基于球杆仪检测信息的并联机构运动学标定

KINEMATIC CALIBRATION OF THE PARALLEL MECHANISM USING DOUBLE-BALL-BAR SYSTEM

由于并联构型装备难于实现全闭环反馈控制,使运动学标定成为一项具有显著经济价值并能非常有效提高并联构型装备精度的手段,运动学标定通常包括误差建模、测量、辨识和补偿4个环节。基于以上因素,以5自由度混联机械手TriVariant为对象,研究一种基于球杆仪检测信息的运动学标定方法。首先建立球杆仪测量值与影响末端可补偿位姿误差的几何误差源的映射关系,并给出可辨识条件。在此基础上,以误差参数辨识矩阵条件数为评价指标,探讨合理设置球杆仪安装位置和数目的方法。最后,计算机仿真和试验验证了所提出方法的可行性和有效性,并指出仍然需要解决的若干问题。

Since that it＇s difficult to realize full closed-loop feedback control, kinematic calibration becomes a method to heavily gain economic value and effectively enhance the accuracy of parallel kinematic machine. In general, kinematic calibration consists of four steps, i.e. error modeling, measurement, identification and compensation. A double-hallbar （DBB） based kinematic calibration of the 5-DOF reconfigurable hybrid robot named TriVariant is prespnted. The first order error mapping function is formulated to link the measured data to the geometric source errors affecting the compensatable pose accuracy. The issue to place a DBB mount is also investigated in order to achieve sufficient robustness of parameter identification. The effectiveness of the proposed approach is verified by both computer simulation and experiments. Some key issues for the further enhancement of the pose accuracy are also addressed by examining the experiment results.