Experimental characterization and modeling of stress-dependent hysteresis of a giant magnetostrictive actuator

The hysteresis nonlinearity of giant magnetostrictive actuator (GMA) is stress-dependent. In this paper, laboratory experiments were performed to characterize the stress-dependent hysteresis properties of a GMA under different compressive stresses ranging from −11.3 MPa to −24.3 MPa and harmonic current excitation with amplitudes from 0.6 A to 1.2 A. The experimental results showed that remarkable changes in peak-peak displacement responses, hysteresis loop width and hysteresis loss occurred with the increasing of compressive stress; no significant changes in coercive current were observed. Based on the analysis of experimental data and discussion of the influences of the weights of Modified Prandtl-Ishlinskii (MPI) on the characteristics of hysteresis loops, a stress-dependent Prandtl-Ishlinskii (SDPI) model was proposed by extending the MPI model to describe the effects of compressive stress, in which the weights of deadzone operators are extended as function of compressive stress. Good agreements were obtained between the model simulation results and the experimental data. Additional model validations were given by the performances of tracking control experiments with an inverse feedforward controller. The experimental results have clearly shown that the inverse SDPI is effective for compensating stress-dependent hysteresis including major and minor loops.