Design, identification, and control of piezoactuated positioning mechanism based on adaptive inverse method

Precision positioning mechanisms using piezoelectric stack actuators have a very wide range of applications. However, loss of tracking positioning precision in piezoelectric actuators occurs as a result of hysteresis during long-range applications and creep effects. This paper proposes two models that can simultaneously describe the hysteresis and creep phenomena of a piezoelectric actuator. Based on the hysteresis model and creep model, an adaptive inverse control approach is presented for improving the tracking performance of piezonanopositioning. The inverse controller is identified by using least mean square algorithm. The realization of the adaptive inverse controller for the linearization of a piezoelectric actuator is formulated. Finally, a tracking control experiment of piezoelectric actuators for a desired trajectory is performed according to the proposed method. The experimental results demonstrate that the positioning precision is noticeably improved in open-loop operation compared with the conventional open-loop control without any compensation.