一种利用位置误差模型的机器人位姿标定方法

A Robot Pose Calibration Method Using Position Error Model

针对机器人位姿标定模型中位置和姿态数据的权重不合理导致参数识别精度低甚至发散问题,给出一种直接基于末端位置坐标测量的机器人位姿标定方法,避免了位置和姿态数据量级不同对参数识别精度的影响。采用指数积方法,建立一种包含3点位置信息的机器人运动学模型。通过对运动学模型取微分,利用指数映射微分公式推导出机器人末端3点位置误差与几何参数误差之间映射关系的显示表达并给出参数误差识别方法。采用激光跟踪仪作为测量设备,以UR5机器人为标定对象进行运动学参数标定和验证试验。试验结果表明,机器人末端位置误差模和姿态误差模的平均值分别降低了90%和92%。

Unreasonable weights of position and orientation data in a robot pose calibration model may lead to low accuracy or even divergence of parameter identification.A robot pose calibration method is presented directly based on the position measurement of an end-effector,avoiding the influence of different magnitudes of position and orientation data on parameter identification accuracy.A robot's kinematic model based on three-point position information is established by using the product of exponential formula.By differentiating the kinematic model and then employing the explicit expression of differentials of exponential mapping,the explicit expression of the mapping relationship between three-point position errors of the end-effector and its geometric parameter errors is derived,and the parameter error identification method is introduced.By taking a laser tracker as the measuring equipment,the UR5 robot is used to perform the kinematic parameter calibration and verification tests.The results indicate that the mean values of the modulus of position error and orientation error are reduced by 90%and 92%,respectively.