Adaptive simultaneous precision positioning and vibration control of intelligent composite structures

This paper presents an adaptive control scheme for simultaneous precision positioning and vibration suppression of intelligent structures. First, the structure and materials system of an active composite panel with piezoelectric ceramic patches are introduced. An adaptive control scheme, which consists of an adaptive feedback and two adaptive feedforward controllers, is then proposed. The two adaptive feedforward controllers are responsible, one for precision positioning and the other for vibration suppression, and the adaptive feedback controller affects both precision positioning and vibration suppression. Two PID feedback controllers and the proposed adaptive control scheme are experimentally studied on the active composite panel under harmonic and random disturbances, demonstrating that (a) for the PID feedback control. the controller grains should be chosen carefully to make a tradeoff between position tracking and vibration suppression, and the positioning accuracy varies for different disturbances due to residual vibrations; and (b) for the proposed adaptive control scheme, the vibration is entirely suppressed and the positioning accuracy is consistently excellent no matter what kind of disturbance is encountered. the relative steady state error is 3%, and the controller can adjust its weights to adapt to the changes of the command and the external disturbances.