一种新型虚拟中心并联机构的误差灵敏度分析

Error Sensitivity Analysis of Novel Virtual Center Mechanism with Parallel Kinematics

采用基于空间误差矢量链的误差建模方法,对一种新型虚拟中心并联机构进行了误差建模,获得各几何误差参数与终端输出误差参数之间的映射函数,在所建立的误差模型的基础上,分析各几何误差参数对终端输出误差参数的局部灵敏度系数和全局灵敏度系数,并将相应的误差灵敏度以图谱的形式直观的展现出来,通过对相应的分布图谱进行分析,得出各关键几何参数对该虚拟中心并联机构输出精度的影响程度,从而有效地指导机械设计阶段各零部件的公差等级的选择以及控制阶段系统输出误差的限定。

The error model of a novel virtual center mechanism with parallel kinematics is established based on the modeling method of spatial error-vector chains.Thereafter,the mapping functions between the geometric error parameters and the output error parameters are generated.On the basis of the error model,the local sensitivity coefficient index and the global sensitivity coefficient index of each geometric error parameter are derived and graphically presented in atlases.Based on these atlases,the geometric error parameters＇ influence on the output accuracy of the virtual center mechanism is identified numerically.The results contribute a lot to the determination of the parts＇ tolerance and the output error of the control system.