Kinematics and synthesis of a type of mechanisms with multiple remote centers of motion

Abstract

Remote center of motion (RCM) mechanism, widely used as a wrist of minimally invasive surgery robot, is a kind of minor-mobility mechanism with part of it rotating around a fixed point distal from it. However, there is no physical revolute joint at that point. In this paper, kinematics of mechanisms with two remote centers of motion or multiple remote centers of motion (multi-RCM) are researched. The relationship between geometrics and kinetic characteristics of RCM mechanisms is found. Mechanisms with multi-loop kinematic chain are developed and are used to synthesize multiple RCM mechanisms. This type of dimension synthesis method proposed to design multi-RCM mechanisms just needs the initial condition of fixed positions of the frame and remote centers. A synthesis example and a potential application are presented. The synthesis method of multi-RCM mechanisms is effective in constructing new type of mechanisms.