Key Technology Of Industrial Serial Robot Calibration

Industrial robot contemporarily raises its popularity among application and research field. By changing the tool mounted on the last joint of a robot, people can complete diverse processing task with one robot. Thus calibrating tool coordinate system means significant to both accurate movement and efficient processing of a robot. Besides, increasingly demanded Off-line programming asks industrial robots for a better performance in position accuracy.First, build robot joint coordinate system on D-H kinematic model and general kinematic model respectively. Introduce robot forward kinematic function, describe tool coordinate under robot base coordinate, and illustrate how to calibrate tool coordinate with a fixed point and a set of different poses.Geometric parameter errors take the biggest share in those factors that decrease robot position accuracy. Calibrating robot kinematic model can modify robot joint kinematic method to raise robot accuracy. On the basis of robot kinematic models, error parameter models are derived by Jacobian matrix. Use least square method through a Matlab routine to solve error parameter model and obtain the specific error.Design an elaborate experiment using a laser tracker to get the real position of a robot end effector and get the deviation between real position and nominal position. Establish a virtual end-effector coordinate to reduce errors brought in by measurement. Input the position error into the Matlab routine and acquire the error parameters. Compensate the geometric parameters in the robot controller, analyze the results of calibration, compare the calibration under two kinematic models. A real test taking a new set of configuration to verify the calibration method proves the whole calibration method to be effective.