The Equivalent Mechanical Model of Topological Graphs and the Isomorphism Identification of Kinematic Chains

Abstract

In type synthesis of mechanisms, isomorphic identification of kinematic chains is a key issue, which has been studied for many years. In this paper, a new topological invariant, a character array of edge is constructed based on a novel model called an equivalent mechanical model. This invariant is used as a necessary condition for recognizing the edges of two topological graphs. On this basis, a method of constructing mapping by closed loop is proposed. The constructed mapping is used as the adequacy of identification so as to accurately identify the isomorphism of two graphs. This method is sufficient and necessary, which has been successfully tested in the 10-vertex, 12-vertex, 15-vertex, 28-vertex topological graphs. This method is limited to planar mechanisms that consist of revolute joints.