A New Method for Motion-Decoupling Identification of Parallel Mechanisms

Abstract Motion-decoupling identification (MDI) for parallel mechanism (PM) is a significant issue in the analysis and design of PMs. In general, people use the Jacobian matrix method to determine whether a given PM has motion-decoupling property. However, the process of which is more complicated and time-consuming. Based on the topology analysis of the PMs, by examining the relationship between partial position and/or orientation (P/O) parameters of the moving platform and the position self-determinism of one actuated branch chain, a concise and practical determining criterion for the MDI of PMs is first presented in the article, i.e., if the partial P/O parameters of the moving platform of a PM can be obtained by one simple or hybrid branch chain that includes at least one actuated joint, the PM behaves certainly motion-decoupling property (either partial decoupling or complete decoupling). Then, a new method for MDI based on the determining criterion is presented. The method is proved to be consistent with the Jacobian matrix method but straightforward and simple. The method also can be used to identify whether a given planar or spatial PM has motion-decoupling property. This work provides an effective method for the motion-decoupling identification of PMs at the level of topology.