Etienne Dombre

Purpose Design a compact, ergonomic, and safe endoscope positioner dedicated to the sino-nasal tract, and the anterior and middle-stage skull base. Methods A motion and force analysis of the surgeon’s movement was performed on cadaver heads to gather objective data for specification purposes. An experimental comparative study was then performed with three different kinematics, again on cadaver heads, in order to define the best architecture satisfying the motion and force requirements. Results We quantified the maximal forces applied on the endoscope when traversing the sino-nasal tract in order to evaluate the forces that the robot should be able to overcome. We also quantified the minimal forces that should not be exceeded in order to avoid damaging vital structures. We showed that the entrance point of the endoscope into the nostril could not be considered, as in laparoscopic surgery, as a fixed point but rather as a fixed region whose location and dimensions depend on the targeted sinus. Conclusion From the safety and ergonomic points of view, the best solution would be a co-manipulated standard 6-degree of freedom robot to which is attached a gimbal-like passive remote manipulator holding the endoscope.

Ultrasound image-guided interventions are widespread in surgery because of the non-invasive character of the procedures. However, hand/eye synchronization is relatively difficult for a surgeon. Ultrasound image-based visual servoing is one way to perform this kind of surgery. In this work, the control of instrument motion based on ultrasound images through nonlinear model predictive control is investigated. This new scheme ensures the convergence of the instrument to the desired position and also offers the possibility of satisfying constraints such as joint limits, actuator saturation and visibility preserving. This paper describes the proposed controller. The efficiency and the robustness of the proposed solution to control a six degree-of-freedom mechanical system is first illustrated by simulation. Experiments on a Mitsubishi PA10 robot highlight the efficiency of the vision control scheme to handle constraints of ultrasound image-based visual servoing.

This paper presents a new pneumatically driven underactuated hand with two fingers and 3 phalanxes per finger. Two evidences have led the design of this hand. Firstly, the use of pneumatic energy facilitates the underactuation of the hand, indeed a single T-connector suffices to share out one input among two outputs. Secondly, non-backdrivable mechanisms have to be used in the transmission of phalanx's motion so that the hand is capable of producing form-closed grasps. This latter design principle is justified using a newly developed method that permits to study the form-closure property of a grasp exerted by an underactuated hand. Moreover, the intriguing ejection phenomenon is avoided thanks to non-backdrivable mechanisms that prohibit any backward motion of phalanxes when correctly positioned. An original mechanism called the "pneumatic parallelogram" is described, it enables the hand to perform fine pinch grasps. Finally, the optimal design of both fingers is addressed with respect to the force-isotropy of the finger and the positiveness of phalanx forces

This paper discusses the design of a control system for robotic-assisted surgery with haptic feedback. The operational space control has a position-position teleopearation architecture with the phantom in the loop, enabling telepresence in free-space and contact. The null space control guarantees that surgical kinematic constraints are fulfilled. Both task and posture control run active observers (AOBs) in Cartesian domain, taking into account force, velocity and position signals. Experiments with a D2M2 (direct drive medical manipulator) robot are presented