Energy Regenerative Active Vibration Control of Cantilever Beam Using Piezoelectric Actuator and Class D Amplifier

Abstract

Active vibration control usually reduces vibration amplitude and mechanical energy of vibrating structures. In the situation, actuators of active vibration control systems must remove energy from vibrating structures. However, the consideration is inconsistent with a common knowledge of active vibration control, active vibration control systems need external power supply to drive actuators. To find an answer to the inconsistency, a power flow in an active vibration control system of a SDOF oscillator using a piezoelectric actuator has been investigated by the authors analytically. The reason for using the piezoelectric actuator is that piezoelectric actuators have little internal loss and the characteristics make easy to understand essentials of power flows in active vibration control systems. The investigation shows that the actuator is not consuming power from external source but removing and regenerating energy from the SDOF oscillator. The power consumption of the system is caused by the energy loss of the amplifier to drive the actuator. The result implies that an energy regenerative active vibration control method can be realized by reducing energy losses of amplifiers. The energy losses can be reduced by using class D amplifiers, high efficient amplifiers based on switching operation of semiconductor devices, instead of conventional linear amplifiers. The validity of the approach is shown by a numerical simulation. An advantage of the proposed method compared to other energy regenerative vibration control methods and semi-active methods is that the proposed method can use any controllers for ordinary active vibration control and can achieve the same control performance because the difference between ordinary active vibration control methods and the proposed method is only type of amplifier. In this paper, the validity and the advantage are confirmed by experimental comparisons of power flows and control performance of two active vibration control systems using a conventional linear amplifier and a class D amplifier with the same controller and the same actuator.