Master/slave control of flexible instruments for minimally invasive surgery

Stras is a flexible robotic system based on the Anubis^® platform from Karl Storz and is aimed for intralu-minal and transluminal procedures. It is composed of three cable-driven sub-systems, one endoscope and two insertable instruments. The bending instruments have three degrees of freedom and can be teleoperated by the user via two commercial master interfaces (Omega.7, Force Dimension). In this paper we investigate several ways to map the motions from the master side to the instruments, from joint per joint control to cartesian control. We describe these mappings and compare them in elementary tasks in an attempt to analyze how non-linearities affect the accuracy of control. Results show that joint control and pseudo-cartesian control provide equivalent accuracy but with different difficulties for the user.