利用冗余支链测量信息,对一类带冗余支链并联机器的运动学参数进行自标定。通过矢量闭环微分法,建立冗余支链运动学误差模型,并通过多个位姿处误差传递矩阵的组合,得到自标定的辨识雅可比矩阵。针对部分运动学参数误差辨识性差的问题,提出一种基于辨识雅可比矩阵各列线性相关性分析的辨识性分析方法,得到可辨识的运动学参数误差线性耦合式,并简化误差辨识方程使辨识性提高。最后利用冗余支链角度编码器测量信息,完成一个4RRR冗余并联机器的运动学自标定,仿真结果显示,基于冗余支链的运动学自标定能有效提高冗余支链和机构终端运动精度。
Based on the measuring information of the redundant kinematic chain,the kinematic self-calibration of a kind of parallel kinematic machines(PKMs) with redundant chain is presented.Based on differential of the closed-loop vector chain,the redundant chain's kinematic error model is obtained,and the identifying Jacobian matrix of self-calibration is got by combining the error transfer matrixes in a few poses.To solve the difficult identifiability problem of some kinematic parameter errors,an identification analysis method is presented based on the linear correlation analysis of the identifying Jacobian matrix' column vectors,and by this method,the kinematic parameter errors' identifiable linear combinations can be got and the identification equation can be simplified to enhance the identifiability.Finally,based on the measuring information from the incremental angle encoder of the redundant chain,the self-calibration of a 4RRR redundant PKM is completed.Simulation result shows that the kinemamtic self-calibration based on redundant chain can effectively improve the motion accuracies of the redundant chain and the end-effector.