Haptic interface for virtual reality based minimally invasive surgery simulation

This paper deals with the mechanical design and control of a novel 4-DOF force-reflecting manual man-machine interface for virtual reality based minimally invasive surgery simulation for training purposes. The realized force feedback manipulator is based on a novel spherical remote-center-of-motion mechanical structure, and features compactness, high sustained output force capability, low friction, zero backlash, and a particularly large, singularity-free workspace. An implicit force control scheme is employed for virtual object impedance simulations. Active compensation of manipulator gravity and actuator friction allows one to simulate static and dynamic object attributes including weight, elasticity, and viscosity over a wide dynamic range of approximately 1:100. Finally, a novel 'supervisory control' concept is proposed which allows one to connect the haptic feedback system to the corresponding graphical simulation environment with highly differing bandwidth requirements.