Dynamic Performance Optimization of a Novel 8-SPU Parallel Walking Mechanism

Dynamic performance as one of the important properties of the parallel mechanism cannot be ignored, which is usually illustrated through dynamic performance analysis with the aid of index. Therefore, to develop reasonable dynamic performance indices is of great theoretical and practical significance for the parallel mechanism. In this paper, the above issues are discussed by taking the parallel mechanism designed by our research group as a study object. First, on the basis of considering the driving motor, kinematics dexterity and dynamic dexterity based on the global kinematics condition index and the global dynamic condition index are analyzed, respectively, in the workspace. Second, a novel diagonally dominant index (DDI) is presented in terms of the equivalent inertia parameter in joint space, and the proposed approach gives full consideration to minimize the inter-chain coupling effects. Furthermore, the parallel mechanism is optimized by means of taking the volume of the workspace, the global kinematics condition index, the global dynamic condition index, and the diagonally dominant index as objective functions. The optimization result shows that the larger workspace, higher dexterity, and smaller DDI are obtained to further improve the work capability and dynamic property of the mechanism. Finally, a real and novel 8-SPU (spherical pair, prismatic pair, and universal pair) parallel walking mechanism is manufactured in terms of the optimized architecture parameters.