Abstract: The dynamic model of the spherical 2-DOF overconstrained parallel manipulator which contains electrical and mechanical subsystem is established by using the screw bond graph. It can obtain the state equations of space parallel mechanism which suitable for control systems. Because of the existence of the passive overconstrained (common constraints or redundant constraints) and active overconstrained (actuation redundancy). There are 43 unknown variables need to be solved, but only 36 equations in the dynamic model. Therefore, in order to solve the problem of passive overconstrained, the displacement of the chains’ end which is caused by chains deformation relative to the center of sphere O is analyzed, respectively. And six supplementary equations of deformation compatibility are added. Aiming at the issue of active overconstrained, the method of driving force optimization is proposed, so the last one supplementary equation is added. Finally, the complete dynamic model of the parallel manipulator is obtained. And then the feasibility and rationality of the method are verified by numerical examples and verification. It also makes a foundation for the following research on the dynamic parameter identification of the parallel manipulator.

Key words: multi-energy domain, overconstrained, parallel mechanism, screw bond graph, dynamic modeling