Expanded spatial four-link motion and path generation with order and branch defect elimination

Abstract

This work addresses the inverse problems of expanded motion and path generation for the spatial (revolute–revolute–spherical–spherical, RRSS) linkage and the 4R spherical linkage with order and branch elimination. Two constrained non-linear equation systems are presented in this work for RRSS and 4R spherical motion and path generation with order and branching constraints. Both equation systems include the spatial four-link displacement model (by Suh and Radcliffe) as an objective function along with order and branching inequality constraints. As examples, both a branch defect-free and order defect-free RRSS linkage 4R spherical linkage are synthesized to approximate expanded groups of precision positions.