平面两自由度并联机构运动学标定研究

Kinematics Calibration of a 2 DOF Parallel Planar Mechanism

提出一种平面两自由度并联机构,由运动学分析得出机构的运动学解析解,针对该机构提出了一种运动学标定的新方法。与传统的并联机构运动学标定方法不同,该方法无需测量末端执行装置的全部位置和姿态,只需测量末端执行装置在工作空间内的一系列位移量;通过使用万能工具显微镜作为检测工具,从而无需额外安装位移传感器。建立了使得距离测量误差平方和最小的非线性规划数学模型,并通过MATLAB软件的优化工具箱进行求解。实验证明了该方法的有效性,并得出了机构运动学参数的最优值。实验结果表明,标定后机构精度明显提高,标定方法可靠。

A 2 DOF parallel mechanism was presented here. The explicit formulas of kinematic solutions were derived by the forward kinematic analysis. An efficient method was presented to calibrate the parallel mechanism. Instead of measuring all or partial position and orientation of the end effecter, the kinematic parameters of the mechanism were calibrated by measuring a serial of displacements of its end effecter, which moved from one point to another in its workspace. The universal tool microscope rather than extra sensors measured those displacements. The optimal kinematic parameters were obtained by solving a nonlinear programming model, which minimized the measurement errors of the end effecter, by using Matlab optimization toolbox. Experiments had been performed to show the validity of the calibration method and to find out the optimal kinematic parameters. The experimental results show the accuracy of the mechanism is greatly improved. The method is in effect.