Adaptive multi-modal vibration control of wing-like composite structure using adaptive positive position feedback

An on-line estimation method of natural frequencies and an adaptive controller, Adaptive Positive Position Feedback (APPF), are proposed for the multi-modal vibration control. Spillover phenomena and real-time system identification have been obviously difficult problems for the multimodal adaptive vibration control. To overcome these problems, we propose a fast and powerful algorithm for the frequency identification of time-varying structures. Variable PPF controllers are adjusted with estimated natural frequencies at every time step. An experimental model of wing-like composite plate with a bonded piezoelectric sensor and an actuator was prepared. The natural frequencies of the model are changed by attached masses. The experimental results show that natural frequencies are estimated quite accurately and that the vibration of controlled modes Is reduced very much. On the contrary, the performance of the conventional LQG controller is significantly degraded due to frequency variations.