大型工业机器人运动学标定及精度补偿方法

Kinematics Calibration of Large Industrial Robot and Precision Compensation Method

将大型工业机器人引入航天制造领域,能够实现航天装备的高精度和可靠性。为了提高机器人绝对定位精度,更好地适应航天领域产品装配需求,基于改进的D-H(MD-H)模型,提出了大型工业机器人运动学标定及精度补偿方法。首先在误差建模中加入了坐标系转换误差和靶球安装误差,建立了更为完善的标定误差模型。然后通过激光跟踪仪对末端靶球进行测量来获得实际位姿数据,并采用改进的迭代最小二乘法辨识出误差参数。最后根据计算误差对机器人进行修正与补偿,完成运动学标定过程。为验证辨识方法的有效性,以KUKA KR1000 Titan大型工业机器人为研究对象进行仿真和实验。结果表明,经过标定补偿后的机器人末端平均定位误差由1.122mm降低到0.340mm,平均定位精度提升了约70%,补偿后机器人的绝对定位精度得到明显改善。

Introducing large industrial robots into aerospace manufacturing can achieve high precision and reliability of aerospace equipment.The kinematics calibration of large industrial robot and precision compensation method was suggested based on the modified D-H(MD-H)model to improve the absolute positioning accuracy,which can better adapt to the product assembly requirements of the aerospace field.There was a more complete error parameter identification model by adding the coordinate system transformation error and target ball installation error.Then the method using a laser tracker got the position of robot terminal by the target ball attached to the flange plate.The robot terminal error model was calculated by improved iterative least square method.Finally the compensation can be made to the robot terminal to complete the calibration.In order to further verify the validity of the identification algorithm,KUKA KR1000 Titan industrial robot was used for simulation and experiment.The results illustrate that the average error decreased from 1.122mm to 0.340mm and the average positioning accuracy has increased by about 70%.The absolute positioning accuracy rate significantly improved with the process of calibration compensation.