Design and Prototyping of a Force-Reflecting Hand-Controller for Ultrasound Imaging

Abstract

This paper presents detailed design, analysis, prototyping, and testing of a novel force-reflecting hand-controller allowing physicians to control a robotic wrist and perform ultrasound examinations on patients in remote locations. The proposed device is a four degree-of-freedom mechanism with a fixed center-of-motion and uses symmetric parallel mechanisms. All movements of the device are kinematically decoupled, i.e., the hand-controller has independent drive systems for each standard ultrasound motion. A technique has been adapted to statically balance the weight of the device over its entire workspace using a single tension spring. The prototype of the device has been constructed and evaluated for ultrasound imaging of kidney and spleen. Maximum and accuracy of the output force are analytically determined and performance of the device in terms of static balancing, static-friction break-away force, and maximum achievable impedances are experimentally evaluated.