A Geometrical Characterization of Workspace Singularities in 3R Manipulators

In this paper we present an algorithm, based on a level set representation of a crosssection of the Cartesian workspace of 3R regional manipulators, which is useful to show clearly the nature of the cusps and double points on the boundary. Furthermore it is shown that singularities of the level set surface (graph of the level set) characterize non-generic manipulators and we demonstrate the non-singular posture change ability of cuspidal manipulators with help of the level set surface.