Modeling and Control Issues Concerning Smart Materials with Hysteresis
This research program focuses on modeling and control issues concerning certain smart material actuators utilized in nonlinear regimes. Piezoelectric, electrostrictive and magnetostrictive materials all exhibit various degrees of hysteresis and nonlinear dynamics at high drive levels. The accurate and efficient quantification of these effects and their incorporation in control design are necessary to attain the full capabilities of the materials.
Our research efforts have centered on the development of unified modeling techniques and corresponding control methods for ferroelectric and ferromagnetic materials which exhibit hysteresis and nonlinear dynamics. The models are based on the characterization of energy losses due to pinning sites in the material which inhibit domain wall motion and subsequent changes in the magnetization or polarization. In applications which require high drive levels, linear control methods prove ineffective due to phase delays resulting from unaccommodated hysteresis. For such regimes both nonlinear optimal control formulations and linear methods which utilize model-based inverse compensators have been developed. An integral component of both the model development and control implementation involves the design and implementation of validation experiments.
CRSC researchers participating in this project include R.C. Smith and his graduate students working in collaboration with scientists at Iowa State University and Lockheed Martin.
