4 research outputs found

    a teleoperation system for micro invasive brain surgery

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    AbstractThis paper deals with controller design issues for a neurosurgical teleoperator system. The specific application of interest consists of remotely inserting a linear-stage rigid endoscope into the patient's brain for microinvasive neurosurgery interventions. This work aims at evaluating advantages and drawbacks of using a general-purpose control architecture versus a simpler task-oriented architecture, from a point of view of stability and transparency. Experiments revealed that in spite of its simplicity, the task-oriented design allows an improvement in the trade-off between performance, transparency and stability requirements

    The Shape of Damping: Optimizing Damping Coefficients to Improve Transparency on Bilateral Telemanipulation

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    This thesis presents a novel optimization-based passivity control algorithm for hapticenabled bilateral teleoperation systems involving multiple degrees of freedom. In particular, in the context of energy-bounding control, the contribution focuses on the implementation of a passivity layer for an existing time-domain scheme, ensuring optimal transparency of the interaction along subsets of the environment space which are preponderant for the given task, while preserving the energy bounds required for passivity. The involved optimization problem is convex and amenable to real-time implementation. The effectiveness of the proposed design is validated via an experiment performed on a virtual teleoperated environment. The interplay between transparency and stability is a critical aspect in haptic-enabled bilateral teleoperation control. While it is important to present the user with the true impedance of the environment, destabilizing factors such as time delays, stiff environments, and a relaxed grasp on the master device may compromise the stability and safety of the system. Passivity has been exploited as one of the the main tools for providing sufficient conditions for stable teleoperation in several controller design approaches, such as the scattering algorithm, timedomain passivity control, energy bounding algorithm, and passive set position modulation. In this work it is presented an innovative energy-based approach, which builds upon existing time-domain passivity controllers, improving and extending their effectiveness and functionality. The set of damping coefficients are prioritized in each degree of freedom, the resulting transparency presents a realistic force feedback in comparison to the other directions. Thus, the prioritization takes effect using a quadratic programming algorithm to find the optimal values for the damping. Finally, the energy tanks approach on passivity control is a solution used to ensure stability in a system for robotics bilateral manipulation. The bilateral telemanipulation must maintain the principle of passivity in all moments to preserve the system\u2019s stability. This work presents a brief introduction to haptic devices as a master component on the telemanipulation chain; the end effector in the slave side is a representation of an interactive object within an environment having a force sensor as feedback signal. The whole interface is designed into a cross-platform framework named ROS, where the user interacts with the system. Experimental results are presented

    Control design issues for a microinvasive neurosurgery teleoperator system

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    This paper deals with controller design issues for a neurosurgical teleoperator system. The specific application of interest consists in remotely inserting a linear-stage rigid endoscope into the patient's brain for microinvasive neurosurgery interventions. This work aims at evaluating the applicability of an existing general-purpose control architecture, addressing its advantages and drawbacks with respect to a simple task-oriented architecture, specifically designed for the target application. Preliminary experiments revealed that the task-oriented design can better fit the application requirements
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