Comparison of Three Compensation Methods for the Touch-trigger Probe Pretravel Errors

On-machine inspection (OMI) system has been used extensively for automatic setting of the workpiece and determination of kinematic error in machine tool. There is a necessity not only for knowledge of touch-trigger probing error characteristic, but also for the compensation method of probe error because probing error is an important component of system errors. The comparison of compensation accuracy of three compensation methods is presented. To compensate the touch trigger probe pre-travel errors the calibration experiments with a reference sphere are conducted. Subsequently, the calibration data are used in three compensation methods that the bilinear interpolation method, the bicubic Coons pitch interpolation method and the neural network method. Finally, the validate experiments are conducted on the OMI system, and the compensation results show that the bicubic Coons pitch interpolation method is the most accuracy compensation method.