Self-Sensing Giant Magnetostrictive Actuator for Active Vibration Isolation

Abstract

Giant magnetostrictive actuator (GMA) are commonly used in active vibration isolation domain for hight frequency response and large output force. GMA has a nonlinear displacement output when disturbed by vibrations. In order to compensate for the nonlinearity and improve the precision of the system, the critical process is the measurement of external disturbances which can be realized with a bridge circuit based on a traditional equivalent circuit model. However, the sensitivity is restricted because of the integral relationship between the force and the open circuit voltage. In this paper, the conception of the dynamic inductance is proposed to optimize the equivalent circuit model that is based on coupled linear magneto-mechanical constitutive equations. Then the measurement for external forces becomes effective with the improvement in the sensitivity through measuring the dynamic inductance. A dynamic simulation is carried out to test the performance of GMA based on the equivalent circuit model. The external dynamic forces can be accurately detected by calculating the impedances in the self-sensing effect of the Terfenol-D.