On the Topological Representation and Compatibility of Variable Topology Mechanisms

Abstract

Variable topology mechanisms can serve many design functions with only one mechanism through changing their topology, these mechanisms have raised broad interest and attracted many studies in recent years, yet few have consolidated the different types of these mechanisms, nor discussed them in the light of the space they operate in. This work classified the variable topology mechanisms, and presented an expression of the mechanism’s working space. Variable topology mechanisms are classified into three types, topology changed by intrinsic constraints, topology changed by joint geometry change, and topology changed by external constraints. The causes and effects of various constraints inducing a topology change are described with the operating space, compatibility characteristics of joints, loops, and working stages with the operating space are established, verifying whether joints will constraint and lock up each other. The admissible operating space for a loop interface pairs so that loops are compatible, and the requisites of different working stages being workable with each other are identified. As a result, some basic requirements for admissible variable topology mechanisms are unveiled, laying a foundation stone for systematical synthesis of variable topology mechanisms.