Investigation on Open Loop Position Control of Amplified Piezoactuator

Abstract

Amplified piezoelectric actuators (APAs) consist of stacked piezoelectric actuators inside a flexural mechanical amplifier which helps in amplifying the displacements of the piezostacks in static and dynamic conditions. Accounting for their precision movement and dynamic characteristics, these actuators are extensively used in micropositioning, active damping, and microactuation applications. In this paper, FEM analysis of mechanical flexural amplifier of APA230L piezoactuator was performed to estimate its stiffness in the horizontal direction and to estimate its displacement amplification factor. The stiffness of the flexural amplifier was found to be 7.089 N/µm, and the displacement amplification factor of the flexural amplifier was estimated to be 4.05. Piezoelectric stack actuators exhibit hysteresis behavior between applied voltage and the resulting displacement and the same behavior was amplified by the flexural—a displacement amplifier. The hysteresis behavior of the piezoelectric stack actuator was modeled using Bouc-Wen model and the inverse Bouc-Wen model was used to estimate the drive voltage required for the desired displacement. Open loop tracking control of APA230L piezoactuator was carried out for different desired displacement profiles and a maximum of 4% error was observed between the desired and the experimental displacements obtained.