冗余驱动支链对3RPS 并联机构刚度的改善

摘要

在考虑雅可比矩阵变化与动平台姿态偏移之间映射关系的基础上，基于螺旋理论和矢量微分法建立了3RPS 并联机构末端位姿偏移与支链构件变形之间的映射模型。首先采用螺旋理论和矢量微分法分析了支链各构件刚度与整个支链刚度之间的关系，然后建立了3RPS 并联机构的瞬时刚度模型，并分析了雅可比矩阵的变化对机构刚度的影响。对冗余驱动支链改善并联机构刚度的原理进行了分析，建立了冗余驱动并联机构的整机刚度模型。仿真分析和实验验证，冗余驱动支链确实能够改善并联机构的刚度。%Considering the relationship between the changes of the Jacobian matrix and the orien-tation deviation of the moving platform,the mapping model between the 3RPS PKM end-effector off-set and the deformation of the branches was established by using the vector differential method,based on the screw theory.The functional expression of the rigidity of the chain and its components was de-rived,and then the instant stiffness model of the 3RPS PKM was built up.The influences of the chan-ges of the Jacobian matrix on the stiffness of the PKM were analyzed.The theories that the redundant actuating leg could increase the stiffness of the PKM were discussed,and were also verified by the simulation and the tests.