Improved control strategy for magnetostrictive-based vibration suppression method using negative capacitor in flexible multiple-degree-of-freedom structures

When using a magnetostrictive transducer for semi-active vibration suppression, the amplitude and phase of the induced current are key factors because they directly determine the control force exerted by the transducer. In conventional semi-active vibration suppression methods, a target current derived from active control theory is employed to modify the induced current by switching the circuit state. The control circuit used in the conventional method includes a negative capacitor to amplify the induced current and an inductor-capacitor circuit to inverse it as desired. Despite using a machine learning model to predetermine the current amplitude, the conventional control strategy lacks a versatile and simple design. To improve the control strategy, a target current allowable area is introduced in this study to define the limits of the induced current. The boundaries of this allowable area were set by the target currents derived from the linear quadratic control theory. The vibration suppression performance and influence of the time delay were predicted using a mathematical model of a 10-bay truss structure. The effectiveness of the proposed control strategy was experimentally verified using the same truss structure. The energy consumed by the proposed control strategy was only 0.8 times that of the conventional control strategy when achieving the same level of vibration suppression performance. The proposed control strategy reduces dependency on machine learning models and offers an improved energy-efficient strategy to control electronic switches.