Development of a micro-depth control system for an ultra-precision lathe using a piezo-electric actuator

Micro-positioning systems using piezo-electric actuators have very wide applications, for example as in ultra-precision machine tools, optical devices and measurement systems. In order to keep a high-precision displacement resolution, they use a position sensor and feed back the error. From the practical point of view, high-resolution displacement sensor systems are very expensive and it is difficult to guarantee such sensitive sensors to work properly in the hard operational environment of industry. In this study, a micro-depth control system which does not require a position sensor but which uses piezoelectric voltage feedback has been developed. It is driven by hysteresis-considering a reference input voltage which is calculated by computer, and then uses actuator/sensor characteristics of piezo-electric materials. Results of experiments indicate a fast and stable response of the micro-positioning system and suggest it is an efficient technique for controlling the piezo-electric actuator. (C) 1997 Published by Elsevier Science Ltd.