Study on High Speed Feed Drive System for Machine Tools -Improvement of PID Control Parameter-
Toshitake Tateno* and Hiromu Nakazawa**
*Tokyo Metropolitan University, Minami Ohsawa 1-1, Hachiohji, Tokyo, 192-03 Japan
**School of Science & Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku-ku, Tokyo, 169 Japan
In order to realize feed rate of 20m/min for cutting operation of medium and large size machine tools, a new high speed and high accuracy feed drive system which has a servomotor and ballscrew combined with a hydraulic actuator has been developed. As stated in a previous paper this system can drive ten times faster than conventional rate with considerable accuracy. This paper describes a method for determining optimal PI control parameters of the electric servomotor and PD control parameters of the hydraulic actuator. In order to make the best use of the hydraulic actuator a new function which compares the force of electric servomotor with that of hydraulic actuator is proposed. The experimental results show that the controlling parameters determined by this method reduce motor power and the method is proved to be effective.