Weighted evenly peak reduction method for multimodal NC-piezoelectric shunt-damping

Abstract

Piezoelectric NC-shunt damping is a technique for vibration suppression by connecting an external circuit called the NC-shunt circuit (Negative capacitor shunt circuit) to a piezoelectric element attached to a mechanical structure. In this paper, we develop the multimodal NC-piezoelectric shunt-damping by proposing a new cost function, which enables to evaluate the decreases in multiple resonance peaks equally. The proposed method takes the difference between the gain peak when uncontrolled and the gain peak when the selected NC-shunt circuit is used. It then selects the smallest of the multiple vibration modes and optimizes it to be larger. Numerical examples are demonstrated to evaluate the effectiveness of the proposed cost function. In addition, we investigate the gain diagrams of the open-loop transfer functions to clarify the key issues in the broad-band vibration control performance of the NC-shunt circuit. It is shown that the vibration control is effective if the anti-resonance and resonance frequencies of the open-loop transfer function are located between the bending points of the admittance.