一种可实现两平动自由度并联机构运动学标定方法

针对一种两平动自由度并联机构，提出了一种识别几何参数误差的方法，能有效补偿机构的动平台位姿耦合误差．忽略两组平行杆的相对杆长误差，将机构简化成仅含转动副的5杆铰接机构，建立了含有8个几何参数误差模型，即4个杆长误差和4个主动关节铰点坐标误差．研究表明，并联拓扑结构使动平台沿两个正交轴的位置误差和姿态误差具有强耦合性．给出标定坐标系原点，通过仅检测动平台沿标定坐标系任一单轴的位置误差，识别出系统的几何误差全集．计算机仿真和实验结果表明，通过这种方法，可使机构的动平台定位精度达到0．05mm．

Kinematic Calibration of a 2 Degree of Freedom Translational Parallel Robot

An Approach is presented to identify the geometric errors of a 2 degree of freedom (2-DOF) transla tional parallel robot and thereby to compensate the position errors and pose errors of its end-effector in a timely and cost-effective manner. Assuming that the relative length errors of two sets of parallelograms are sufficiently small,the robot is simplified into a general revolute-jointed 5-bar linkage with 8 geometrical parameters in terms of the length errors of the links and coordinate errors of the actuated joints. It was found that position errors and pose of the end-effector along two orthogonal axes were strongly coupled due to the topological structure of parallel architecture. This property allows for the identification of the entire set of geometric errors by measuring only the position errors of the end-effector along a single axis, provided that the origin of the calibration frame is defined at the initial configuration. Both the computer simulation and experimental results showed that 0. 05 mm positioning accuracy of the end-effector could be obtained by this method.