Dynamic Modeling and Position Control of a Piezoelectric Flextensional Actuator

Abstract

Many smart material actuators suffer in either insufficient force generation or displacement range, two important performance metrics in actuator design. Piezoelectric flextensional actuators were conceived to bridge the gap between displacement and force, offering acceptable performance in both categories. Their displacement range and load carrying capability make them suitable for many applications requiring micrometer-scale displacements. Typical applications require closed-loop control algorithms to achieve good resolution at these displacement levels. In this thesis, an open-loop model of a commercially available, piezoelectric flextensional actuator and drive system was designed. This model was used to design a feedback control system for reference tracking applications. The control system was built and verified with the physical actuator. Its performance was shown to agree with the model simulations. Both the model and the physical system had negligible overshoot, settling times of less than 30 milliseconds, and zero steady-state error in response to step inputs.