考虑测量空间的机器人绝对定位精度标定

Calibration of Absolute Positioning Accuracy of Robots Considering Measurement Space

相较于机床,工业机器人绝对定位精度较低,难以满足磨削等高精度加工工艺的需求,较大地限制了其应用拓展。针对该问题,本文重点考虑空间测量位置的优化与选择,提出了一种基于距离精度的机器人绝对定位精度标定方法。首先在空间测量位置对于测量精度影响分析的基础上,采用了雅克比矩阵条件数来定量描述机器人运动性能。结合机器人关节运动特征,分别给出了关节空间与末端笛卡尔运动空间内的机器人优化测量位置范围。然后采用MD-H运动学方法构建了机器人绝对定位精度误差模型,引入距离精度方法,通过距离误差计算避免了坐标系转换误差。最后基于KUKA机器人实验平台开展了标定实验,结果表明机器人平均绝对定位误差从标定前的1.191 mm降低到了0.096 mm,有效验证了方法的有效性。

Comparing with the CNC,absolute positioning accuracy of the industrial robots is low,and it is difficult to meet the requirements of high-precision machining processes such as grinding,which greatly limits its application development.Aiming at this problem,a calibration method for absolute positioning accuracy of robots based on the distance accuracy is proposed,which takes the optimization and selection of spatial measurement positions into consideration.Firstly,based on the influence of the spatial measurement positions on the measurement accuracy,the Jacobian matrix condition number is used to quantitatively describe the motion performance of the robot.Combining with the motion characteristics of robot joints,the optimal measurement spaces of the robot in joint space and Cartesian space are given.Then the MD-H(Modified D-H method)is used to construct the error model for the robot absolute positioning accuracy.The distance accuracy method is introduced,which is used to avoid the coordinate transformation error.Finally,based on the KUKA robot experimental platform,the calibration experiments were carried out.The results show that the average absolute positioning error of the robot decreases from 1.191 mm to 0.096 mm,which effectively validates the effectiveness of the calibration method.