Contrasting study of on-line calibration technology for robot coordinate measurement system

The parameters of the robot have been changed due to the rising of machine temperature and the external environment variances during the continuous moving of the robot, which greatly enlarge the error of the robot coordinate measurement system, therefore the changes of the parameters must be compensated. This paper compares two techniques used in robot parameters rapid calibration: based on measurement space fixed-point real-time robot parameters rapid calibration technology and based on space constant distance real-time robot parameters rapid calibration technology. Both of the techniques realize with the same method. First, we should solve out the robot model parameters in reversal after changing based on the relationship of the robot motion model, parameters and fixed-point coordinate (constant distance).Then figure out the measuring results variation caused by the change of robot parameters by forward calculation with these parameters. At last, amend the final measuring results to realize real-time robot parameters rapid calibration. Experiments prove that techniques based on measurement space fixed-point real-time robot parameters rapid calibration can improve system accuracy from 0.5mm to 0.2mm above, while those based on space constant distance real-time robot parameters rapid calibration can reduce the system error from 0.5mm to 0.18mm. So, the accuracy compensate ability of the latter one is slightly higher than that of the former one by 0.02mm.