Hysteresis and vibration compensation in piezoelectric actuators by integrating charge control and inverse feedforward

In this paper we address the problems of hysteresis and vibrations that limit the accuracy of piezoelectric positioners. It is widely known that the use of charge control significantly reduces hysteresis, thus enabling high-accuracy positioning during low speed operations. However, charge control is unable to reduce vibrations that limit the positioning bandwidth. Our main contribution is to overcome this bandwidth limitation by augmenting charge control with inverse feedforward to compensate for vibrations, resulting in a high-bandwidth, high-accuracy positioning system. We apply this integrated method to a piezoelectric tube actuator and experimental results are presented to illustrate the positioning improvements with the proposed integrated approach.