Analysis and simplification of the rigid body dynamic model for a 6-UPS parallel kinematic machine under the uniform motion condition

Due to the closed-loop mechanism, the rigid body dynamic model of the parallel kinematic machine (PKM) is very complex and difficult to be used in the real-time control system. Under the uniform motion condition, this paper presents a study on the analysis and simplification of the rigid body dynamic model for a 6-UPS PKM. Firstly, the dynamic model is developed by Newton-Euler approach and decomposed into fifteen subitems. According to the working situation, the dynamic characteristics of the subitems are analyzed by the means of numerical simulation. Finally, the simplifying strategies of the dynamic model are presented and verified. It is proved by the verification results that the simplifying strategies can improve the computational efficiency greatly and only bring small simplifying error.