Vision assisted control for manipulation using virtual fixtures: experiments at macro and micro scales

We present the design and implementation of a vision-based system for micron-scale, cooperative manipulation of a surgical tool. The system is based on a control algorithm that implements a broad class of guidance modes called virtual fixtures. A virtual fixture, like a real fixture, limits the motion of a tool to a prescribed class or range. The implemented system uses vision as a sensor for providing a reference trajectory, and the control algorithm then provides haptic feedback involving direct, shared manipulation of a surgical tool. We have tested this system on the JHU Steady Hand robot and provide experimental results for path following and positioning on structures at both macroscopic and microscopic scales.