-tip trajectory prediction. These needle-tip trajectory predictions are used online to optimize the insertion depths (event-trigger points) for steering actions such that needle deflection is minimized. The use of the analytic model and the event-triggered controller also allows for limiting the number and extent of needle rotations (to reduce tissue trauma) in a constrained optimization framework. The system was tested experimentally in three di fferent ex-vivo tissue phantoms with a surgeon-in-the-loop needle insertion device. The proposed needle steering controller was shown to keep the average needle deflection within 0.47 mm at the fi nal insertion depth of 120 mm.

  18. M. Khadem, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - Robotic-assisted needle steering around anatomical obstacles using notched steerable needles. IEEE Journal of Biomedical and Health Informatics, vol. 22, no. 5, pp. 1917-1928, 2018. 10.1109/JBHI.2017.2780192 ( pdf) BibTeX

    @Article{Khadem2017c,
    author={M. Khadem and C. Rossa and N. Usmani and R. Sloboda and M. Tavakoli},
    journal={IEEE Journal of Biomedical and Health Informatics},
    title={Robotic-assisted needle steering around anatomical obstacles using notched steerable needles},
    year={2017},
    volume={},
    pages={},
    doi={10.1109/JBHI.2017.2780192},
    ISSN={2168-2194},
    month={},}

    Abstract

    Robotic-assisted needle steering can enhance the accuracy of needle-based interventions. Application of current needle steering techniques are restricted by the limited deflection curvature of needles. Here, a novel steerable needle with improved curvature is developed and used with an online motion planner to steer the needle along curved paths inside tissue. The needle is developed by carving series of small notches on the shaft of a standard needle. The notches decrease the needle flexural stiffness, allowing the needle to follow tightly curved paths with small radius of curvature (ROC).

    In this paper, first a finite element model of the notched needle deflection in tissue is presented. Next, the model is used to estimate the optimal location for the notches on needle’s shaft for achieving a desired curvature. Finally, an ultrasound-guided motion planner for needle steering inside tissue is developed and used to demonstrate the capability of the notched needle in achieving high curvature and maneuvering around obstacles in tissue. We simulated a clinical scenario in brachytherapy, where the target is obstructed by the pubic bone and cannot be reached using regular needles. Experimental results show that the target can be reached using the notched needle with a mean accuracy of 1.2 mm. Thus, the proposed needle enables future research on needle steering toward deeper or more difficult-to-reach targets.

  19. J. Carriere, M. Khadem, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - Surgeon-in-the-loop 3D needle steering through ultrasound-guided feedback control. IEEE Robotic and Automation Letters , vol. 3, no. 1, pp. 469-476 2018. 10.1109/LRA.2017.2768122 ( pdf) BibTeX

    @Article{Carriere2017,
    author={J. Carrierre and M. Khadem and C. Rossa and N. Usmani and R. Sloboda and M. Tavakoli},
    journal={IEEE Robotics and Automation Letters},
    title={Surgeon-in-the-loop 3D needle steering through ultrasound-guided feedback control.},
    year={2018},
    volume={3},
    number={1},
    pages={469-476},
    doi={},
    ISSN={2377-3766},
    doi={10.1109/LRA.2017.2768122},}

    Abstract

    Needle deflection during certain minimally invasive percutaneous procedures, such as prostate biopsy or brachytherapy, is undesired and can be reduced through the use of feedback control. This paper uses a depth-dependent reduced-order 3D nonholonomic model of needle tip motion to propose a needle deflection controller that works in a surgeon-in-the-loop fashion, where the surgeon is in charge of needle insertion, and the feedback controller is responsible for keeping the needle on its desired trajectory.

    The controller is based on a continuous-time control law that asymptotically brings needle deflection to zero, and is shown to remain effective even when the magnitude of the needle rotation velocity is limited. Limiting of the needle rotational velocity is due to practical considerations such as to reduce tissue damage during insertion and to show a measure of velocity-independence of the controller when high insertion speeds would require unfeasibly fast rotations. The velocitylimited controller is evaluated in three different ex-vivo tissue samples in a total of 30 needle insertion trials using real-time needle deflection measurements from ultrasound images. The exvivo results show an average absolute needle tip deflection of 0.54 mm away from the target location at a depth of 120 mm, and an average needle tip deflection of 0.36 mm away from the desired target axis throughout the entire insertion length.

  20. T. Lehmann, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - Deflection modeling for a needle actuated by lateral force and axial rotation during insertion in soft phantom tissue. In IFAC Mechatronics Journal (Elsevier), vol. 48, pp. 52-53, 2017. 10.1016/j.mechatronics.2017.10.008 ( pdf) BibTeX

    @Article{Lehmann2017b,
    author={T. Lehmann and C. Rossa and N. Usmani and R. Sloboda and M. Tavakoli},
    journal={Mechatronics},
    title={Deflection modeling for a needle actuated by lateral force and axial rotation during insertion in soft phantom tissue.},
    year={2017},
    volume={48},
    pages={42-53},
    doi={10.1016/j.mechatronics.2017.10.008},
    ISSN={0957-4158},
    month={},}

    Abstract

    In prostate brachytherapy, radioactive seeds are implanted into the prostate for treatment of early-stage localized cancer. A major issue is seed displacement due to needle deflection, which is difficult to control as the needle is inserted manually. To address the problem and automate needle insertion, robotic systems, mathematical models for estimation and prediction and control algorithms have been developed.The method of choice for robotic steering of beveled-tip needles is predominantly intermittent axial needle rotation since this re-aligns the beveled tip and thus re-directs the needle.

    In this work, we present a method for needle steering to supplement axial needle rotation. A point force applied laterally to the needle near its point of insertion into tissue is used to displace the needle perpendicularly relative to its insertion axis. An advantage of this method is that the lateral force provides a continuous control input and thus continuous deflection control as opposed to axial needle rotation by 180 degrees in the 2D case of planar needle steering. Further, more control over deflection is possible as the lateral force provides direct shape change for the needle and improves the under-actuated nature of the needle. In order to predict and estimate needle deflection during insertion while applying both lateral force and axial rotation, a mechanics- and energy-based model for needle deflection is developed. The accuracy of the model is validated experimentally. A comparison between the measured tip deflection and the model-based estimate shows only a small error. Moreover, control and sensitivity studies are carried out through insertion simulations using the model. The studies show the potentials and limitations for needle deflection reduction with various combinations of lateral force application and intermittent 180 degrees axial needle rotation.

  21. T. Lehmann, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - Intraoperative tissue Youngs modulus identification during needle insertion using a laterally actuated needle. In IEEE Transactions on Instrumentation & Measurement, vol. 67, no. 2, pp. 371-381, 2017. 10.1109/TIM.2017.2774182 (pdf) BibTeX

    @Article{Lehmann2017,
    author={T. Lehmann and C. Rossa and N. Usmani and R. Sloboda and M. Tavakoli},
    journal={IEEE Transactions on Instrumentation & Measurement},
    title={Intraoperative tissue Youngs modulus identification during needle insertion using a laterally actuated needle},
    year={2017},
    volume={67},
    number={2},
    pages={371-381},
    doi={10.1109/TIM.2017.2774182},
    ISSN={0018-9456},
    month={Feb},}

    Abstract

    Needle insertion is a common minimally invasive medical procedure used for therapy and diagnosis. Among the therapeutic procedures is prostate brachytherapy, during which needle insertion is applied to implant radioactive seeds within the prostate. During insertion, the needle tends to deflect from a desired straight path thus causing misplacement of the seeds. While currently the needle is steered manually to correct for needle deflection, robotic assistance can be used towards this goal.

    A requirement for accurate robotic needle steering is needle deflection estimation or prediction obtained from needle deflection modeling. Various mechanics-based deflection models based on needle-tissue interactions have been introduced in the literature. Many models require the tissue Young's modulus as parameter input that can be measured or quantified using methods of varying limitations with regard to complexity or access in the operating room. This work proposes an intraoperative method for the identification of tissue Young's modulus using lateral actuation of the needle. The needle-tissue system's response in terms of needle deflection and thus tissue displacement is observed during lateral needle displacement. The tissue Young's modulus is then identified based on the energy stored in the needle-tissue system. Using this method, the actuated needle itself is the tool used to obtain the tissue Young's modulus, facilitating clinical implementation. Experimental studies are presented to confirm a high accuracy of the identified tissue Young's modulus when compared to an independent measurement. Moreover, the prediction accuracy of a deflection model that is calibrated with the proposed method is verified experimentally.

  22. B. Fallahi, C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - Sliding-based image-guided 3D needle steering in soft tissue. In Control Engineering Practice, vol. 63, pp. 34-43, 2017. 10.1016/j.conengprac.2017.04.001 ( pdf) BibTeX

    @Article{Fallahi2017,
    author={B. Fallahi and C. Rossa and R. S. Sloboda and N. Usmani and M. Tavakoli},
    journal={Control Engineering Practice},
    title={Sliding-based image-gided 3D needle steering in soft tissue},
    year={2017},
    volume={63},
    pages={34-43},
    doi={10.1016/j.conengprac.2017.04.001},
    ISSN={0967-0661},
    month={June},}

    Abstract

    This paper presents a sliding-based method for steering beveled-tip needles in a 3D environment. The controller determines the needle roll angle using the needle tip position deviation, obtained from ultrasound images, and its fi rst time derivative. The stability of the closed-loop system is analyzed using 3D unicycle model for the needle, as a result of which parameter constraints are derived. In this method the needle is steered by performing adjustments of needle orientation, which reduces the tissue trauma and injury. The performance of this method is verifi ed by performing experiments using phantom tissue for environments with and without obstacles.

  23. C. Rossa, and M. Tavakoli - Issues in closed-loop needle steering. In Control Engineering Practice, vol. 62, pp. 55-69, 2017. 10.1016/j.conengprac.2017.03.004 ( pdf) BibTeX

    @Article{Rossa2017,
    Title = {Issues in closed-loop needle steering },
    Author = {Carlos Rossa and Mahdi Tavakoli},
    Journal = {Control Engineering Practice },
    Year = {2017},
    Pages = {55-69},
    Volume = {62},
    Doi = {10.1016/j.conengprac.2017.03.004},
    ISSN = {0967-0661},
    Keywords = {Feedback control},
    Url = {http://www.sciencedirect.com/science/article/pii/S0967066117300606}
    }

    Abstract

    Percutaneous needle insertion is amongst the most prevalent clinical procedures. The effectiveness of needlebase interventions heavily relies on needle targeting accuracy. However, the needle interacts with the surrounding tissue during insertion and deflects away from its intended trajectory. To overcome this problem, a significant research effort has been made towards developing robotic systems to automatically steer beveltipped needles percutaneously, which is a comprehensive and challenging control problem. A flexible needle inserted in soft tissue is an under-actuated system with nonholonomic constraints. Closed-loop feedback control of needle in tissue is challenging due to measurement errors, unmodelled dynamics created by tissue heterogeneity, and motion of targets within the tissue. In this paper, we review recent progress made in each of the complementary components that constitute a closed-loop needle steering system, including modelling needle-tissue interaction, sensing needle deflection, controlling needle trajectory, and hardware implementation.

  24. C. Rossa, T. Lehmann, R. Sloboda, N. Usmani, and M. Tavakoli - A data-driven soft sensor for needle deflection in heterogeneous tissue using just-in-time modelling. In Medical & Biological Engineering & Computing, vol 55, no 8, pp. 1401-1414, 2017. 10.1007/s11517-016-1599-1 ( pdf) BibTeX

    @Article{Rossa2016data,
    author={Rossa, Carlos and Lehamnn, Thomas and Sloboda, Ron and Usmani, Nawaid and Tavakoli, Mahdi},
    title={A Data-Driven Soft Sensor for Needle Deflection in Heterogeneous Tissue using Just-in-Time Modelling},
    journal={Medical & Biological Engineering & Computing},
    year={2017},
    pages={1401-1414},
    volume={55},
    number={8},
    issn={0140-0118},
    doi={10.1007/s11517-016-1599-1},
    url={http://dx.doi.org/10.1007/s11517-016-1599-1} }

    Abstract

    Global modelling has traditionally been the approach taken to estimate needle deflection in soft tissue. In this paper, we propose a new method based on local data-driven modelling of needle deflection. External measurements of needle-tissue interactions are collected from several insertions in ex-vivo tissue to form a cloud of data. Inputs to the system are the needle insertion depth, axial rotations, and the forces and torques measured at the needle base by a force sensor. When a new insertion is performed, the Just-in-Time (JIT) learning method estimates the model outputs given the current inputs to the needle-tissue system and the historical database. The query is compared to every observation in the database and is given weights according to some similarity criteria. Only a subset of historical data that is most relevant to the query is selected and a local linear model is fit to the selected points to estimate the query output. The model outputs the 3D deflection of the needle tip and the needle insertion force. The proposed approach is validated in ex-vivo multi-layered biological tissue in different needle insertion scenarios. Experimental results in 5 different case studies indicate an accuracy in predicting needle deflection of 0.81 mm and 1.24 mm in the horizontal and vertical planes, respectively, and an accuracy of 0.5 N in predicting the needle insertion force over 216 needle insertions.

  25. M. Khadem, C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - Semi-automated needle steering in biological tissue using an ultrasound-based deflection predictor. In Annals of Biomedical Engineering, vol. 54, no. 4, pp. 924-938, 2016. 10.1007/s10439-016-1736-x ( pdf) BibTeX

    @Article{Khadem2017a,
    author={Khadem, Mohsen and Rossa, Carlos and Usmani, Nawaid and Sloboda, Ron and Tavakoli, Mahdi},
    title={Semi-Automated Needle Steering in Biological Tissue Using an Ultrasound-Based Deflection Predictor},
    journal={Annals of Biomedical Engineering},
    year={2017},
    pages={924-938},
    volume={45},
    number={4},
    issn={1573-9686},
    doi={10.1007/s10439-016-1736-x},
    url={http://dx.doi.org/10.1007/s10439-016-1736-x} }

    Abstract

    The performance of needle-based interventions depends on the accuracy of needle tip positioning. Here, a novel needle steering strategy is proposed that enhances accuracy of needle steering. In our approach the surgeon is in charge of needle insertion to ensure the safety of operation, while the needle tip bevel location is robotically controlled to minimize the targeting error. The system has two main components: (1) a real-time predictor for estimating future needle deflection as it is steered inside soft tissue, and (2) an online motion planner that calculates control decisions and steers the needle toward the target by iterative optimization of the needle deflection predictions. The predictor uses the ultrasound-based curvature information to estimate the needle deflection. Given the specification of anatomical obstacles and a target from preoperative images, the motion planner uses the deflection predictions to estimate control actions, i.e., the depth(s) at which the needle should be rotated to reach the target. Ex-vivo needle insertions are performed with and without obstacle to validate our approach. The results demonstrate the needle steering strategy guides the needle to the targets with a maximum error of 1.22 mm.

  26. T. Lehmann, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - A real-time estimator for needle deflection during insertion into soft tissue based on adaptive modelling of needle tissue interactions. In IEEE Transactions on Mechatronics, vol 21, no. 6, pp. 2601-2612, 2016. 10.1109/TMECH.2016.2598701 ( pdf) BibTeX

    @Article{Lehmann2016a,
    author={T. Lehmann and C. Rossa and N. Usmani and R. S. Sloboda and M. Tavakoli},
    journal={IEEE/ASME Transactions on Mechatronics},
    title={A Real-Time Estimator for Needle Deflection During Insertion Into Soft Tissue Based on Adaptive Modeling of Needle-Tissue Interactions},
    year={2016},
    volume={21},
    number={6},
    pages={2601-2612},
    doi={10.1109/TMECH.2016.2598701},
    ISSN={1083-4435},
    month={Dec}, }

    Abstract

    This work proposes a real-time estimator for needle tip deflection and needle shape during needle insertion into soft tissue. The estimator is based on an adaptive quasi-static mechanics-based model for needle–tissue interactions. The model uses Euler–Bernoulli beam theory to model the needle as a cantilever beam that experiences loads imposed by the tissue. The modeled needle–tissue interactions consist of a distributed load along the inserted needle portion and tissue cutting-related point load at the needle tip. We propose a closed-form solution to quantify the magnitude of these needle–tissue interaction loads based on force and torque measured at the needle base. The model adaptively adjusts the shape of the distributed load as the needle is inserted. Experiments are carried out into gelatin phantom and porcine tissue to validate the deflection estimate's performance. The newly proposed model's performance is compared against a previously proposed quasi-static model for needle-deflection estimation. It is shown that the novel model outperforms the previously proposed model.

  27. C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - A hand-held assistant for semi-automated percutaneous needle steering. In IEEE Transactions on Biomedical Engineering, vol 64, no. 3, pp. 637-648, 2016. 10.1109/TBME.2016.2565690 ( pdf)
    BibTeX

    @Article{Rossa2016a,
    author={C. Rossa and N. Usmani and R. Sloboda and M. Tavakoli},
    journal={IEEE Transactions on Biomedical Engineering},
    title={A Hand-Held Assistant for Semi-Automated Percutaneous Needle Steering},
    year={2017},
    volume={64},
    number={3},
    pages={637-648},
    doi={10.1109/TBME.2016.2565690},
    ISSN={0018-9294},
    month={March},
    }

    Video

    Abstract

    Objective: Permanent prostate brachytherapy is an effective and popular treatment modality for prostate cancer in which long needles are inserted into the prostate. Challenges associated with manual needle insertion such as needle deflection limit this procedure to primarily treat the entire prostate gland even for patients with localized cancer. In this paper we present a new semi-automated hand-held needle steering assistant designed to help surgeons improve needle placement accuracy.
    Methods: Regular clinical brachytherapy needles are connected to a compact device that the surgeon holds. As the surgeon inserts the needle, the device rotates the needle base on a measured and calculated basis in order to produce a desired trajectory of the needle tip. A novel needle-tissue interaction model and a steering algorithm calculate such control actions based on ultrasound images of the needle in tissue. The assistant can also apply controlled longitudinal microvibrations to the needle that reduce needle-tissue friction.
    Results: Experimental validation of the proposed system in phantom and ex-vivo biological tissue report an average needle targeting accuracy of 0.33 mm over 72 needle insertions in 12 different experimental scenarios. Conclusion: We introduce a new framework for needle steering in prostate brachytherapy in which the surgeon remains in charge of the needle insertion. The device weighs 160 grams, making it easy to incorporate with current insertion techniques.
    Significance: Expected benefits of the proposed system include more precise needle targeting accuracy, which can result in improved focal treatment of prostate cancer.

  28. M. Khadem , C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - A two-body rigid/flexible model of needle steering dynamics in soft tissue. In IEEE/ASME Transactions on Mechatronics, vol 11, no. 5, pp. 2352-2364, 2016. 10.1109/TMECH.2016.2549505 ( pdf) BibTeX

    @Article{Khadem2016b,
    author={M. Khadem and C. Rossa and N. Usmani and R. S. Sloboda and M. Tavakoli},
    journal={IEEE/ASME Transactions on Mechatronics},
    title={A Two-Body Rigid/Flexible Model of Needle Steering Dynamics in Soft Tissue},
    year={2016},
    volume={21},
    number={5},
    pages={2352-2364},
    doi={10.1109/TMECH.2016.2549505},
    ISSN={1083-4435},
    month={Oct},}

    Abstract

    Robotics-assisted needle steering can enhance targeting accuracy in percutaneous interventions. This paper presents a novel dynamical model for robotically controlled needle steering. This is the first model that predicts both needle shape and tip position in soft tissue, and accepts needle insertion velocity, needle 180° axial rotation, and needle base force/torque as inputs. A hybrid formulation of needle steering dynamics in soft tissue is presented, which considers the needle as a two-body rigid/flexible coupled system composed of a moving, discrete, and rigid part attached to a vibrating compliant part that is subject to external excitation forces. The former is the carrier representing the surgeon's hand or the needle inserting robot, while the latter is a beam modeling the continuous deflection of the needle inside tissue. A novel time-delayed tissue model and a fracture mechanics-based model are developed to model the tissue reaction forces and cutting force at the needle tip, respectively. Experiments are performed on synthetic and ex vivo animal tissues to identify the model parameters and validate the needle steering model. The maximum error of the 2-D model in predicting the needle tip position in the insertion plane was 1.59 mm in the case of no axial rotation and 0.74 mm with axial rotation.

  29. B. Fallahi, C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - Sliding-based switching control for image-guided needle steering in soft tissue. In IEEE Robotics and Automation Letters (RA-L), vol 1, no. 2, pp860-867, 2016. 10.1109/LRA.2016.2528293 ( pdf) BibTeX

    @Article{Fallahi2016a,
    author={B. Fallahi and C. Rossa and R. S. Sloboda and N. Usmani and M. Tavakoli},
    journal={IEEE Robotics and Automation Letters},
    title={Sliding-Based Switching Control for Image-Guided Needle Steering in Soft Tissue},
    year={2016},
    volume={1},
    number={2},
    pages={860-867},
    doi={10.1109/LRA.2016.2528293},
    ISSN={2377-3766},
    month={July},}

    Abstract

    This letter represents a sliding-based controller for steering beveled-tip needles to stationary locations in soft tissue in a 2-D environment by performing appropriate switches of bevel orientation by 180° axial rotations while the needle is being inserted. Assuming the rotation velocity to be large enough with respect to insertion velocity, the out of plane motions of the needle can be neglected. The proposed controller has a nonmodel-based structure, which is fed by the needle tip deflection error and its derivative obtained from ultrasound images and outputs the switching pattern as the control law. To analyze the stability and convergence of the error, the kinematic unicycle model for beveled-tip needle motion in soft tissue is employed and the constraints on switching parameters are derived. The performance of the controller in the sense of targeting error and number of switches is verified using an experimental setup to insert the needle into gelatin phantom tissue and ex-vivo biological tissue.

  30. M. Khadem C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - Mechanics of tissue cutting during needle insertion in biological Tissue. In IEEE Robotics and Automation Letters (RA-L), vol 1, no. 2, pp 800-807, 2016. 10.1109/LRA.2016.2528301 ( pdf) BibTeX

    @Article{Khadem2016c,
    author={M. Khadem and C. Rossa and R. S. Sloboda and N. Usmani and M. Tavakoli},
    journal={IEEE Robotics and Automation Letters},
    title={Mechanics of Tissue Cutting During Needle Insertion in Biological Tissue},
    year={2016},
    volume={1},
    number={2},
    pages={800-807},
    doi={10.1109/LRA.2016.2528301},
    ISSN={2377-3766},
    month={July},}

    Abstract

    In percutaneous needle insertions, cutting forces at the needle tip deflect the needle and increases targeting error. Thus, modeling needle-tissue interaction in biological tissue is essential for accurate robotics-assisted needle steering. In this letter, dynamics of needle tip interaction with inhomogeneous biological tissue is described and the effects of insertion velocity, tissue mechanical characteristics, and needle geometry on tissue cutting force are studied. Needle interaction with biological tissue is divided into three distinct events and modeled. 1) Initial tissue puncturing, which starts by soft tissue deformation and continues until a crack is formed in the tissue. Employing a viscoelastic model of fracture initiation we have predicted the maximum puncturing force and force-displacement response of a needle in contact with a tissue. 2) Tissue cutting, which follows the crack propagation in tissue and is predicted using a novel energy-based fracture model. The model takes account of the needle tip geometry and the tissue mechanical characteristics. 3) Friction between tissue and needle shaft is estimated during needle insertion and retraction using a needle-tissue friction model. Using a needle driving robot ex vivo experiments are performed on a porcine tissue sample to identify the model parameters and validate the analytical predictions offered by the models.

  31. C. Rossa, M. Khadem, , R. Sloboda, N. Usmani, and M. Tavakoli - Adaptive quasi-static modelling of needle deflection during steering in soft tissue. In IEEE Robotics and Automation Letters (RA-L), vol 1, no. 2, pp 916-923, 2016. 10.1109/LRA.2016.2527065 ( pdf) BibTeX

    @Article{Rossa2016b,
    author={C. Rossa and M. Khadem and R. Sloboda and N. Usmani and M. Tavakoli},
    journal={IEEE Robotics and Automation Letters},
    title={Adaptive Quasi-Static Modelling of Needle Deflection During Steering in Soft Tissue},
    year={2016},
    volume={1},
    number={2},
    pages={916-923},
    doi={10.1109/LRA.2016.2527065},
    ISSN={2377-3766},
    month={July},}

    Abstract

    In this letter, we present a model for needle deflection estimation in soft tissue. The needle is modelled as a vibrating compliant cantilever beam that experiences forces applied by the tissue as it is inserted. Each of the assumed vibration modes are associated with a weighting coefficient whose magnitude is calculated using the minimum potential energy method. The model only requires as input the tissue stiffness and needle-tissue cutting force. Contributions of this letter include the estimation of needle-tissue contact forces as a function of the tissue displacement along the needle shaft, while allowing for multiple bends of the needle. The model is combined with partial ultrasound image feedback in order to adaptively calculate the needle-tissue cutting force as the needle is inserted. The image feedback is obtained by an ultrasound probe that follows the needle tip and stops at an appropriate position to avoid further tissue displacement. Images obtained during early stages of the insertion are used to predict the deflection of the needle further along the insertion process. Experimental results in biological and phantom tissue show an average error in predicting needle deflection of 0.36 mm.

  32. C. Rossa, J. Fong, N. Usmani, R. Sloboda, and M. Tavakoli - Multi-actuator haptic feedback on the wrist for needle steering guidance in brachytherapy. In IEEE Robotics and Automation Letters (RA-L), vol 1, no. 2, pp 852-859, 2016. Also, selected for presentation at the IEEE International Conference on Robotics and Automation, Stockholm, Sweden, 2016. 10.1109/LRA.2016.2528295 ( pdf) BibTeX

    @Article{Rossa2016c,
    author={C. Rossa and J. Fong and N. Usmani and R. Sloboda and M. Tavakoli},
    journal={IEEE Robotics and Automation Letters},
    title={Multiactuator Haptic Feedback on the Wrist for Needle Steering Guidance in Brachytherapy},
    year={2016},
    volume={1},
    number={2},
    pages={852-859},
    doi={10.1109/LRA.2016.2528295},
    ISSN={2377-3766},
    month={July},}

    Video

    Abstract

    Brachytherapy is a cancer treatment procedure where long needles are inserted toward an inner body target in order to deliver radioactive seeds that treat the cancer cells. Controlling the trajectory of the needle is very challenging as it deviates from a straight path during insertion. In this letter, we present the pilot study of usefulness of a wristband with haptic feedback designed to help surgeons guide the needle toward a desired destination. The wristband embeds eight miniature actuators distributed around the wrist. The actuators are controlled to generate different haptic stimuli, each of which informs the user about a necessary needle steering manoeuvre. We describe the design of the wristband and its evaluation in two distinct user studies. In the first study, we evaluate how accurately users can identify the vibration patterns. In the second study, we focus on how the user responds to these patterns while performing needle insertion into tissue in an environment with high cognitive visual load. The reported average success rate in identifying the haptic pattern and the success rate in performing the correct action during needle insertion are 86% and 72%, respectively. These results suggest that the device could work in tandem with a needle steering algorithm to help surgeons achieve high quality implants and develop needle steering skills.

  33. M. Khadem, C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - Ultrasound-guided model predictive control of needle steering in biological tissue. In the Journal of Medical Robotics Research (JMRR), vol 1, no. 1, 2016. 10.1142/S2424905X16400079 ( pdf) BibTeX

    @Article{Khadem2016d,
    author = {Khadem, Mohsen and Rossa, Carlos and Sloboda, Ron S. and Usmani, Nawaid and Tavakoli, Mahdi},
    title = {Ultrasound-Guided Model Predictive Control of Needle Steering in Biological Tissue},
    journal = {Journal of Medical Robotics Research},
    volume = {01},
    number = {01},
    pages = {1640007},
    year = {2016},
    doi = {10.1142/S2424905X16400079},
    URL = {http://www.worldscientific.com/doi/abs/10.1142/S2424905X16400079},
    eprint = {http://www.worldscientific.com/doi/pdf/10.1142/S2424905X16400079} }

    Abstract

    In needle-based medical procedures, beveled tip flexible needles are steered inside soft tissue to reach the desired target locations. In this paper, we have developed an autonomous image-guided needle steering system that enhances targeting accuracy in needle insertion while minimizing tissue trauma. The system has three main components. First is a novel mechanics-based needle steering model that predicts needle deflection and accepts needle tip rotation as an input for needle steering. The second is a needle tip tracking system that determines needle deflection from the ultrasound images. The needle steering model employs the estimated needle deflection at the present time to predict needle tip trajectory in the future steps. The third component is a nonlinear model predictive controller (NMPC) that steers the needle inside the tissue by rotating the needle beveled tip. The MPC controller calculates control decisions based on iterative optimization of the predictions of the needle steering model. To validate the proposed ultrasound-guided needle steering system, needle insertion experiments in biological tissue phantoms are performed in two cases–with and without obstacle. The results demonstrate that our needle steering strategy guides the needle to the desired targets with the maximum error of 2.85mm.

  34. M. Waine, C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - Needle tracking and deflection prediction for robot-assisted needle insertion using 2D ultrasound images. In the Journal of Medical Robotics Research (JMRR), vol 1, no. 1, 2016. 10.1142/S2424905X16400018 ( pdf) BibTeX

    @Article{Waine2016a,
    author = {Waine, Michael and Rossa, Carlos and Sloboda, Ron and Usmani, Nawaid and Tavakoli, Mahdi},
    title = {Needle Tracking and Deflection Prediction for Robot-Assisted Needle Insertion Using 2D Ultrasound Images},
    journal = {Journal of Medical Robotics Research},
    volume = {01},
    number = {01},
    pages = {1640001},
    year = {2016},
    doi = {10.1142/S2424905X16400018},
    URL = {http://www.worldscientific.com/doi/abs/10.1142/S2424905X16400018},
    eprint = {http://www.worldscientific.com/doi/pdf/10.1142/S2424905X16400018}
    }

    Abstract

    In many types of percutaneous needle insertion surgeries, tissue deformation and needle deflection can create significant difficulties for accurate needle placement. In this paper, we present a method for automatic needle tracking in 2D ultrasound (US) images, which is used in a needle–tissue interaction model to estimate current and future needle tip deflection. This is demonstrated using a semi-automatic needle steering system. The US probe can be controlled to follow the needle tip or it can be stopped at an appropriate position to avoid tissue deformation of the target area. US images are used to fully parameterize the needle-tissue model. Once the needle deflection reaches a pre-determined threshold, the robot rotates the needle to correct the tip’s trajectory. Experimental results show that the final needle tip deflection can be estimated with average accuracies between 0.7mm and 1.0mm for insertions with and without rotation. The proposed method provides surgeons with improved US feedback of the needle tip deflection and minimizes the motion of the US probe to reduce tissue deformation of the target area.

  35. C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - Estimating needle tip deflection in biological tissue from a single transverse ultrasound image: Application to brachytherapy. In The International Journal of Computer Assisted Radiology and Surgery (IJCARS), vol 11, no. 7, pp 1347-1359, 2015. 10.1007/s11548-015-1329-4 ( pdf) BibTeX

    @Article{Rossa2016d,
    author={Rossa, Carlos and Sloboda, Ron and Usmani, Nawaid and Tavakoli, Mahdi},
    title={Estimating needle tip deflection in biological tissue from a single transverse ultrasound image: application to brachytherapy},
    journal={International Journal of Computer Assisted Radiology and Surgery},
    year={2016},
    volume={11},
    number={7},
    pages={1347--1359},
    issn={1861-6429},
    doi={10.1007/s11548-015-1329-4},
    url={http://dx.doi.org/10.1007/s11548-015-1329-4}}

    Abstract

    This paper proposes a method to predict the deflection of a flexible needle inserted into soft tissue based on the observation of deflection at a single point along the needle shaft. We model the needle-tissue as a discretized structure composed of several virtual, weightless, rigid links connected by virtual helical springs whose stiffness coefficient is found using a pattern search algorithm that only requires the force applied at the needle tip during insertion and the needle deflection measured at an arbitrary insertion depth. Needle tip deflections can then be predicted for different insertion depths. Verification of the proposed method in synthetic and biological tissue shows a deflection estimation error of 2 mm for images acquired at 35 % or more of the maximum insertion depth, and decreases to 1 mm for images acquired closer to the final insertion depth. We also demonstrate the utility of the model for prostate brachytherapy, where in vivo needle deflection measurements obtained during early stages of insertion are used to predict the needle deflection further along the insertion process. The method can predict needle deflection based on the observation of deflection at a single point. The ultrasound probe can be maintained at the same position during insertion of the needle, which avoids complications of tissue deformation caused by the motion of the ultrasound probe

  36. M. Waine, C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - Three-Dimensional needle shape estimation in TRUS-guided prostate brachytherapy using 2D ultrasound images. In IEEE Journal of Biomedical and Health Informatics (J-BHI), vol 20, no 6, pp 1621-1631, 2016. 10.1109/JBHI.2015.2477829 ( pdf) BibTeX

    @Article{Waine2016c,
    author={M. Waine and C. Rossa and R. Sloboda and N. Usmani and M. Tavakoli},
    journal={IEEE Journal of Biomedical and Health Informatics},
    title={Three-Dimensional Needle Shape Estimation in TRUS-Guided Prostate Brachytherapy Using 2D Ultrasound Images},
    year={2016},
    volume={6},
    number={20},
    pages={1621-1631},
    doi={10.1109/JBHI.2015.2477829},
    ISSN={2168-2194},
    month={Nov},}

    Video

    Abstract

    In this paper we propose an automated method to reconstruct the 3D needle shape during needle insertion procedures using only 2D transverse ultrasound (US) images. Using a set of transverse US images, image processing and random sample consensus (RANSAC) is used to locate the needle within each image and estimate the needle shape. The method is validated with an in-vitro needle insertion setup and a transparent tissue phantom, where two orthogonal cameras are used to capture the true 3D needle shape for verification. Results showed that the use of at least 3 images obtained at 75% of the maximum insertion depth or greater allows for maximum needle shape estimation errors of less than 2 mm. In addition, the needle shape can be calculated consistently as long as the needle can be identified in 30% of the transverse US images obtained. Application to permanent prostate brachytherapy (PPB) is also presented, where the estimated needle shape is compared to manual segmentation and sagittal US images. Our method is intended to help assess needle placement during manual or robotassisted needle insertion procedures after the needle has been inserted.

  37. C. Rossa, J. Lozada, and A. Micaelli - Design and control of a dual unidirectional brake hybrid actuation system for haptic interfaces. In IEEE Transactions on Haptics. Vol 7, no 4, pp 442-453, 2014. 10.1109/TOH.2014.2346501 ( pdf)
    BibTeX

    @Article{Rossa2014a,
    author={C. Rossa and J. Lozada and A. Micaelli},
    journal={IEEE Transactions on Haptics},
    title={Design and Control of a Dual Unidirectional Brake Hybrid Actuation System for Haptic Devices},
    year={2014},
    volume={7},
    number={4},
    pages={442-453},
    doi={10.1109/TOH.2014.2346501},
    ISSN={1939-1412},
    month={Oct},}

    Abstract

    Hybrid actuators combining brakes and motors have emerged as an efficient solution to achieve high performance in haptic devices. In this paper, an actuation approach using two unidirectional brakes and a DC motor is proposed. The brakes are coupled to overrunning clutches and can apply a torque in only one rotational direction. The associated control laws, that are independent of the virtual environment model, calculate the control gains in real time in order limit the energy and the stiffness delivered by the motor to ensure stability. The reference torque is respected using the combination of the motor and the brake. Finally, an user experiment has been performed to evaluate the influence of passive and active torque differences in the perception of elasticity. The proposed actuator has a torque range of 0.03 Nm to 5.5 Nm with a 17.75 kNm-2 torque density.

  38. C. Rossa, A. Jaegy, A. Micaelli, and J. Lozada - Design considerations for magnetorheological brakes. In IEEE/ASME Transactions on Mechatronics. Vol 19, no. 5, 2014. 10.1109/TMECH.2013.2291966 ( pdf) BibTeX

    @Article{Rossa2014b,
    author={C. Rossa and A. Jaegy and J. Lozada and A. Micaelli},
    journal={IEEE/ASME Transactions on Mechatronics},
    title={Design Considerations for Magnetorheological Brakes},
    year={2014},
    volume={19},
    number={5},
    pages={1669-1680},
    doi={10.1109/TMECH.2013.2291966},
    ISSN={1083-4435},
    month={Oct},}

    Abstract

    Design considerations for magnetorheological (MR) brakes are discussed for different geometries. A complete modeling in terms of torque density, efficiency, bandwidth, and controllability is presented. The model assigns a desired magnetic flux density over the fluid surface. The magnetic circuit dimensions and the necessary power can be calculated in consequence. The analysis focuses on a single disc and on a single drum brake and highlights the interdependence of the measures of performance as a function of the dimensions. The proposed models have been validated using finite-element analysis, the results demonstrate that both brakes are equivalent in terms of torque density but drum brakes are more reactive and require less power. The analysis has subsequently been extended to multiple-layered brakes with several fluid gaps in parallel. The performance are globally improved by increasing the number of gaps. Finally, the paper considers the influence of the MR fluid characteristics and housing material.

  39. C. Rossa, A. Jaegy, J. Lozada, and A. Micaelli - Development of a multilayered wide-raged torque magnetorheological brake. In Smart Material and Structures. Vol 23, no. 2. 025028, 2014. 10.1088/0964-1726/23/2/025028 ( pdf) BibTeX

    @Article{Rossa2014c,
    author={Carlos Rossa and Adrien Jaegy and Alain Micaelli and José Lozada},
    title={Development of a multilayered wide-ranged torque magnetorheological brake},
    journal={Smart Materials and Structures},
    volume={23},
    number={2},
    pages={025028},
    url={http://stacks.iop.org/0964-1726/23/i=2/a=025028},
    year={2014},}

    Abstract

    This paper presents the design of a multilayered magnetorheological brake from modelling to prototyping and characterization. A magnetostatic model intended to provide a specific magnetic flux density over a fluid gap regardless of the dimensions of the fluid surface is proposed. The ferromagnetic path and the coil are dimensioned in consequence. The model needs only three inputs to completely define the brake, i.e. the number of fluid gaps, the inner radius of the smallest fluid gap and the fluid gap depth. The evaluation criteria are defined by the torque density, the controllability and the reactivity, described as a function of the dimensions and the number of fluid gaps. The model has been optimized to improve the torque density. The brake has four fluid gaps and has been built and characterized. The expected torque when the fluid reaches the desired induction is 3.4 N m and the measured torque is 3.6 N m. This represents a relative error of 5.5%. The brake has 60 mm diameter, 39 mm width with a hollow shaft of 12 mm diameter. When exploited up to complete saturation, the measured torque is 5.3 N m with 19 W power consumption. The brake has a torque density of 48.1 kN m−2 and a maximum-to-minimum torque ratio of 176, with 50 ms electromechanical time constant.

  40. C. Rossa, L. Eck, J. Lozada, and A. Micaelli - On a novel torque detection technique for magnetorheological actuators. In IEEE Sensors Journal. Vol 14, no. 4, pp 1223-1231, 2014. 10.1109/JSEN.2013.2287730 ( pdf) BibTeX

    @Article{Rossa2013a,
    author={C. Rossa and L. Eck and A. Micaelli and J. Lozada},
    journal={IEEE Sensors Journal},
    title={On a Novel Torque Detection Technique for Magnetorheological Actuators},
    year={2014},
    volume={14},
    number={4},
    pages={1223-1231},
    doi={10.1109/JSEN.2013.2287730},
    ISSN={1530-437X},
    month={April},}

    Abstract

    This paper focuses on a new torque detection technique for magnetorheological (MR) actuators. An MR fluid consists of a suspension of ferromagnetic micrometer-sized particles in a carrier fluid. Under the action of a magnetic field, these particles form chain-like structures that interact with the magnetic poles. The torque detection technique is based on the assumption that a relative displacement of the poles stretches the chains, altering the magnetic reluctance of the fluid gap. This hypothesis is analytically developed using an elementary group of ferromagnetic particles placed in a nonmagnetic carrier liquid. A measure of the excitation coil impedance using a high precision demodulator, is used to verify this hypothesis. Experimental results show that when the poles are displaced before the rupture of the chains, the chains are stretched and the reluctance increases. A higher sensitivity system is subsequently proposed to detect the variation of an external torque. The experimental results demonstrate that the system is able to detect the application as well as the release of the torque and can successfully be employed to detect the chain rupture critical point.

Conference papers | Conférences internationales
  1. O. Wilz, B. Sainsbury, and C. Rossa - Multiobjective Path Planning for Autonomous Robotic Percutaneous Nephrolithotomy via Discrete B-spline Interpolation. IEEE International Conference on Systems, Man, and Cybernetics, Melbourne, Australia, 2021. accepted BibTeX

    Bientôt disponible

    Abstract

    Percutaneous nephrolithotomy is the leading treatment for large or irregularly shaped kidney stones. Nevertheless, gaining access to the kidney remains a challenging component of the procedure with a steep learning curve. As a result, the procedure would benefit from robotic assistance to partially or fully automate this critical component of the intervention. A key component of automated kidney access, using a robotic manipulator, is to define and follow a tool path planning based on preoperative imaging and a target entry point. In this paper, the use of the multiobjective non-dominated sorting genetic algorithm II (NSGA-II) is proposed to plan a Bspline curve that will be used as the tool trajectory during the procedure. Here, NSGA-II is used to determine the anchor point locations for a uniform 3rd order B-spline curve. The optimal path minimizes path length, tissue potential energy due to tissue compression, and path smoothness while maximizing the distance to obstacles. The multiobjective optimization is evaluated using simulations and physical trials. The results show that the planned trajectories show minimal tissue deformation, are relatively short and smooth and do not collide with the internal kidney structures.

  2. B. Kent, M. Lacki, and C. Rossa - A Modified Forward Stepwise Classifier for Failure Mode Detection from Robot Sensor Readings. IEEE International Conference on Systems, Man, and Cybernetics, Melbourne, Australia, 2021. accepted BibTeX

    Bientôt disponible

    Abstract

    One of the many challenges in autonomous robots is that they can enter an error state and are unable to continue operation without human intervention. Sensors installed on the robot enable proprioception and could help the robot understand its error configuration. This paper proposes a method to determine from these sensor measurements, which are most critical in differentiating the error states such that the robot could understand its predicament, and could therefore attempt at recovering without human aid. A classification model is built using the forward stepwise method and a scoring metric to overcome indecision in choosing between different features. This modified method is applied to three robot operating mode data sets. The experiments indicate an improvement to the classifier performance when using this the model built by the method compared to using all available predictor variables. With further refinement, this scoring metric could be a simple yet effective way to build classification models for increasing robot autonomy.

  3. B. DeBoer, A. Hosseini, and C. Rossa - An Extended Parameter Estimation Disturbance Observer for an Active Ankle Foot Orthosis. IEEE International Conference on Systems, Man, and Cybernetics, Melbourne, Australia, 2021. accepted
    BibTeX

    Bientôt disponible

    Abstract

    An active ankle foot orthosis (AAFO) is an assistive device that applies plantarflexion and dorsiflexion assistance to the ankle joint by means of a compliant actuator. The device must apply sufficient torque assistance to track a desired ankle trajectory. However, torque disturbances are prevalent throughout the gait cycle. Accurately modelling the AAFO in conjunction with the ankle joint disturbance torque is a difficult task, as the model parameters can change over time. As a result, parameters such as inertia and friction are often roughly estimated based on the user’s weight. The uncertainties due to unmodelled disturbances and error in dynamics modelling, can severely compromise the device’s ability to provide appropriate assistance.
    This paper presents a novel extended parameter estimation observer combined with a disturbance rejection controller to estimate the model’s inertia and friction. First, an extended state observer (ESO) is employed in which the extended state is the estimated disturbance. Knowing the nominal ankle torque trajectory and the disturbance, a novel control law is formulated to reject the effects of endogenous disturbance torque during trajectory tracking. Then, based on the observed difference between the observed disturbance and nominal ankle torque, the paper introduces a novel method to estimate the inertial and friction parameters of the AAFO.
    Simulation results show that state feedback with the ESO is able to reduce the root mean square tracking error by 8.8% and 71.1% for high and low feedback gains, respectively. The results also indicate that the estimated AAFO and ankle joint inertial and damping parameters converges to the nominal plant parameters. Simulations also show the effectiveness of the estimation laws from various initial plant estimates.smooth and do not collide with the internal kidney structures.

  4. B. DeBoer, C. McDermott, A. Hosseini, and C. Rossa - Reference Point-Based Particle Sub-Swarm Optimization. IEEE International Conference on Systems, Man, and Cybernetics, Melbourne, Australia, 2021. accepted
    BibTeX

    Bientôt disponible

    Abstract

    In this paper, a novel optimization method named reference point-based particle sub-swarm optimization (RPBPSWO) is presented; combining particle swarm optimization (PSO) with the non-dominated sorting genetic algorithm II (NSGA-II). PSO is an inexpensive mono-objective optimizer that performs well in optimization problems with a high number of decision variables. NSGA-II is a multi-objective optimizer that selects the best and diverse solutions to guide the optimization. RPB-PSWO combines the traveling method of PSO and with the non-dominance and diversity selection methods of NSGA-II. The multi-objective optimizer is equipped with a reference point-based system to allocate particles into a sub-swarm, in which particles are attracted to a pareto optimal solution in that sub-swarm. To encourage diversity and avoid local minima a density and turbulence factor was incorporated to alter the positions of the particles. The developed RPB-PSWO is designed for optimization problems with many dependent variables, as the position update method of PSO inherently preserves dependent relationships. The proposed algorithm, although less computationally efficient than NSGA-II, is capable of creating diverse pareto front solutions for standardized and custom optimization problems. To analyze the proposed algorithm, the Zitzler–Deb–Thiele test set and a real world optimization problem of designing an actuation system for an ankle foot orthosis were explored. The results show that RPB-PSWO outperforms NSGA-II based on the rate of convergence, but under preforms with respect to computational time. Additionally, RPB-PSWO proved its effectiveness by converging at a faster rate when dependant variables were present.

  5. O. Wilz, B. Kent, B. Sainsbury, and C. Rossa - Multiobjective trajectory tracking of a flexible tool during robotic percutaneous nephrolithotomy. IEEE International Conference on Intelligent Robots and Systems, Prague, Czech Republic, 2021, accepted for presentation, to be published in IEEE Robotics and Automation Letters BibTeX

    Bientôt disponible

    Abstract

    Percutaneous Nephrolithotomy (PCNL) is the leading intervention for removing large or irregularly shaped kidney stones. It involves gaining access to the kidney through a small incision in the patient’s back, through which a nephroscope is steered towards the stones. Despite decades of clinical prevalence, PCNL remains a complex procedure to learn and perform, sometimes requiring several attempts to gain kidney access , leading to a variety of complications. This paper proposes to use robotic assistance to steer a flexible nephroscope during PCNL to concurrently improve accuracy and reduce the risk of tissue damage. The nephroscope is modelled as a cantilever beam fixed to the robot’s end-effector. Under the assumption that an optimal tooltip path exists, Non-dominated Sorting Genetic AlgorithmII is implemented to determine the end-effector position and orientation so that the tooltip follows the path while minimizing four objective functions, i.e., tissue compression, variations in the tool’s strain energy, changes in end-effector position, and tooltip error. Data collected through experiments performed on ex-vivo porcine tissue show that the path tracking error was on average 2.03 mm. The results confirm the accuracy of the model in 2 dimensions and suggest that the multiobjective optimizer returned adequate solutions that minimized 4 different cost functions, altogether allowing the robot to effectively follow the predefined path.

  6. R. Tan, and C. Rossa - Electrical impedance tomography using differential evolution integrated with a modified Newton-Raphson algorithm. IEEE International Conference on Systems, Man, and Cybernetics, Toronto, Canada, Oct 2020, ( pdf)
    10.1109/SMC42975.2020.9282957 BibTeX

    @INPROCEEDINGS{Tan2020,
    author={R. Tan, and C. Rossa},
    booktitle={IEEE International Conference on Systems, Man, and Cybernetics},
    title={Electrical impedance tomography using differential evolution integrated with a modified Newton-Raphson algorithm},
    year={2020},
    pages={2528-2534},
    doi={10.1109/SMC42975.2020.9282957},
    month={Oct},}

    Abstract

    Electrical impedance tomography (EIT) is a noninvasive medical imaging procedure. Image reconstruction in EIT is difficult because it involves solving a non-linear and ill-posed mathematical problem. One of the most commonly implemented inverse approaches is usually a variation of the Newton Raphson algorithm. However, this approach is not guaranteed to reach a global optimum or a local optimum and as such, it requires an accurate initial estimation of the resistance distribution, which is not always available in practice.
    In this paper, a new method is proposed to solve for the inverse problem in EIT while avoiding dependencies on the initial estimation of the resistance distribution. The proposed approach uses a differential evolution (DE) optimizer integrated with the Newton Raphson algorithm. The stochastic nature of DE allows the problem to be solved without having an accurate initial estimation and allows for solutions that will not be trapped in local minimal values. Simulation results indicate that the proposed approach outperforms the traditional differential evolution algorithm, and performs similarly to the traditional Modified Newton Raphson algorithm with accurate initial estimation. The proposed method does, however, have an advantage over the Modified Newton Raphson algorithm as it does not require an estimate of the initial resistance distribution.

  7. B. Kent, and C. Rossa - Tissue discrimination from impedance spectroscopy as a multi-objective optimisation problem with weighted Naive Bayes classification. IEEE International Conference on Systems, Man, and Cybernetics, Toronto, Canada, Oct 2020, ( pdf) 10.1109/SMC42975.2020.9283266 BibTeX

    @INPROCEEDINGS{Kent2020,
    author={B. Kent, and C. Rossa},
    booktitle={IEEE International Conference on Systems, Man, and Cybernetics},
    title={Tissue discrimination from impedance spectroscopy as a multi-objective optimisation problem with weighted Naive Bayes classification},
    year={2020},
    pages={321-327},
    doi={10.1109/SMC42975.2020.9283266},
    month={Oct},}

    Abstract

    Tissue classification from electrical impedance spectroscopy has several applications in diagnosis, surgical planning, and minimally invasive surgery. The method involves applying an alternating current to the sample and measuring its electric impedance at various frequencies. The spectrum is fit to a equivalent electric circuit that mimics the shape of the tissue's impedance spectrum. The model parameters are then used for classification.
    This paper proposes a new solution to decompose the model fitting problem into a form suitable for multi-objective optimisation, from which all the non-dominated solutions are used to form the database of parameters for a given tissue, as opposed to a single solution that is typically seen in impedance spectroscopy. The solution explores the use of the reference point dominance condition within Non-dominated Sorting Genetic Algorithm II to fit the data to the double dispersion Cole model. Each nondominated solution contain values for the dispersion model elements. The multiple parameter value solutions from the optimiser are used as features in a weighted Naive Bayes classifer to identify a new tissue sample. Experiments results in 3 different tissue samples shows that the method is successful in correctly labelling the data with an average accuracy of 89\%.

  8. B. DeBoon, S. Nokleby, and C. Rossa - Backlash-compensated active disturbance rejection control of nonlinear multi-input series elastic actuators. International Conference on Robotics and Automation (ICRA), pp. 6183-6189, Paris, France, May 2020. ( pdf) 10.1109/ICRA40945.2020.9196657 BibTeX

    @INPROCEEDINGS{DeBoon2020,
    author={B. DeBoon, S. Nokleby, and C. Rossa},
    booktitle={International Conference on Robotics and Automation},
    title={Backlash-compensated active disturbance rejection control of nonlinear multi-input series elastic actuators.},
    year={2020},
    pages={6183-6189},
    doi={10.1109/ICRA40945.2020.9196657},
    month={May},}

    Abstract

    Series elastic actuators with passive compliance have been gaining increasing popularity in force-controlled robotic manipulators. One of the reasons is the actuator’s ability to infer the applied torque by simply measuring the deflection of the elastic element as opposed to direct torque measurement. Proper deflection control is pinnacle to achieve a desired output torque and, therefore, small deviances in positional measurements or a nonlinear deformation can have adverse effects on performance. In applications requiring relatively large torques, the actuators typically use gear reductions which inherently result in mechanical backlash or play. This combined with the nonlinear behaviour of the elastic element and unmodelled dynamics, can severely compromise force fidelity.
    This paper proposes a backlash compensating active disturbance rejection controller (ADRC) for multi-input series elastic actuators. In addition to proper deflection control, a multiinput active disturbance rejection controller is derived and implemented experimentally to mitigate any unmodelled nonlinearities or perturbations to the plant model. The controller is experimentally validated on a hybrid motor-brake-clutch series elastic actuator and the controller performance is compared against traditional error-based controllers. It is shown that the backlash compensated ADRC outperforms classical PID and ADRC methods and is a viable solution to positional measurement error in elastic actuators.

  9. M. Lacki, B. DeBoon, and C. Rossa - Impact of kinematic structure on the force displayability of planar passive haptic devices. Presented at 2020 Haptics Symposium and published in IEEE Transactions on Haptics, vol. 13, no. 1, pp. 219-225, 2020. 10.1109/TOH.2020.2970906 (pdf) BibTeX

    @Article{Lacki2020,
    author={M. Lacki and B. DeBoon and C. Rossa},
    journal={IEEE Transactions on Haptics},
    title={Impact of kinematic structure on the force displayability of planar passive haptic devices},
    year={2020},
    volume={13},
    pages={219-225},
    doi={10.1109/TOH.2020.2970906},
    ISSN={1939-1412},
    }

    Abstract

    Haptic devices containing passive actuators, such as controllable brakes or dampers, are an attractive alternative to their motor-driven counterparts due to intrinsic stability and improved impedance bandwidth. Passive actuators cannot generate energy, and, therefore, the output force can only oppose the applied velocity. In the same way the kinematic structure of traditional manipulators is designed to maximize dexterity and manipulability, one must consider adapting the device topology to optimize force displayability when designing passive actuators.
    This paper introduces a set of metrics to evaluate and compare the performance of 2-degree-of-freedom serial and parallel passive haptic devices. These metrics consider the impact of the kinematic structure on the force displayability of 9 unique configurations. It is shown that: 1.) Serial manipulators can generate passive forces in all directions equally regardless of the link length ratio; 2.) The base link length of 5-bar parallel manipulators strongly influences passive force displayability; and 3.) 5-bar parallel manipulators with the base link length of zero can generate the widest range of passive forces when all links have the same length. The novel performance metrics presented in this paper can aid in the design of 2-DOF passive haptic devices.

  10. B. Kent, A. Cusipag, and C. Rossa - Tissue discrimination through force-feedback from impedance spectroscopy in robot-assisted surgery. International Conference on Smart Multimedia, San Diego, Dec 2019, accepted (pdf) BibTeX

    @INPROCEEDINGS{Kent2019,
    author={B. Kent, A. Cusipag, and C. Rossa},
    booktitle={International Conference on Smart Multimedia, 2019},
    title={Tissue discrimination through force-feedback from impedance spectroscopy in robot-assisted surgery},
    year={2019},
    pages={},
    doi={},
    month={Dec},}

    Abstract

    Haptic force feedback in teleoperated robot-assisted minimally invasive surgery is diffcult to implement with traditional force sensors at the tool tip. A novel approach to displaying forces to the user is explored using electric impedance spectroscopy with an electrode embedded needle. To give substance to the proposed method, user trials were conducted to compare the accuracy of inserting needles by hand and through electric impedance based haptic teleoperation. The results of the experiment suggest that, when compared to the control scenario, novice operators could accurately locate the phantom tumour with a high degree of accuracy and repeatability using force feedback derived from electric impedance spectroscopy.

  11. B. DeBoon, B. Kent, M. Lacki, S. Nokleby, and C. Rossa - Multi-objective gain optimizer for an active disturbance rejection controller. IEEE Global Conference on Signal and Information Processing, Ottawa, Canada, Nov 2019, 10.1109/GlobalSIP45357.2019.8969275 (pdf) BibTeX

    @INPROCEEDINGS{DeBoon2019b,
    author={B. DeBoon, B. Kent, M. Lacki, S. Nokleby, and C. Rossa},
    booktitle={IEEE International Global Conference on Signal and Information Processing },
    title={Multi-objective gain optimizer for an active disturbance rejection controller,
    year={2019},
    pages={},
    doi={10.1109/GlobalSIP45357.2019.8969275},
    month={Nov},}

    Abstract

    Active Disturbance Rejection Control (ADRC) has proven to be an efficient control method, however, the tuning of its parameters is a complicated endeavor. This paper explores the use of reference point based dominance in the traditional multiobjective non-dominated sorting genetic algorithm (NSGA-II) to perform the parameter tuning. The algorithm is applied to a simulation and physical implementation of an inverted pendulum system. The optimization method generated values that offered suitable performance among various fronts.

  12. M. Lacki, and C. Rossa - On the feasibility of multi-degree-of-freedom haptic devices using passive actuators. IEEE/RSJ Inter. Conference on Intelligent Robots and Systems (IROS), pp. 7282-7287, Macau, Nov 2019. 10.1109/IROS40897.2019.8968164 (pdf) BibTeX

    @INPROCEEDINGS{Lacki2019,
    author={M. Lacki, and C. Rossa},
    booktitle={IEEE International Conference on Intelligent Robots and Systems},
    title={On the feasibility of multi-degree-of-freedom haptic devices using passive actuators},
    year={2019},
    pages={7282-7287},
    doi={978-1-7281-4003-2},
    month={Nov},}

    Abstract

    Stability and transparency are key design requirements in haptic devices. Transparency can be significantly improved by replacing convectional electric motors with passive actuators such as brakes or dampers. Passive actuators can display a wide range of impedance and since they can only dissipate energy, stability is guaranteed. However, passive haptic devices suffer from a serious drawback: the direction of the force output is difficult to control. This issue has been addressed extensively for planar manipulators but devices with higher degrees-of-freedom (DOF) have not been examined.

    In this paper, we introduce a new analytical framework to evaluate the feasibility and performance of non-redundant passive haptic manipulators with any DOF. The method identifies different regions in the workspace where a force can be created or approximated, and regions where a passive system cannot create force at all for a given user input. The results indicate that the range of forces a passive device can display increases with the number of DOF. The proposed framework can be used as a valuable tool to aid in the design of control methods for multi-DOF passive haptic devices.

  13. B. DeBoon, S. Nokleby, N. La Delfa, and C. Rossa - Differentially-clutched series elastic actuator for robot-aided musculoskeletal rehabilitation. IEEE International Conference on Robotics and Automation (ICRA), Montréal, Canada, pp. 1507-1513, May 2019. 10.1109/ICRA.2019.8793586 (pdf) BibTeX

    @INPROCEEDINGS{Deboon2019a,
    author={B. DeBoon and S. Nokleby and N. La Delfa and C. Rossa},
    booktitle={IEEE International Conference on Robotics and Automation},
    title={Differentially-clutched series elastic actuator for robot-aided musculoskeletal rehabilitation},
    year={2019},
    pages={1507-1513},
    doi={10.1109/ICRA.2019.8793586},
    month={May},}

    Abstract

    Series elastic actuators have proven to be an elegant response to the issue of safety around human-robot interaction. The compliant nature of series elastic actuators provides the potential to be applied in robot-aided rehabilitation for patients with upper and lower limb musculoskeletal injuries.
    This paper proposes a new series elastic actuator to be used in robot-aided musculoskeletal rehabilitation. The actuator is composed of a DC motor, a torsion spring, and a magnetic particle brake coupled to one common output shaft through a differential gear. The proposed topology focuses on three types of actuation modes most commonly used in rehabilitation, i.e., free motion, elastic, and assistive/resistive motion. A dynamic model of the actuator is presented and validated experimentally and the ability of the actuator to follow a reference torque is shown in different experimental scenarios.

  14. C. Rossa, M. Najafi, M. Tavakoli, and K. Adams - Nonlinear workspace mapping for telerobotic assistance of upper limb in patients with severe movement disorders. IEEE International Conference on Systems, Man, and Cybernetics, Banff, Canada, pp. 2255-2260, Oct 2017. 10.1109/SMC.2017.8122956 ( pdf) BibTeX

    @INPROCEEDINGS{RossaSMC2017,
    author={C. Rossa and M. Najafi and M. Tavakoli and K. Adams},
    booktitle={IEEE International Conference on Systems, Man, and Cybernetics},
    title={Nonlinear workspace mapping for telerobotic assistance of upper limb in patients with severe movement disorders},
    year={2017},
    pages={2255-12260},
    doi={978-1-5386-1644-4},
    month={Oct},}

    Abstract

    Telerobotic manipulation allows patients living with upper limb impairments to interact with a variety of environments and accomplish through teleoperation daily activities such as playing, feeding, self-care, and leisure, that would otherwise be difficult to perform. In this paper, we propose a nonlinear mapping between the patient’s range of motion and the workspace of an environment being manipulated. The objective is to identify the patient’s workspace and span it to that of the environment or an object, thus optimizing the scaling factor while soliciting the entire patient’s range of motion. The boundaries of each workspace are obtained from scattered measurements of the master and slave robots end-effector position. The nonlinear mapping is then achieved through thin plate spline interpolation that describes deformation between two surfaces by scattered point-to-point preponderances. Experimental results reported in three different scenarios confirm the suitability of the nonlinear transformation to map diverse workspace volumes.

  15. M. Khadem, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - Feedback-linearization-based 3D needle steering in a Frenet-Serret frame using a reduced order bicycle model. American Control Conference, Seattle, USA, pp. 1438-1443, May 2017. (Best student paper award finalist). 10.23919/ACC.2017.7963155 ( pdf) BibTeX

    @INPROCEEDINGS{KhademACC2017,
    author={M. Khadem and C. Rossa and N. Usmani and R. Sloboda and M. Tavakoli},
    booktitle={2017 American Control Conference},
    title={Feedback-Linearization-based 3D Needle Steering in a Frenet-Serret Frame Using a Reduced Order Bicycle Model},
    year={2017},
    pages={1438-1443},
    doi={978-1-5090-5994-2},
    month={May},}

    Abstract

    Robotics-assisted needle steering can enhance the performance of needle-based clinical procedures such as biopsy, brachytherapy, and drug delivery. We present an automated needle steering system capable of steering needles in 3D toward targets in tissue while avoiding anatomical obstacles. The system comprises a nonholonomic model of needle steering in tissue and a nonlinear controller for 3D trajectory tracking in soft tissue. First, a new reduced-order model of needle steering is presented. The proposed model is fully controllable and all the system states can be estimated on the fly. Next, the model is transformed to a local coordinate system using the Serret- Frenet formulation. By means of this transformation, the needle steering problem is converted to the regulation of the distance of the needle tip from a desired 3D trajectory. Finally, using the transformed model, a novel nonlinear controller is developed to steer the needle in 3D while avoiding anatomical obstacles. The control strategy is validated through simulations. The simulations indicate that the system is stable and can successfully follow a 3D trajectory. The results are promising, enabling future research in flexible needle path planning and control using the proposed reduced-order model and the controller.

  16. C. Rossa, M. Khadem, N. Usmani, R. Sloboda, and M. Tavakoli - Constrained optimal control of needle deflection for semi-manual steering. IEEE International Conference on Advanced Intelligent Mechatronics, Banff, Canada, Jul 2016. 10.1109/AIM.2016.7576933 ( pdf) BibTeX

    @INPROCEEDINGS{Rossa2016e,
    author={C. Rossa and M. Khadem and R. Sloboda and N. Usmani and M. Tavakoli},
    booktitle={2016 IEEE International Conference on Advanced Intelligent Mechatronics (AIM)},
    title={Constrained optimal control of needle deflection for semi-manual steering},
    year={2016},
    pages={1198-1203},
    doi={10.1109/AIM.2016.7576933},
    month={July},}

    Abstract

    Brachytherapy is a widely used treatment for patients with localized cancer where high doses of radiation are administered to cancerous tissue by implanting radioactive seeds into the prostate using long beveled-tip needles. Accurate seed placement is an important factor that influences the outcome of the treatment. In this paper, we present and study the suitability of a new framework for computer-assisted needle steering during seed implantation in brachytherapy. The framework is based on a hand held brachytherapy needle steering apparatus. As the needle is manually inserted, the device automatically rotates the needle's base axially at appropriate depths inside tissue in order to control the trajectory of the needle tip towards a target. The steering controller is based on the Rapidly Exploring Random Tree algorithm that updates the necessary manoeuvres online. Experimental results performed in phantom and ex-vivo biological tissues show an average absolute targeting error of 0.56 ±0.62 and 0.48 ±0.48 mm, respectively.

  17. M. Waine, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - An integrator-backstepping control approach for out-of-plane needle deflection minimization. IEEE International Conference on Advanced Intelligent Mechatronics, Banff, Canada, Jul 2016. 10.1109/AIM.2016.7576998 ( pdf) BibTeX

    @INPROCEEDINGS{Waine2016e,
    author={M. Waine and C. Rossa and N. Usmani and R. Sloboda and M. Tavakoli},
    booktitle={2016 IEEE International Conference on Advanced Intelligent Mechatronics (AIM)},
    title={An integrator-backstepping control approach for out-of-plane needle deflection minimization},
    year={2016},
    pages={1598-1603},
    doi={10.1109/AIM.2016.7576998},
    month={July},}

    Video

    Abstract

    In this paper, we develop a needle steering strategy designed to reduce the out-of-plane deflection of a flexible, bevel-tipped needle for clinical needle insertion applications. This is performed through an integrator-backstepping approach. Integrator-backstepping is a nonlinear feedback controller design that divides the entire system into a sequence of smaller design problems that are easier to manage. Simulations were performed to observe the effects of our controller design on the system's response, specifically the rate at which the out-of-plane deflection converges. We tested our proposed method using a biological tissue phantom composed of two separate heterogeneous layers and using an 18 gauge brachytherapy needle. A paired-sample t-test was performed to compare out-of-plane needle deflection results with and without the use of our needle steering algorithm under varying bevel-angle starting conditions. Results showed a significant decrease in the out-of-plane needle deflection with the use of our controller at the 1% significance level. The absolute-mean out-of-plane needle deflection at a depth of 140 mm changed from 7.1 mm to 0.7 mm with the implementation of our needle steering approach. Our proposed steering method does not require “drilling” motions often encountered in duty-cycling controllers, and has been shown to be effective for clinical needles travelling through multiple heterogeneous tissue layers.

  18. M. Khadem, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - Introducing notched flexible needles with increased deflection curvature in soft tissue. IEEE International Conference on Advanced Intelligent Mechatronics, Banff, Canada, Jul 2016. 10.1109/AIM.2016.7576931 ( pdf) BibTeX

    @INPROCEEDINGS{Khadem2016e,
    author={M. Khadem and C. Rossa and N. Usmani and R. S. Sloboda and M. Tavakoli},
    booktitle={2016 IEEE International Conference on Advanced Intelligent Mechatronics (AIM)},
    title={Introducing notched flexible needles with increased deflection curvature in soft tissue},
    year={2016},
    pages={1186-1191},
    doi={10.1109/AIM.2016.7576931},
    month={July},}

    Abstract

    Robotics-assisted needle steering can enhance the accuracy of needle-based medical interventions, especially when the designated target locations are obscured by obstacles. However, the steering techniques using standard needles are not capable of achieving high curvatures and cannot follow tightly curved paths inside tissue. In this work, we introduce a new notched steerable needle with improved curvature. The notched needle is developed by carving a series of small notches on a regular needle shaft. The notches decrease the needle's flexural rigidity and increase the maximum achievable curvature. First, we develop a model of the notched needle deflection inside soft tissue using the finite element method (FEM). The model relates the needle radius of curvature to the number of notches and their locations on the needle shaft. Next, the capability of the notched steerable needle in achieving high curvature and the model's accuracy in predicting needle curvature are validated by performing several needle insertion experiments on a tissue phantom. The results demonstrate that our newly developed needles can achieve a minimum radius of curvature of 198 mm, which is 67% better than standard needles, enabling future research in needle steering in tight spaces.

  19. J. Carriere, C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - Real-time needle shape prediction in soft-tissue based on image segmentation and particle filtering. IEEE International Conference on Advanced Intelligent Mechatronics, Banff, Canada, Jul 2016. 10.1109/AIM.2016.7576934 (pdf) BibTeX

    @INPROCEEDINGS{Carriere2016a,
    author={J. Carriere and C. Rossa and R. Sloboda and N. Usmani and M. Tavakoli},
    booktitle={2016 IEEE International Conference on Advanced Intelligent Mechatronics (AIM)},
    title={Real-time needle shape prediction in soft-tissue based on image segmentation and particle filtering},
    year={2016},
    pages={1204-1209},
    doi={10.1109/AIM.2016.7576934},
    month={July},}

    Abstract

    Prostate brachytherapy is a current technique used to treat cancerous tissue in the prostate by permanently implanting radioactive seeds through the use of long flexible needles. This paper proposes a real-time method to predict the shape of a flexible needle inserted into soft tissue using axial Transrectal Ultrasound (TRUS) image segmentation and a non-holonomic bicycle model informed via particle filter. The needle location is tracked in TRUS images to capture the needle shape up to a specified depth. Through the use of a particle filter the noisy tracked needle shape is used to update the parameters of a kinematic bicycle model in a robust manner to predict the shape of the entire needle after it is fully inserted. The method is verified in both ex-vivo beef phantom tissue and in-vivo clinical images, yielding an average tip prediction error of less that 0.5 mm in both the ex-vivo and in-vivo image sets with a peak processing time of less than 9.5 ms per image frame.

  20. B. Fallahi, C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - Partial estimation of needle tip orientation in generalized coordinates in ultrasound image-guided needle insertion. IEEE International Conference on Advanced Intelligent Mechatronics, Banff, Canada, Jul 2016. 110.1109/AIM.2016.7576999 ( pdf) BibTeX

    @INPROCEEDINGS{Fallahi2016c,
    author={B. Fallahi and C. Rossa and R. Sloboda and N. Usmani and M. Tavakoli},
    booktitle={2016 IEEE International Conference on Advanced Intelligent Mechatronics (AIM)},
    title={Partial estimation of needle tip orientation in generalized coordinates in ultrasound image-guided needle insertion},
    year={2016},
    pages={1604-1609},
    doi={10.1109/AIM.2016.7576999},
    month={July},}

    Abstract

    In many subcutaneous needle insertion procedures, measuring needle deflection is necessary in order to accurately guide the needle towards inner body targets. Typically, needle deflection measurement are obtained from 2D ultrasound images, which can only provide the needle tip position, however, having knowledge about the needle tip heading (orientation) is very valuable in predicting the needle's future path for planning and needle steering reasons. Due to the small diameter of the needles and the low resolution of ultrasound imaging, the direct measurement of the needle tip orientation is not a trivial task. This paper represents a model-based non linear observer for partial estimating the needle tip orientation during needle insertion procedures using image-based position measurements. The proposed method employs a 3D kinematic unicycle model expressed in generalized coordinates. Applying nonlinear transformations on system states, the linearized transformed system equations are utilized in the observer design procedure. However, due to the singularities imposed by these transformations, certain assumptions are made for the convergence proof of the observer. The proposed observer is tested in simulations and experiments. In experiments, the observer is fed by the needle tip position measurements, which are obtained from real-time ultrasound images.

  21. T. Lehmann, C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - Needle path control during insertion in soft tissue using a force-sensor-based deflection estimator. IEEE International Conference on Advanced Intelligent Mechatronics, Banff, Canada, Jul 2016. 10.1109/AIM.2016.7576929 ( pdf) BibTeX

    @INPROCEEDINGS{Lehmann2016b,
    author={T. Lehmann and C. Rossa and R. Sloboda and N. Usmani and M. Tavakoli},
    booktitle={2016 IEEE International Conference on Advanced Intelligent Mechatronics (AIM)},
    title={Needle path control during insertion in soft tissue using a force-sensor-based deflection estimator},
    year={2016},
    pages={1174-1179},
    doi={10.1109/AIM.2016.7576929},
    month={July},}

    Abstract

    Needle insertion is commonly used in procedures such as prostate brachytherapy or biopsy. In prostate brachytherapy, the success of the procedure depends on the accurate placement of needles in their pre-planned target location. In order to steer the needle towards a defined target, past research has used ultrasound-image-based needle localization for needle tip position feedback. Acquiring and processing of ultrasound images, however, significantly limits the control sampling rate. This work proposes a method for needle path prediction and control without the need for image feedback. The needle tip path obtained during insertion from a force-sensor-based deflection estimator is used to parameterize a kinematic bicycle model. The bicycle model is then used to predict the needle tip path and the ideal rotation depth for reaching a desired target. Experimental results show that the introduced method accurately predicts the needle tip path and the ideal rotation depth to guide the needle to a pre-defined target.

  22. C. Rossa, J. Fong, N. Usmani, R. Sloboda, and M. Tavakoli - Multi-actuator haptic feedback on the wrist for needle steering guidance in brachytherapy. IEEE International Conference on Robotics and Automation, Stockholm, Sweden, 2016. Published in IEEE Robotics and Automation Letters. 10.1109/LRA.2016.2528295 ( pdf) BibTeX

    @Article{Rossa2016c,
    author={C. Rossa and J. Fong and N. Usmani and R. Sloboda and M. Tavakoli},
    journal={IEEE Robotics and Automation Letters},
    title={Multiactuator Haptic Feedback on the Wrist for Needle Steering Guidance in Brachytherapy},
    year={2016},
    volume={1},
    number={2},
    pages={852-859},
    doi={10.1109/LRA.2016.2528295},
    ISSN={2377-3766},
    month={July},}

    Video

    Abstract

    Brachytherapy is a cancer treatment procedure where long needles are inserted toward an inner body target in order to deliver radioactive seeds that treat the cancer cells. Controlling the trajectory of the needle is very challenging as it deviates from a straight path during insertion. In this letter, we present the pilot study of usefulness of a wristband with haptic feedback designed to help surgeons guide the needle toward a desired destination. The wristband embeds eight miniature actuators distributed around the wrist. The actuators are controlled to generate different haptic stimuli, each of which informs the user about a necessary needle steering manoeuvre. We describe the design of the wristband and its evaluation in two distinct user studies. In the first study, we evaluate how accurately users can identify the vibration patterns. In the second study, we focus on how the user responds to these patterns while performing needle insertion into tissue in an environment with high cognitive visual load. The reported average success rate in identifying the haptic pattern and the success rate in performing the correct action during needle insertion are 86% and 72%, respectively. These results suggest that the device could work in tandem with a needle steering algorithm to help surgeons achieve high quality implants and develop needle steering skills.

  23. B. Fallahi, M. Khadem, C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - Extended bicycle model for needle steering in soft tissue. IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2015), Hamburg, Germany, Oct 2015. 10.1109/IROS.2015.7353998 (pdf) BibTeX

    @INPROCEEDINGS{Fallahi2015a,
    author={B. Fallahi and M. Khadem and C. Rossa and R. Sloboda and N. Usmani and M. Tavakoli},
    booktitle={Intelligent Robots and Systems (IROS), 2015 IEEE/RSJ International Conference on},
    title={Extended bicycle model for needle steering in soft tissue},
    year={2015},
    pages={4375-4380},
    doi={10.1109/IROS.2015.7353998},
    month={Sept},}

    Abstract

    This paper represents an extension to the kinematic bicycle model for beveled-tip needle motion in soft tissue, which accounts for non-constant curvature paths for the needle tip. For a tissue that is not stiff relative to the needle, the tissue deformation caused by needle insertion deviates the needle tip position from a constant curvature path. The proposed model is obtained by replacing the bicycle wheels with omnidirectional wheels that move in two orthogonal directions independently. Such wheels can move sideways, providing a means for modeling the deviations of the needle tip from a constant curvature path by incorporating new parameters in the model. Using an experimental setup, the needle is inserted into soft phantom tissue at different constant velocities and model parameters are fitted to experimental data. The model is verified by comparing the results from the model to empirical data.

  24. T. Lehmann, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - A virtual sensor for needle deflection estimation during soft-tissue needle insertion. IEEE International Conference on Robotics and Automation (ICRA), Seattle, USA, May 2015. 10.1109/ICRA.2015.7139346 (pdf) BibTeX

    @INPROCEEDINGS{Lehmann2015b,
    author={T. Lehmann and C. Rossa and N. Usmani and R. Sloboda and M. Tavakoli},
    booktitle={2015 IEEE International Conference on Robotics and Automation (ICRA)},
    title={A virtual sensor for needle deflection estimation during soft-tissue needle insertion},
    year={2015},
    pages={1217-1222},
    doi={10.1109/ICRA.2015.7139346},
    ISSN={1050-4729},
    month={May},}

    Video

    Abstract

    A tissue-independent model to estimate needle deflection during insertion in soft tissue is presented in this paper. A force/torque sensor is connected to the needle base in order to measure forces and moments during insertion due to needle deflection. A static mechanical model, which is based on the Euler-Bernoulli beam equation and the balance of forces applied by the tissue onto the needle takes these force and moment measurements as input. The needle tip deflection can then be calculated based on the beam model undergoing these forces. Three different needle-tissue interaction models are presented. Their estimation performance is evaluated and experimentally compared by carrying out insertion experiments into phantom tissue. The experimental results show a precise estimate of needle tip deflection for a novel virtual sensor introduced in this work. The main advantage of this virtual sensor approach is that measurements obtained from the force/torque sensor are the only necessary model inputs. Furthermore, the approach does not rely on ultrasound or other image-based needle observation techniques. This makes the virtual sensor suitable for real-time feedback of needle tip deflection.

  25. M. Khadem, B. Fallahi, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - A mechanics-based model for simulation and control of flexibleneedle steering in soft tissue. IEEE International Conference on Robotics and Automation (ICRA), Seattle, USA, May 2015. 0.1109/ICRA.2015.7139499 (pdf) BibTeX

    @INPROCEEDINGS{Khadem2015c,
    author={M. Khadem and B. Fallahi and C. Rossa and R. S. Sloboda and N. Usmani and M. Tavakoli},
    booktitle={2015 IEEE International Conference on Robotics and Automation (ICRA)},
    title={A mechanics-based model for simulation and control of flexible needle insertion in soft tissue},
    year={2015},
    pages={2264-2269},
    doi={10.1109/ICRA.2015.7139499},
    ISSN={1050-4729},
    month={May},}

    Video

    Abstract

    In needle-based medical procedures, beveled-tip flexible needles are steered inside soft tissue with the aim of reaching pre-defined target locations. The efficiency of needle-based interventions depends on accurate control of the needle tip. This paper presents a comprehensive mechanics-based model for simulation of planar needle insertion in soft tissue. The proposed model for needle deflection is based on beam theory, works in real-time, and accepts the insertion velocity as an input that can later be used as a control command for needle steering. The model takes into account the effects of tissue deformation, needle-tissue friction, tissue cutting force, and needle bevel angle on needle deflection. Using a robot that inserts a flexible needle into a phantom tissue, various experiments are conducted to separately identify different subsets of the model parameters. The validity of the proposed model is verified by comparing the simulation results to the empirical data. The results demonstrate the accuracy of the proposed model in predicting the needle tip deflection for different insertion velocities.

  26. M. Waine, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - 3D shape visualization of curved needles in tissue from 2D ultrasound images using RANSAC. IEEE International Conference on Robotics and Automation (ICRA), Seattle, USA, May 2015. 10.1109/ICRA.2015.7139855 (pdf) BibTeX

    @INPROCEEDINGS{Waine2015c,
    author={M. Waine and C. Rossa and R. Sloboda and N. Usmani and M. Tavakoli},
    booktitle={2015 IEEE International Conference on Robotics and Automation (ICRA)},
    title={3D shape visualization of curved needles in tissue from 2D ultrasound images using RANSAC},
    year={2015},
    pages={4723-4728},
    doi={10.1109/ICRA.2015.7139855},
    ISSN={1050-4729},
    month={May},}

    Video

    Abstract

    This paper introduces an automatic method to visualize 3D needle shapes for reliable assessment of needle placement during needle insertion procedures. Based on partial observations of the needle within a small sample of 2D transverse ultrasound images, the 3D shape of the entire needle is reconstructed. An intensity thresholding technique is used to identify points representing possible needle locations within each 2D ultrasound image. Then, a Random Sample and Consensus (RANSAC) algorithm is used to filter out false positives and fit the remaining points to a polynomial model. To test this method, a set of 21 transverse ultrasound images of a brachytherapy needle embedded within a transparent tissue phantom are obtained and used to reconstruct the needle shape. Results are validated using camera images which capture the true needle shape. For this experimental data, obtaining at least three images from an insertion depth of 50 mm or greater allows the entire needle shape to be calculated with an average error of 0.5 mm with respect to the measured needle curve obtained from the camera image. Future work and application to robotics is also discussed.

  27. J. Carriere, C. Rossa, N. Usmani, R. Sloboda, and M. Tavakoli - Needle shape estimation in soft tissue based on partial ultrasound image observation. IEEE International Conference on Robotics and Automation (ICRA), Seattle, USA, May 2015. 10.1109/ICRA.2015.7139501 (pdf) BibTeX

    @INPROCEEDINGS{Carriere2015c,
    author={J. Carriere and C. Rossa and N. Usmani and R. Sloboda and M. Tavakoli},
    booktitle={2015 IEEE International Conference on Robotics and Automation (ICRA)},
    title={Needle shape estimation in soft tissue based on partial ultrasound image observation},
    year={2015},
    pages={2277-2282},
    doi={10.1109/ICRA.2015.7139501},
    ISSN={1050-4729},
    month={May},}

    Abstract

    We propose a method to estimate the entire shape of a long flexible needle, suitable for a needle insertion assistant robot. This method bases its prediction on only a small segment of a needle, imaged via ultrasound, after insertion. An algorithm is developed that can segment a needle observed partially in ultrasound images and fully in camera images, returning a polynomial representation of the needle shape after RANSAC processing. The polynomial corresponding to the partial needle observation in ultrasound images is used as the input to a needle-tissue interaction model that predicts the entire needle shape. The needle shape predicted by the model is compared to the segmented needle shape based on camera images to validate the proposed approach. The results show that the entire needle shape can be accurately predicted in tissues of varying stiffness based on observation of parts of the needle in an ultrasound image.

  28. C. Rossa, A. Anastassova, A. Micaelli, and J. Lozada - Perceptual evaluation of the passive/active torque and stiffness asymmetry of a hybrid haptic device. International Conference Eurohaptics 2014, LNCS 8618, pp. 55-60. Versailles, France, Jun 2014. 10.1007/978-3-662-44193-0_8 ( pdf) BibTeX

    @Inbook{Rossa2014e,
    author={Rossa, Carlos and Anastassova, Margarita and Micaelli, Alain and Lozada, Jos{\'e}},
    title={Perceptual Evaluation of the Passive/Active Torque and Stiffness Asymmetry of a Hybrid Haptic Device},
    bookTitle={Haptics: Neuroscience, Devices, Modeling, and Applications: 9th International Conference, EuroHaptics 2014, Versailles, France, June 24-26, 2014, Proceedings, Part I},
    year={2014},
    publisher={Springer Berlin Heidelberg},
    address={Berlin, Heidelberg},
    pages={55--60},
    isbn={978-3-662-44193-0},
    doi={10.1007/978-3-662-44193-0_8},
    url={http://dx.doi.org/10.1007/978-3-662-44193-0_8}}

    Abstract

    Hybrid haptic interfaces combining brakes and motors can present dissimilar torque and stiffness capabilities when dissipating or restoring energy. This paper aims at identifying the asymmetry thresholds that lead to an alteration in the perception of elasticity simulated by such devices. 17 subjects took part in an experiment consisting in interacting with virtual springs with either controllable stiffness or torque asymmetry levels, and identifying if the springs were symmetric or not. Experimental results indicate that when the decompression stiffness or torque were less than 80 % and 60 % of the compression stiffness or torque respectively, users did not perceive the asymmetry in 80 % of trials. This suggests that hybrid devices can present dissimilar active/passive torque or stiffness capabilities without affecting the perception of elasticity.

  29. C. Rossa, J. Lozada, and A. Micaelli - Actionneur hybride pour interface à retour d'effort. SEEDS/ JCGE. Saint Nazaire, France, Jun 2013. 10.13140/2.1.3502.0160 (pdf) BibTeX

    @INPROCEEDINGS{Rossa2013a,
    author={Rossa, Carlos and Micaelli, Alain and Lozada, Jos{\'e}},
    title={Actionneur hybride pour interface à retour d'effort},
    bookTitle={In SEEDS/ JCGE}
    year={2013},
    doi={10.1007/978-3-662-44193-0_8},}

    Abstract

    Cet article présente la conception et la commande d'un nouvel actionneur hybride pour interface à retour haptique. Le dispositif comprend un moteur à courant continu et deux freins magnéto-rhéologiques unidirectionnels. Chaque frein est associé à une roue libre afin de générer un couple de freinage dans une seule direction. De ce fait, lorsque le frein et le moteur sont activés en même temps pour imposer un couple de freinage, le couple fourni par le moteur n'est pas dissipé dans le frein. L'actionneur peut générer 5.5Nm, ce qui correspond à un couple par unité de volume de 17.75 kN/m 2 . Comparé à un moteur seul connecté à un réducteur de vitesse idéal, les résultats démontrent que l'actionneur hybride génère moins de frottement et présente moins d'inertie. Une nouvelle approche de commande basée sur le partage optimal d'impédance est proposée. Les gains d'asservissement sont ajustés en temps réel de manière à respecter la consigne et les critères de stabilité. Les lois de commande, indépendantes de l'environnement virtuel, permettent l'utilisation de l'actionneur dans une large gamme de dispositifs haptiques.

    The design and control of a 5.5Nm maximal torque, 17.75 kN/m 2 torque density hybrid actuator for haptic feedback devices are presented. The system employs two unidirectional magneto-rheological fluid based brakes and a DC motor. The brakes are coupled to opposite overrunning clutches. By these means, each brake can generate a torque only in a defined direction. Thus, when both a brake and a motor are engaged to constrain the motion of the end-effector, the torque provided by the motor is not dissipated in the brake. Theoretical results demonstrate that the system generates less friction and presents less inertia than a DC motor with an ideal capstan transmission system. The designed control laws determine an optimal shear of efforts between the brakes and the motor in terms of stiffness and energy of the virtual environment, in order to achieve high torque capability while maintaining stability and safety. The control laws do not necessitate a measure of interaction forces. Besides, the design of the actuator and the proposed control laws are completely independent of the virtual environment to allow the implementation of the system in many different haptic feedback devices

  30. C. Rossa, J. Lozada, and A. Micaelli - Stable haptic interaction using passive and active actuators. IEEE International Conference on Robotics and Automation (ICRA), pp. 2386, 2392. Karlsruhe, Germany, May 2013. 10.1109/ICRA.2013.6630901 ( pdf) BibTeX

    @INPROCEEDINGS{Rossa2013d,
    author={C. Rossa and J. Lozada and A. Micaelli},
    booktitle={Robotics and Automation (ICRA), 2013 IEEE International Conference on},
    title={Stable haptic interaction using passive and active actuators},
    year={2013},
    pages={2386-2392},
    doi={10.1109/ICRA.2013.6630901},
    ISSN={1050-4729},
    month={May},}

    Abstract

    This paper presents a stable control method for a hybrid haptic device comprising a brake and a motor. A review of stability condition via describing function analysis is first presented. The results show that while brakes are intrinsically stable, an active device is limited in terms of stiffness. The stability is however improved if the brake simulates a physical damping. Subsequently, the stability condition is obtained via passivity condition analysis. The results demonstrate that the stiffness is improved by engaging both actuators to create resistive forces and the passivity is respected assuming a passive virtual environment. An energy and a stiffness-bounding algorithms have been developed in order to assure the stability of the coupled system in this case. It has been tested and validated using a 1-DOF hybrid haptic device by the simulation of an unstable and an active virtual environments respectively . Experimental results show that the displayable stiffness is improved under stability conditions using the control method. Furthermore, it allows the hybrid system to simulate nonlinear and unstable virtual environments and the controller remains independent of the virtual environment model.

  31. C. Rossa, J. Lozada, and A. Micaelli - A new hybrid actuator approach for force-feedback devices. IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pp. 4054-4049. Vila Moura, Portugal, Oct 2012. 10.1109/IROS.2012.6385784 ( pdf) BibTeX

    @INPROCEEDINGS{Rossa2012a,
    author={C. Rossa and J. Lozada and A. Micaelli},
    booktitle={2012 IEEE/RSJ International Conference on Intelligent Robots and Systems},
    title={A new hybrid actuator approach for force-feedback devices},
    year={2012},
    pages={4054-4059},
    doi={10.1109/IROS.2012.6385784},
    ISSN={2153-0858},
    month={Oct},}

    Abstract

    A new concept of hybrid actuator for haptic devices is proposed. This system combines a controllable magnetorheological brake with a conventional DC motor. Both actuators are linked through an overrunning clutch. Thus, the motor is connected to the handle while the brake can exert a resistive force only in a defined direction. This configuration enables the brake and the motor to be engaged at the same time because the torque imposed by the motor is not canceled by the brake. The concept and its control laws have been investigated using a 1-DOF haptic device. The experimental results show that is possible to combine a powerful brake with a small DC motor. This approach reduces the power consumption, expand the range of forces, achieve global stability in the system providing thereby safety to the user. Besides, the proposed independent control laws enable the actuator to be adaptable in many different haptic applications.

  32. C. Rossa, J. Lozada, and A. Micaelli - Magnetic flux analysis on magnetorheological actuators can detect external force variation. IEEE Sensors Conference. Taipei, Taiwan, Oct 2012. 10.1109/ICSENS.2012.6411116 ( pdf) BibTeX

    @INPROCEEDINGS{Rossa2012b,
    author={C. Rossa and J. Lozada and A. Micaelli},
    booktitle={Sensors, 2012 IEEE},
    title={Magnetic flux analysis on magnetorheological actuators can detect external force variation},
    year={2012},
    pages={1-4},
    doi={10.1109/ICSENS.2012.6411116},
    ISSN={1930-0395},
    month={Oct},}

    Abstract

    Magnetorheological (MR) fluids consist of a suspension of ferromagnetic micron-sized particles dispersed in a carrier fluid. A magnetic field induces the magnetization of the particles which then form chain-like structures aligned in the direction of the field. The structures interact with the magnetic poles, as a consequence, the relative displacement of the poles due to the action of an external force, inclines the particle chains and alters the magnetic environment. This phenomenon can be perceived as a magnetic reluctance variation on the fluid gap. The paper focuses on a MR-based brake equipped with a magnetic flux variation measurement system, which is able to detect when the chain-like structures begin to rupture. Based on the same principle, the system is also capable of detecting a change in the direction of an external force.

  33. C. Rossa, J. Lozada, and A. Micaelli - Interaction power flow based control of a 1-DOF hybrid haptic device. International Conference Eurohaptics 2012, pp. 151-156. Tampere, Finland, Jun 2012. 10.1007/978-3-642-31404-9_26 ( pdf)
    BibTeX

    @Inbook{Rossa2012q,
    author={Rossa, Carlos and Lozada, Jos{\'e} and Micaelli, Alain},
    title={Interaction Power Flow Based Control of a 1-DOF Hybrid Haptic Interface},
    bookTitle={Haptics: Perception, Devices, Mobility, and Communication: International Conference, EuroHaptics 2012, Tampere, Finland, June 13-15, 2012 Proceedings, Part II},
    year={2012},
    publisher={Springer Berlin Heidelberg},
    address={Berlin, Heidelberg},
    pages={151--156},
    isbn={978-3-642-31404-9},
    doi={10.1007/978-3-642-31404-9_26},
    url={http://dx.doi.org/10.1007/978-3-642-31404-9_26},}

    Abstract

    A control method based on instantaneous interaction energy is used to control a hybrid haptic actuator, comprising magnetorheological brake and a DC motor, linked in parallel. We have combined this method with a quantitative analysis of interaction forces to develop two control variants, which can determine an optimal sharing of efforts between the active and dissipative actuators and make the system more reactive. The proposed control laws have been validated in a rotary 1-DOF force-feedback device.

Theses | Thèses
  1. Olivia Wilz - Robotic and haptic assistance for kidney access during percutaneous nephrolithotomy, Masters of Applied Science in Mechanical Engineering, Ontario Tech University, Aug 2021. (pdf) BibTeX

    @phdthesis{Wilz_thesis,
    title={Robotic and haptic assistance for kidney access during percutaneous nephrolithotomy},
    author={Olivia, Wilz},
    year={2021},
    school={Ontario Tech University}, }

    Abstract

    Percutaneous nephrolithotomy (PCNL) is a procedure to remove kidney stones through an incision in the patient’s back. Gaining kidney access is the most challenging task in this procedure and the cause of many complications. This thesis presents semi-autonomous solutions for improving PCNL procedure outcomes. First, a cyber-physical PCNL simulator incorporating haptic feedback and simplifying surgeon mental workload via teleoperation of a nephroscope, the surgeon controls the tooltip position while a robotic agent controls its orientation. This thesis then explores how subtask automation can further improve the procedure. A multi-objective path planning algorithm is implemented to generate multiple suitable paths for kidney access, from which an expert surgeon selects one for execution. The robotic agent then steers the tool along the path autonomously. A further advancement adds a tool/tissue interaction model which determines tool bending; thereby providing accurate trajectory tracking. The concepts are validated experimentally in ex-vivo and phantom tissues.

  2. Rick Tan - Electrical Impedance Tomography for Internal Radiation Therapy, Masters of Applied Science in Mechanical Engineering, Ontario Tech University, Aug 2021. (pdf) BibTeX

    @phdthesis{Tan_thesis,
    title={Electrical impedance tomography for internal radiation therapy},
    author={Rick, Tan},
    year={2021},
    school={Ontario Tech University}, }

    Abstract

    Internal radiation therapy is a radiation-based treatment for various forms of localized cancer. In this treatment, several needles or catheters are inserted percutaneously into the tissue, and radiation is delivered through them directly to the site of the tumour growth. Imaging methods to delineate the dominant tumour are imperative to ensure the maximum success of the radiation procedure. This thesis investigates a new imaging approach for internal radiation therapy based on the principle of electrical impedance tomography (EIT). A novel procedure utilizing brachytherapy needles as electrodes is proposed to map the internal electrical conductivity of the tissue. Since cancerous tissue exhibits different levels of conductivity than healthy tissue, it is hypothesized that the electrical conductivity map of the tissue can be used to delineate cancerous nodules via EIT. In addition, this thesis explores the use of electrical impedance modulation via ultrasound to improve the spatial resolution of EIT images.

  3. Brayden Kent - Tissue classification from electric impedance spectroscopy for haptic feedback in minimally invasive surgery, Masters of Applied Science in Mechanical Engineering, Ontario Tech University, Oct 2020. (pdf) BibTeX

    @phdthesis{Kent_thesis,
    title={Tissue classification from electric impedance spectroscopy for haptic feedback in minimally invasive surgery},
    author={Kent, Brayden},
    year={2020},
    school={Ontario Tech University}, }

    Abstract

    The lack of haptic feedback in the currently available teleoperated surgical robots creates a sensory disconnect from the surgeon and their patient. Attempts to remedy this through force sensors pose additional challenges that are not easily solved. This thesis presents processes to use the electric impedance instead of the mechanical impedance of tissues to develop haptic feedback for surgical robots. Electric impedance spectroscopy (EIS) is a method used to measure the dielectric properties of tissues. Fueled by a desire to identify tissues at the tip of the tools used in minimally invasive procedures, such as brachytherapy and stereostatic surgery, a modified surgical needle was created that acts as an EIS probe. The new tool can successfully measure the electric impedance for a variety of tissues: gel-based phantoms, ex-vivo tissue, and freshly excised organs. Processes for fitting the electric impedance of these tissues to the double dispersion Cole model were developed including approaches using Newton-Raphson and a multi-objective genetic algorithm. It is shown using least square error, k-Nearest Neighbour and Naïve Bayes that the tissue can be classified using the measured electric impedance and the extracted model parameter values. The thesis culminates in applications of using EIS as part of implementing vibrotactile feedback and force feedback in teleoperated minimally invasive surgery. The applications involved sets of user trials to validate its effectiveness in identifying the tissue through haptic feedback.

  4. Maciej Lacki - Analysis, development, and control of mlti-degree-of-freedom passive haptic devices, Masters of Applied Science in Mechanical Engineering, Ontario Tech University, Aug 2020. Winner of the 2021 Ontario Tech Outstanding Thesis Award. (pdf) BibTeX

    @phdthesis{Lacki_thesis,
    title={Analysis, Development, and Control of Multi-Degree-of-Freedom Passive Haptic Devices},
    author={Lacki, Maciej},
    year={2020},
    school={Ontario Tech University}, }

    Abstract

    Stability and transparency are key design requirements in haptic devices. Replacing conventional electric motors with passive actuators such as brakes or dampers can improve both stability and transparency as passive actuators can display a wide range of impedance while guaranteeing stability. However, passive haptic devices suffer from a serious drawback; their force output is difficult to control. This issue was addressed extensively for planar manipulators but devices with higher degrees-of-freedom (DOF) have not been examined. This thesis proposes a generalized framework for analyzing and controlling higher-DOF devices and examining the effects of the kinematic structure on the force output capability. A first of its kind 3-Degree-of-Freedom (DOF) parallel passive haptic device was developed along with a novel controller designed specifically for the 3-DOF passive device. This thesis also investigates the use of a nonlinear disturbance observer to aid in the control of passive haptic devices.

  5. Brayden DeBoon - Multimodal Series Elastic Actuator for Human-Machine Interaction with Applications in Robot-Aided Rehabilitation. Ontario Tech University, Masters of Applied Science in Mechanical Engineering, Ontario Tech University, Dec 2019. (full text), (pdf) BibTeX

    @phdthesis{DeBoon_theesis,
    title={Multimodal series elastic actuator for human-machine interaction with applications in robot-aided rehabilitation},
    author={DeBoon, Brayden},
    year={2019},
    school={Ontario Tech University}, }

    Abstract

    Series elastic actuators (SEAs) are becoming an elemental building block in collaborative robotic systems. They introduce an elastic element between the mechanical drive and the end-effector, making otherwise rigid structures compliant when in contact with humans. Topologically, SEAs are more amenable to accurate force control than classical actuation techniques, as the elastic element may be used to provide a direct force estimate. The compliant nature of SEAs provides the potential to be applied in robot-aided rehabilitation. This thesis proposes the design of a novel SEA to be used in robot-aided musculoskeletal rehabilitation. An active disturbance rejection controller is derived and experimentally validated and multiobjective optimization is executed to tune the controller for best performance in human-machine interaction. This thesis also evaluates the constrained workspaces for individuals experiencing upper-limb musculoskeletal disorders. This evaluation can be used as a tool to determine the kinematic structure of devices centred around the novel SEA.

  6. C. Rossa - Conception et commande d'un actionneur hybride pour les interfaces homme-machine. Université Pierre et Marie Curie, PhD thesis, Dec 2013. (theses.fr) (slides) (full text) BibTeX

    @phdthesis{rossa2013hybrid,
    title={A hybrid actuation system for haptic interfaces},
    author={Rossa, Carlos},
    year={2013},
    school={Univeristé Pierre et Marie Curie - Paris 6}, }

    Abstract

    Cette thèse aborde la conception et la commande d'un nouveau système d'actionnement pour interface à retour haptique. Nous proposons un dispositif hybride comprenant un moteur à courant continu et deux freins magnétorhéologiques. Chaque frein étant associé à une roue libre, son couple de freinage ne peut être transmis que dans une seule direction. De ce fait, lorsqu'un frein et le moteur sont activés en même temps, le frein ne bloque pas le moteur, ce qui permet de combiner les avantages de chaque d'actionneur et d'améliorer la qualité du rendu haptique. L'actionneur peut générer 5. 5Nm, avec un couple par unité de volume de 17. 75kN/m2. Les résultats démontrent que l'actionneur hybride présente moins de frottement et moins d'inertie comparé à un moteur électrique seul connecté à un réducteur de vitesse idéal. Une nouvelle approche de commande basée sur le partage d'impédance est proposée. Les gains d'asservissement relatifs à la raideur simulée par chaque actionneur sont ajoutés en temps réel de manière à respecter les consignes et les critères de stabilité. Ces lois de commandes sont indépendantes de l'environnement virtuel et permettent l'utilisation de l'actionneur dans une large gamme de dispositifs à retour de forces.

    The design and control of a 5. 5Nm maximal torque, 17. 75kN/m2 torque density hybrid actuator for haptic feedback devices are presented. The system employs two unidirectional magneto-rheological fluid based brakes and a DC motor. The brakes are coupled to opposite overrunning clutches. By these means, each brake can generate a torque only in a defined direction. Thus, when both a brake and a motor are engaged to constrain the motion of the end-effector, the brake does not block the motor. Theoretical results demonstrate that the system generates less friction and presents less inertia compared to a DC motor associated to an ideal capstan transmission. The proposed control laws determine the shear of efforts between the brakes and the motor in terms of stiffness and energy of the virtual environment, in order to achieve high torque capability while maintaining stability and safety. The control laws do not necessitate a measure of interaction forces. Besides, the design of the actuator and the control laws are completely independent of the virtual environment allowing for the implementation of the system in many different haptic feedback devices.

Book chapters | Chapitres d'ouvrages scientifiques
  1. M. Lacki, and C. Rossa - Towards the Ideal Haptic Device: Review of Actuation Techniques for Human-Machine Interfaces - Human-robot interaction: control, analysis, and design. 2020, in press.
  2. C. Rossa, M. Keri, and M. Tavakoli - Brachytherapy needle steering guidance using image overlay - Handbook of Research on Biomimetics and Biomedical Robotics. 2018. 10.4018/978-1-5225-2993-4 ( pdf) BibTeX

    @inbook{Rossa2018chapter,
    author={C. Rossa and M. Keri and M. Tavakoli},
    booktitle={Handbook of Research on Biomimetics and Biomedical Robotics},
    title={Brachytherapy needle steering guidance using image overlay},
    year={2018},
    pages={191-204},
    doi={10.4018/978-1-5225-2993-4.ch008},
    }

    Abstract

    This chapter presents a physical simulator for needle steering in brachytherapy. As the user inserts the needle in a phantom tissue, images of the needle and prostate shape reconstructed from 2D transverse ultrasound images are displayed online in a semi-transparent mirror. During insertion, the user sees the images as if they were floating inside the phantom accounting for scale and orientation. The ultrasound images of the needle are combined with a needle-tissue interaction model that predicts the needle deflection further along the insertion process. The necessary manoeuvres that bring the needle towards its intended target location are displayed to the user along with the actual needle location. This platform allows the user to test different manual and robotic-assisted needle steering techniques. Reported experimental results confirm the accuracy of the system in reconstructing and overlaying images onto the phantom.

Patents | Brevets
  1. C. Rossa, R. Sloboda, N. Usmani, and M. Tavakoli - Hand-held device and computer-implemented system and method for assisted steering of a percutaneously inserted needle. Dispositif à main et système mis en oeuvre par ordinateur et méthode de direction assistée d'une aiguille inserée de manière percutaneé, 2017. CA2967482 (A1), CIPO, (pdf) BibTex

    @misc{Rossa2017_patent,
    title={Hand-held device and computer-implemented system and method for assisted steering of a percutaneously inserted needle},
    author={Rossa, Carlos and Usmani, Nawid and Sloboda, Ron and Tavakoli, Mahdi},
    year={2017},
    month=May,
    note={CA2967482 (A1)}
    }

    Abstract

    A hand-held device for assisted steering of a percutaneously inserted needle comprises a handle, an actuation unit, and a haptic feedback unit. A computer-implemented system calculates a needle shape and position based on one or a combination of analysis of ultrasound images and determination of needle insertion parameters based on electronic signals generated by a sensor unit. The system calculates a correction to a needle insertion parameter to achieve a target needle trajectory, including a correction to a needle axial rotation. The system activates the actuation unit to rotate the needle in accordance with the correction to the needle axial rotation, and activates to the haptic feedback unit to vibrate the handle in a vibration pattern determined by a rules database depending on one or a combination of the calculated needle shape, the calculated needle position, and the correction to the needle insertion parameter.

  2. C. Rossa, J. Lozada, and A. Micaelli - Actuator with hybrid actuation for a force feedback interface. WO2013189946, US20150301553 (A1), Jun 2013. (Wipo) ( FPO) ( pdf WO) ( pdf US) BibTex

    @misc{rossa2015actuator,
    title={Actuator with hybrid actuation for a force feedback interface},
    author={Rossa, Carlos and Lozada, Jos{\'e} and Micaelli, Alain},
    year={2015},
    month=oct,
    note={US Patent 20,150,301,553}
    }

    Abstract

    Actionneur pour interface à retour de forces comportant un arbre solidaire en rotation d'un organe d'interaction de ladite interface, un moteur électrique entraînant en rotation l'arbre (3) dans un sens horaire et dans un sens antihoraire, un premier dispositif à roue libre (4) monté sur l'arbre (3) et un premier système de freinage (8) apte à freiner la rotation de l'arbre (3) par l'intermédiaire du dispositif à roue libre (8), un deuxième dispositif à roue libre (6) monté sur l'arbre (3) en opposition par rapport au premier dispositif à roue libre (4), un deuxième système de freinage (10) apte à freiner la rotation de l'arbre (3) par l'intermédiaire du deuxième dispositif à roue libre (6) dans un sens opposé à celui du premier système de freinage (8). Le moteur pouvant appliquer un effort actif à l'arbre (3) dans le sens opposé à celui de la force de freinage.

    An actuator for a force feedback interface comprising a shaft constrained to rotate with an interacting member of said interface, an electric motor rotating the shaft (3) in a clockwise direction and in an anti-clockwise direction, a first free-wheel device (4) mounted on the shaft (3) and a first braking system (8) capable of braking the rotation of the shaft (3) via the free-wheel device (8), a second free-wheel device (6) mounted on the shaft (3) opposite the first free-wheel device (4), a second braking system (10) capable of braking the rotation of the shaft (3) via the second free-wheel device (6) in a direction opposite that of the first braking system (8). The motor can apply an active load to the shaft (3) in the opposite direction to that of the braking force.

Technical Reports | Rapports Techniques
  1. V. Samy - Développement d'une interface hybride à retour de force à 2 degrés de liberté. Rapport de projet de fin d'études - Institut National des Sciences Appliquées (INSA) de Lyon, et Commissariat à l'Energie Atomique (CEA), Sep 2013. (pdf)
  2. A. Jaegy - Conception d'un actionneur hybride frein/moteur pour les interfaces haptiques. Rapport de projet de fin d'études - Institut National des Sciences Appliquées (INSA) de Strasbourg, et Commissariat à l'Energie Atomique (CEA), Aug 2012. (pdf)
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