Control of Smart Actuators

Hysteresis in smart materials hinders wider applicability of such materials in actuators and sensors. In this dissertation we study modeling, identification and control of hysteresis in smart actuators. While the approaches are applicable to control of a wide class of smart actuators, we illustrate the ideas through the example of controlling a magnetostrictive actuator. Hysteresis exhibited by magnetostrictive actuators is rate-independent when the input frequency is low and we can model it by a Preisach operator. It becomes rate-dependent when the input frequency gets high due to the eddy current effect and the magnetoelastic dynamics. In this case, we propose a new dynamic hys-teresis model, consisting of a Preisach operator coupled to an ordinary differential equation in an unusual way. We establish its well-posedness and study its various system-theoretic properties. Existence of periodic solutions under periodic forcing is proved. Algorithms for simulation of the model are also studied. Parameter identification methods for both the Preisach operator and the dynamic model are investigated.