Combined control for GMA with modified P-I model and hysteresis phase compensation

Hysteresis nonlinearity is the inherent property of Giant Magnetostictive Material (GMM), Prandtl-Ishlinskii (P-I) model is an effective way to describe and compensate the hysteresis of Giant Magnetostictive Actuator (GMA), while one of the drawbacks of P-I model is the narrow applicable frequency domain. In this paper, A compounding feedforward compensation method with modified P-I model and hysteresis phase compensation is proposed to extend the applicable frequency domain of P-I model and reduce the hysteresis loop of GMA, and the validation of model is examined by comparing the input-output relations of model and experimental data under different frequencies. Finally, a compound close-loop controller with hysteresis phase compensation, inverse modified P-I model and PID feedback control is designed to compensate the hysteresis. The experiments show that hysteresis nonlinearity of GMA is reduced effectively under a wide frequency range from 14.5 %~ 67.2 % to 0.43%~ 2.71%.