Singularity analysis of a class of composite serial in-parallel robots

This paper presents the singularity analysis of a family of 14 composite serial in-parallel six degree-of-freedom robots, having a common parallel submechanism. The singular configurations of this class of robots are obtained by applying line geometry methods to a single, augmented Jacobian matrix whose rows are Plucker coordinates of the lines governing the submechanism motion. It is shown that this family of robots possesses three general parallel singularities that are attributed to the general complex singularity. The results were verified experimentally on a prototype of a composite serial in-parallel robot that was synthesized and constructed for use in medical applications.