Kinematics of Robot Fingers with Circular Rolling Contact Joints

This paper examines the kinematics of robot fingers that use RR subassemblies coupled by rolling contact to provide versatile one degree‐of‐freedom mechanical joints. A three degree‐of‐freedom robot finger constructed with these joints is a 6R planar chain with the R‐joints coupled together in pairs. The focus is on coupling based on pure rolling of circular cylinders which can be realized by friction contact, gearing, or cable tendons. We derive the forward, inverse and rate kinematics for this 3(RR) open chain. We then focus on the two degree‐of‐freedom 2(RR) case to illustrate the geometry of the system. An example design of a robot finger that incorporates these joints in order to provide compact movement is provided. © 2003 Wiley Periodicals, Inc.