A nonlinear dynamic hysteresis model with magnetic-thermal-stress-fluid coupling effect for hydraulically amplified magnetostrictive actuator

The hydraulic amplified magnetostrictive actuator (HAMA) has the advantages of large output displacement and fast response speed, but it is affected by coupling effects of electromagnetism, temperature, prestress, fluid, and other factors. In order to accurately analyze its performance, it is necessary to establish a nonlinear dynamic model including the coupling effect of eddy current loss, hysteresis, prestress, temperature, and fluid. First, a nonlinear magnetostrictive model including the magnetic-thermal-stress coupling effect is developed from the perspective of free energy. Based on the conservation of magnetization energy, the influence term of the eddy current is added to the anhysteretic magnetization and a nonlinear dynamic magnetization model including the effect of eddy current is developed. Based on the fluid transmission theory and HAMA’s equivalent dynamic model, a dynamic model of HAMA was established. Finally, a nonlinear dynamic hysteresis model with the magneto-thermal-stress-fluid coupling effect of HAMA is developed, and the performance of HAMA was studied by simulation and experiments. The results show that the output displacement is from −58.2 to 58.2 µm when the control current changes from −2 to 2 A, and the simulation results have a better agreement with the experiment result when the frequency is less than 200 Hz.