球面拟合法实现机器人与变位机位姿标定

Spherical Fitting Method is Used to Calibrate the Pose Relationship Between Robot and Biaxial Positor

机器人与双轴变位机组成焊接工作站时,为保证协同运动的准确,需确定机器人与变位机间位姿变换矩阵,为此提出一种使用球面拟合法实现机器人与变位机位姿标定方法。首先,双轴变位机俯仰轴和旋转轴旋转不同角度时,记录机器人TCP点在对应位置的位姿信息,并通过遗传算法求得全局最优原点位置,拟合出最优球面;然后,根据原点位置选取6个最优标定点,计算得到变位机基坐标系的单位方向矢量,最终实现机器人与变位机基座标系间位姿标定。使用自主研发的机器人与变位机焊接工作站进行实验验证,并用激光跟踪仪进行有效性验证,实验表明所提出的方法可以有效减小非线性随机误差,其标定误差在0.3 mm以内,可满足焊接的实际要求。

In order to ensure the accuracy of cooperative motion,it is necessary to determine the pose transformation matrix between the robot and the biaxial positioning machine when forming the welding workstation.In this paper,a spherical fitting method is proposed to calibrate the position and pose of a robot and a biaxial allocator.Firstly,when the pitch axis and rotation axis of the biaxial position-shifting machine rotate at different angles,the pose information of the TCP point of the robot at the corresponding position is recorded,and the global optimal origin position is obtained by genetic algorithm to fit the optimal sphere.Then,six optimal reference points were selected according to the origin position,and the unit direction vector of the base coordinate system of the transposition machine was calculated.Finally,the pose calibration between the robot and the base system of the transposition machine was realized.The experimental results show that the proposed method can effectively reduce the nonlinear random error,and the calibration error is within 0.3 mm,which can meet the actual requirements of welding.