Path Error Measurement and Compensation of Precision Working Table

Ultra-precision machining is a key technology developed with the process of manufacturing. At the point of micro driving, regulating the accuracy of machine tool with smart materials that can generate micro movement to an extent of nanometer level is often introduced to satisfy the required precision. Aiming at reducing the path error of a precision working table driven by an AC servo motor, the measurement of the dynamical characteristics of the system was carried on by a laser interferometer. Error signal was acquired, decomposed and then analyzed to match with various phenomena, such as backlash, stick-slip and self-excited vibration during the motor processes at different speeds. Based on this, a giant magnetostrictive actuator(GMA) was designed to act as a compensator to minimize the typical path error. The hysteresis nonlinearity of the GMA was controlled effectively by PID control techniques. Experimental results showed great improvements of the tracking accuracy, which proved the feasibility of the proposed method.