Tool coordinate system calibration for jet printing robot

A robot tool coordinate system calibration method based on the laser tracker is presented.The robot base coordinate system is determined by the laser tracker,and then the coordinate systems of the robot and laser tracker measurement are unified.By using the robot kinematic equations,the transformation relationship between the robot end-effecter coordinate system and its base coordinate system is obtained.The robot tool coordinate system is measured and fitted by the laser tracker,and then the parameters of TCF(tool control frame)are preliminarily established using the coordinate transformation.Using the single axis rotation of the robot,the TCP(tool centre point)is corrected with the TCF and then is ultimately determined.Finally,the errors are calculated by the robot's reorientation movement.Experiment results show that the RMS errors for x,y and zcoordinates after correction are 0.127 1,0.141 3and 0.117 4mm,respectively;the accuracy is 2.5times as much as that before correction.