精密小型Hexapod并联机器人标定实验及精度分析

为了提高精密小型Hexapod并联机器人的运行精度,对机器人进行了标定实验及精度分析.推导了Hexapod机器人结构参数的误差模型、设计了标定步骤和算法,并在三坐标测量机上对机器人进行标定实验;从机构角度对Hexapod机器人的间隙误差来源进行了分析,并推导了间隙误差对机器人位姿误差的映射关系数学模型;推导并分析了计算过程中最小二乘误差、牛顿-拉普森迭代误差的数学模型,分析了机器人结构参数的辨识精度.标定实验结果表明：经过误差补偿,机器人位姿坐标的最大位移误差由0.267 6 mm降为0.010 5 mm;最大转角误差由0.006 8 rad降为0.001 1 rad.Hexapod机器人标定及精度分析方法对于开发精密型并联机器人具有参考价值.

Calibration Test and Precision Analysis of Small-Sized Hexapod Parallel Manipulator with High Accuracy

To improve the accuracy of small-sized Hexapod parallel manipulator, calibration test and precision analysis were conducted in this paper. An error model of Hexapod was derived, and calibration procedure was designed and calibration test was conducted on 3-coordinate measuring machine （CMM）. An analysis regarding the error sources of Hexapod was also conducted from the mechanical angle, and a mapping model from the gap error to the pose error of Hexapod was derived. Then the error models of least square method and Newton-Raphson iteration method in the calculation were derived and analyzed, and the identification accuracy for geometric parameters of Hexapod was analyzed. The calibration results show that after calibration, the maximum translation error of Hexapod manipulator declined from 0.267 6 mm to 0.010 5 ram, and the maximum rotation error declined from 0.006 8 tad to 0.00l 1 rad. The calibration method and precision analysis method of Hexapod have a reference val- ue for developing high precision parallel manipulators.