An adaptive active vibration control for flexible beam systems under unknown deterministic disturbances

Abstract

An adaptive active vibration control approach has been proposed for flexible beam systems to reject unknown deterministic disturbance in this paper. In the proposed feedback control scheme, a robust controller is firstly developed to stabilize the mode-truncated inner-loop system with the properly formulated uncertain transfer functions. Subsequently, the Youla parameters are augmented with the base robust controller to formulate a Q parametrized set of all stabilizing controllers, whose dimensionality of Q is suitably selected to meet the requirement pertaining to the robustness in the context of model uncertainties of the flexible beam system and the disturbance characteristics. A recursive least squares (RLS) algorithm incorporating projection is utilized to adjust the augmented Youla parameters online for the disturbance with the unknown and time-varying characteristics. The existence of Youla parameters and the stability of the proposed Youla adaptive vibration control scheme have been analyzed. The simulation for a flexible beam system against unknown deterministic disturbance and an experimental test evaluation to attenuate the unknown flying height fluctuations of the read/write head suspension in data storage system have been illustrated to show the effectiveness of the proposed adaptive active vibration control approach.