采用压电开关分流电路技术的半主动振动控制

SEMI-ACTIVE VIBRATION CONTROL BY STATE-SWITCHED PIEZOELECTRIC SHUNT CIRCUIT

利用压电材料的正压电效应,设计出一种新型的状态开关型压电分流电路。由压电换能器将结构振动变形的应变能转化为电介能,当压电换能器极化表面的电荷积聚达到最大值时,闭合分流电路中的状态开关,分流电路短路,压电换能器上下表面的正负电荷中和抵消,以焦耳热的形式耗散掉电介能,达到抑制结构振动的目的。将这种振动控制技术应用于柔性悬臂梁的振动抑制,研究状态开关闭合持续时间对抑振效果的影响。实验结果表明,开关的闭合持续时间约为结构振动周期的1/10时,抑振效果最佳,悬臂梁第一阶稳态响应幅值降低量约为55%。

The piezoelectric state-switched shunt circuit technique is an emerged semi-active vibration control approach. In this approach, the two poles of the bonded piezoelectric transducer are switched from the open state to short state, which leads to two kinds of vibration suppression effects： variable equivalent stiffness and energy dissipation. A novel piezoelectric state-switched shunt circuit is proposed based on the piezoelectric effects. The state-switch is closed when the induced electric charge on the piezoelectric transducer reaches its maximum, and then the positive and negative charge are neutralized. In this process, the dissipated mechanical energy is composed of two parts. One part is the damping of higher mode vibration of the structure which is induced by variable stiffness effect, and this part is neglectable for the amount of the stiffness variation is very small. The other is the electric energy which is dissipated as joule heat in the circuit so as to suppress the structure vibration. The AC/DC（altemating current/direct current） rectifier and the MOS- FET （metal oxide semiconductor field effect transistor） are used in the shunt circuit to control the alternating current. The maximurn/minimum voltage detector is designed based on Simulink/dSPACE system which can generate the pulse signal to open the switch at the right time adaptively. The experiment is carried out to suppress the harmonic response of a cantilever beam. The vibration amplitude is reduced by a rate of 55 % after the control on. These vibration control results show the feasibility and the effectiveness of the state switched shunt circuit technique. Moreover, the effect of the pulse width is also studied in the experiments. It shows that the optimal pulse width is ten percent of the vibration period of the structure.