Modeling and Control of Piezoceramic Actuators for Nanopositioning

Abstract

Actuators from piezoceramic materials have established themselves in a large number of applications, especially nano-scale positioning tasks because of their high-frequency response behavior and their essentially infinite resolution. However, the potential of these actuators has been impaired by the lack of adequate hysteresis models and control methods to compensate the undesirable non-linear, hysteretic and rate-dependent behavior of piezoceramic materials. In this thesis, representative actuation experiments are conducted on a typical commercially available piezoceramic stack actuator to characterize the rate-dependence of its hysteretic behavior over a large stroke under different loading rates. A strongly physics oriented energy model is implemented to verify its ability in modeling dynamic hysteretic behaviors. By extending this model, a computationally efficient implementation is developed with a drastic improvement in speed. Finally, a preliminary version of the energy model for the piezoceramic material is implemented in an optimal control program to illustrate the features and potential of the method. The implementations constitute the basis for future development of advanced realtime control algorithms for piezoceramic actuators.