Virtual Rolling Contact Joint with Compliant Property

Abstract

This thesis proposes the mechanical design of a virtual rolling contact joint that has compliance properties. As popularly used joint, which are flexible joint and rolling contact joint, have advantages of mechanical uses, and disadvantage properties. With these two different joints, the tensegrity theory can combines joints into one mechanism of joint, which gets the properties of three different mechanisms into one joint. So, the proposed mechanism has one degree of freedom, compliance properties, and lightweight for size of mechanism.

Every structure of the proposed mechanism is based on the tensegrity structure, which only consists of elastic strings and rigid bodies. Also, it is compliance since it consists of only tensile parts and comprehensive parts. The structure is composed of three layers and has a similar range of motion and the motion of the joint. Based on the characteristics of the tensegrity, all the bodies are not in contact with each other and have the characteristics of flexible joints.

With that combination of different joints and mechanisms, it gets similar features with the human wrist. The wrist has three layers of structure which are distal radius ulna, radio-carpal bones, and mid-carpal bones. It has two degrees of freedom that works as a biaxial universal joint, which are flexion-extension(F/E) and adduction abduction(A/A). Although, the movement of F/E is more used for the A/A, and it moves as if the rolling contact joints are restricted to a certain degree.