为全面考察六维正交并联模拟台可能的误差源,同时避免微分及矢量法建模存在的大量偏导计算,将机构6个支链分别等效为相应的串联机构,根据机构支链的正交特征并结合运动学影响系数的原理建立了较为完备的误差模型。模型包含了铰链点自身加工误差、安装误差,定长杆误差及驱动误差在内的144个误差源。以定义的误差敏感性系数为指标,利用数值仿真分析了所有误差源对末端精度的影响程度,并据此将误差源分为三类:非敏感误差、非完全敏感误差和完全敏感误差。最后,说明了这三类误差在运动学标定过程中与识别参数确定及测量位姿选取的关系。
To avoid the complexity of error modeling based on the method of differential or vector and include the errors as many as possible, the six chains of the simulation platform were regarded as the equivalent series mechanism, respectively. Thanks to the orthogonal feature of the chains and the principle of influence coefficients, the error model of the simulation platform was established. The joint manufacturing errors, instllation errors and actuation errors were taken into account in this model. According to the error sensitivity index, all the 144 errors were classified into three categories: non-sensitive errors, non-wholly sensitive errors and wholly sensitive errors. Finally, the relationship among the three categories of errors, the selected measuring pose and the calibration parameters was explained.