含约束支链的冗余驱动并联机构动力学性能优化

全驱动并联机构可以通过增加约束支链或关节实现机构驱动冗余。为了研究约束支链与关节对冗余驱动并联机构动力学性能的优化问题,分析对比了冗余驱动并联机构6P-US+UPU与非冗余驱动并联机构6P-US机构的动力学特性,研究了约束支链对冗余驱动并联机构动力学性能的优化机理。基于虚功原理建立了6P-US机构和6P-US+UPU机构的动力学模型,提出具有明确物理意义的冗余驱动并联机构动力学性能指标,分析了约束分支对机构动力学性能的影响,并结合数值算例对两种机构动力学性能进行了对比分析。结果显示,支链约束提高了机构动力学性能,而支链质量会降低机构动力学性能。

Dynamics Performance Optimization for Redundantly Actuated Parallel Manipulator with Constraint Branch

The full-actuated parallel manipulator can realize the actuation redundancy of manipulator by increasing one or more constraint branch chain or joint. In order to analyze the optimization of the constrained branch chain and joint to the dynamics performance of the redundantly actuated parallel manipulator, a deep analysis and comparison of dynamics characteristics between redundantly actuated parallel manipulator 6P-US+UPU and non-redundantly actuated parallel manipulator 6P-US were conducted, and the optimization mechanism of constrained branch chain on the dynamics performance of redundantly actuated parallel manipulator was discussed. Based on the principle of virtual work, the dynamics models of non-redundant manipulator 6P-US and redundant manipulator 6P-US+UPU were established respectively. Then according to different influence factors on the dynamics, dynamics performance indexes of redundantly actuated parallel manipulator with clear physical meanings were proposed. The influences of constrain branch chain with and without mass on the different dynamics performance indexes of the manipulator were analyzed subsequently. Prototypes of the two manipulators with specified inertial and geometric parameters were given and numerical comparisons of dynamics performance was carried out finally. The results showed that the branch constraint improved the dynamic performance of the mechanism, while the quality of the branch would reduce the performance.