Multi-modal vibration control using amended disturbance observer compensation

Piezoelectric panel is a fundamental element in many structures characterised with multi-variables, coupling and uncertain external excitation. Many advanced active control schemes have been reported for the multi-modal of piezoelectric structure. However, these control schemes, including the multi-loop PID method usually cannot achieve satisfying performance in the presence of strong external disturbances and coupling effects. To this end, an amended disturbance observer (DOB) based on multi-loop PID scheme is developed to control a two-mode piezoelectric panel. The system considered here is with lumped disturbances including external disturbances, such as the variations of the output of the modal and the external excitation, and internal disturbances, such as coupling effects. The proposed control approach consists of two compound controllers, and each controller includes a PID feedback part and a feed-forward compensation part based on DOB for disturbances. In order to obtain a better vibration suppressing performance, a chaos optimisation method based on Logistic map and a new transient performance function is designed to tune the parameters of PID controller. A rigorous analysis is also given to show why the DOB can effectively suppress the variations. At last, in order to verify the proposed algorithm, the dSPACE real-time simulation platform is used and an experimental platform for the all-clamped stiffened panel structure active vibration control is set up. The simulation and experiment results demonstrate that the proposed method has a much better vibration suppressing property with almost the same input voltage than the multi-loop PID method in the piezoelectric panel.