Evaluation of Semi-Active Control using Harmonically Varying Damping by Real-Time Hybrid Simulation

Abstract

This study demonstrates the efficiency of a new semi-active vibration control method validated using real-time hybrid simulation considering a single-degree-of-freedom system. The semi-active control method treated in this study is based on harmonically varying damping. Even if the input to the system doesn't contain the natural frequency of the system, it is possible to choose the frequency of the damping coefficient so that the response includes the natural frequency. As a result of this operation, resonance can be induced, with the phase and amplitude of the resonance adjustable through the damping parameters. Previous study proposed a new vibration control method to take advantage of harmonically varying damping. In the case that the excitation contains the natural frequency of the system, resonance is induced. At the same time, if the additional harmonic vibration induced by the variable damping is at the same frequency of the resonance yet anti-phase, the resonance can be reduced by interference. An expression for the variable damping controller has been developed in the case of an ideal variable damping device and control performance has been confirmed by numerical simulation. However, the control method does not directly apply to actual variable damping devices, because the control laws determine the ideal variable damping ratio, neglecting any nonlinearities of actual damping devices. In this study, the proposed theory has been modified to fit a magneto-rheological (MR) damper. Validation of the modification was performed experimentally using real-time hybrid simulation.