Type Synthesis of a 3DOF Wrist Applying the Coupled-Input Cable-Driven Parallel Robot

Abstract

The spatial cable-driven parallel robots (CDPRs) with low DOF (degree-of-freedom; n < 6) are like the physiological structure of bone and muscles, which are suitable for designing humanoid joints. Therefore, the type synthesis of the CDPR is of great interest for the design of new humanoid wrist joints. In this paper, we present a type synthesis of the coupled-input CDPRs to design a 3DOF wrist. Coupled input means that one actuator controls more than one cable. First, the Yamanouchi symbols of the coupled-input CDPRs are listed using the permutation group. In addition, two winding methods for the cable and the actuator are defined in the coupled-input CDPRs. Finally, a topology configuration of the coupled-input CDPR suitable for the 3DOF wrist model is determined based on a comparative analysis of the workspaces of a class of coupled-input CDPRs. It is shown that type synthesis of the coupled-input CDPRs is an effective way to innovate low DOF CDPRs.