Topology of serial and parallel manipulators and topological diagrams

This paper deals with manipulator topology. The term topology was first introduced into robotics to characterize the kinematic structure of a manipulator without reference to its dimensions. Its dimension-independent aspect does not pose a considerable problem to planar manipulators, but makes it no longer appropriate to describe spatial manipulators especially spatial parallel manipulators, because such important properties as the degree of freedom of a manipulator and the degree of mobility of its end-effector as well as the nature of the mobility are highly dependent on some dimensional elements. In order to address this fundamental issue in kinematic synthesis, we introduced essential constraints into the concept of topology through the analysis of representative architectures, proposed a topological representation which provides a better correspondence between the representation and the intended manipulators, a necessity for topological synthesis and documentation. Introducing the essential constraints can also improve the efficiency of some synthesis methods.