Synthesis of Reference Signal in Adaptive Feedback Controller for Structure Vibration Suppression

Adaptive control has been known to be desirable to accommodate the system parameter variations and adapt to operational requirements in smart (intelligent) structures. Conventional feedforward controller requires both the reference sensor to measure the disturbance and the error sensor to measure the residual vibration; however, the reference sensor measurement may be impractical because the disturbance is often not known a priori in structural vibration. This study presents an adaptive feedback controller design in which the reference signal is synthesized by the error sensor measurement and the system dynamics identification, which is a prerequisite also in adaptive feedforward controller design. The infinite impulse response (IIR) adaptive filter for system identification and the finite impulse response (FIR) adaptive filter for feedback controller are implemented on digital signal processor for effective on-line vibration suppression. Experimental results show that the controller performance is strongly influenced by the accuracy of system identification. The controller achieves broadband attenuation and remains robust under parameter variations.