Hysteresis and creep compensation for piezoelectric actuator in open-loop operation

Piezoelectric actuators are frequently used nowadays in a wide variety of positioning devices. However, a major deficiency of piezoelectric actuators is that their open-loop control accuracy is seriously limited by hysteresis and creep effects. This paper describes a method for simultaneous compensation of the hysteresis and creep of piezoelectric actuator based on an inverse control in open-loop operation. The basis of the inverse control is formed by a hysteresis mathematical model and a creep model, which can describe precisely two phenomena. The method of solving inverse models of hysteresis and creep is described detailedly. Finally, a tracking control experiment of piezoelectric actuators for a desired trajectory is performed according to the proposed method and the experimental results demonstrate that the positioning precision is noticeably improved in open-loop operation compared to the conventional open-loop control without any compensation.