Research And Compensation Control On Constitutive Nonlinear Of Giant Magnetostrictive Actuators

Giant magnetostrictive actuators, characterized by large strain, high force and fast response and so on, have a wide range of potential application in super-precision positioning, robotics, and vibration control, etc. However, the relation between the input magnetic field and output displacement for magnetostrictive actuators exhibits the hysteresis nonlinearity, which presents a challenge in the applications of actuators.A number of techniques have been considered for quantifying the hysteresis and constitute nonlinearities inherent to the relation between input field and the generated magnetization and strain. For Terfenol-D actuators, these include Preisach models, domain wall models based on the magnetic theory of Jiles and Atherton and free energy models. For actuator characterization and control design, crucial requirements for the models include automatic closure of biased minor loops, flexibility with regard to temperature and frequency, and sufficient efficiency to permit real-time implementation. In these three models, only free energy models have those characters. Research on free energy models for hysteresis is seldom reported systematically.Hysteresis exhibited by magnetostrictive actuators is rate-independent when the input frequency is low and it can be modeled by a free energy model. It becomes rate-dependent when the input frequency gets high due to the eddy current effect and the magnetoelastic dynamics. In this case, a new dynamic hysteresis model, consisting of a Preisach operator coupled to an ordinary differential equation in an unusual way, is proposed. Its various system-theoretic properties are studied. Algorithms for simulation of the model are also studied. Parameter identification methods for both the free energy hysteresis model and the dynamic model are investigated. Inverse compensation techniques for the dynamic free energy model for hysteresis are...