基于相对精度指标的机器人运动学校准

Kinematic calibration for robots based on relative accuracy

针对工业机器人在激光切割、弧焊等应用领域对相对精度的指标要求,结合鲁棒的极小极大优化理论,提出基于相对精度指标的运动学结构参数校准方法.通过最小化3个靶球对应的最差相对定位误差,保障前、后两位型间的相对定向精度,构建包含约束的非线性优化问题;使用二次序列规划方法对原问题进行近似,通过主二元子梯度算法在满足不等式约束的条件下快速搜索局部最优解,实现对由于部件制造和装配等环节引入机器人结构参数误差的辨识.进行补偿并精度验证后的实验结果表明,六轴机器人IRB2600的相对定位及定向精度分别提升了67.98%和24.32%,七轴机器人IRB14000分别提升了90.61%和74.61%.

A kinematic calibration method for structure parameters based on the relative accuracy was proposed by using the robust minimax optimization theory in order to meet the requirements of high relative accuracy for industrial robots in the application fields of laser cutting, arc welding and so on. The relative orientation accuracy between two successive configurations was guaranteed by minimizing the worst relative positioning errors corresponding to the three target spheres, and a nonlinear optimization problem with constraints was established.Then the original problem was approximated by using a quadratic sequence programming method, and a primal-dual subgradient algorithm was introduced to search the local optimal solution quickly under inequality constraints. The structural parameter errors of the robot introduced in the process of manufacturing and assembly were identified. The compensation and verification were conducted. The experimental results showed that the relative positioning and orientation accuracies of the six-axis robot IRB2600 increased by 67.98% and 24.32%, and the seven-axis robot IRB14000 improved by 90.61% and 74.61%, respectively.