Development of a Multifunctional Smart Board with Embedded Self-Sensing Piezoelectric Actuators

在对采用自传感作动器的压电单元为界的铝板进行模态分析的基础上，建立了系统的状态方程。利用H_∞设计了控制器。研究了微综合鲁棒控制理论，并进行了振动抑制仿真和实验。结果表明，第一模态的振动降低了15 dB。其次，针对嵌入式压电智能复合板的振动抑制问题，建立了基于FIR滤波器和LMS的自适应控制系统。这种控制方法的优点是不需要振动系统的数学模型，即使系统参数发生变化，也能始终保持最优状态。该控制系统不仅在第一模态的共振频率处，而且在1200 Hz以下的所有模态的共振频率处都成功地抑制了振动。在此基础上，采用自适应控制方法，结合智能板和嵌入式压电元件自适应控制，构建了噪声主动控制系统。由于自感压电执行器只能测量智能板的振动，因此构造了一个估计器，从压电元件的信号中估计噪声压力级。这种噪声控制系统的优点是它不需要麦克风，所以它可以更紧凑的尺寸。实验结果表明，在1200hz范围内的多个共振峰处，噪声都能得到有效抑制。

Based on the modal analysis of an aluminum plate bounded with piezoelectric elements that were used self-sensing actuators, the state equations of the system were established. A controller was designed using the H_∞. and μ synthesis robust control theory and both simulation and experiment of vibration suppression were carried. The results showed that the vibration of the first mode was reduced by 15 dB.Next a control system with self-sensing actuators and adaptive control approach, which is base on FIR filter and LMS was established for the vibration suppression of a smart composite board with embedded piezoelectric elements. The advantages of this kind of control are that it does not require the mathematical model of the vibration system and that it can always maintain the optimal state even when the parameters of the systems change. With the new control system, the vibration was successfully suppressed not only at the resonance frequency of the first mode, but also at the resonance frequency of all the modes under 1,200 Hz.Furthermore, an active noise control system was constructed using the adaptive control approach and the smart board and adaptive control with embedded piezoelectric elements. Since the self-sensing piezoelectric actuator can only measure the vibration of the smart board, an estimator was constructed to estimate the noise pressure level from the signals of the piezoelectric elements. The advantage of this noise control system is that it does need microphone so that it can be more compact in size. The experimental results show that the noise can be effectively suppressed at many resonance peaks under 1,200Hz.