A HYBRID STRUCTURAL CONTROL APPROACH FOR NARROW-BAND AND IMPULSIVE DISTURBANCE REJECTION

A hybrid structural control architecture which combines feedback-based transient suppression and robust narrow-band disturbance compensation using adaptive filtering methods is introduced in this paper, A gener al formulation of the controller is introduced first, without regard t o specific feedback or adaptive feedforward algorithms, It is shown th at inclusion of a feedback loop around an adaptive feedforward path le ads to faster convergence times of the adaptive compensator, The impro ved convergence characteristics are shown to be quite important to the performance of the adaptive control in the presence of impulsive dist urbances. An important contribution of the proposed hybrid controller is the generation of an uncontrollable reference signal for the adapti ve filter via an estimate of the disturbance(s) from a Kalman filter, Analysis of the hybrid compensator demonstrates that the new control l aw functions as an adaptive feedback controller when the estimated dis turbance is used for the reference signal, Demonstrations of the hybri d control system are presented for a simply supported plate subject to a mixed transient and persistent, narrow-band disturbance, Numerical and experimental results are based on implementation of a discrete lin ear quadratic Gaussian regulator design for the feedback loop and the filtered-X least-mean-squares adaptive feedforward algorithm, The simu lation and test results confirm improved convergence properties, stabi lity, and performance robustness of disturbance compensation and reduc ed sensitivity of the adaptive filter to transient disturbances for th e hybrid implementation, The hybrid design has potential in improving active control effectiveness in industrial noise and vibration control problems characterized by mixed impulsive and persistent disturbances . (C) 1996 Institute of Noise Control Engineering.