Clearance and manufacturing errors' effects on the accuracy of the 3-RCC Spherical Parallel Manipulator

Abstract

This paper deals with the analysis of a spherical parallel manipulator (3RCC) to determine the error on the pose of the end effector as a function of the manufacturing errors of the different links and the presence of a clearance in the joints. The obtained model allowed us to identify the error on the platform in three cases, i.e., only manufacturing errors were considered, then only clearance in the joints was considered and finally the case of both sources of error were present in the system. It was shown, in particular, that the axial displacement in the C joints is quite important. The second result is the fact that the superposition principle does not work when we consider both the manufacturing errors and the clearance despite the assumption of small displacements.