Adaptive Parallel Control for Wideband Multi-Frequency Vibration Rejection: Design and Application to A Piezoelectric Tip-tilt Stage

Image-stabilized piezoelectric tip-tilt stages are subjected to various external disturbances. Traditional disturbance rejection methods primarily focus on narrow-band disturbances, neglecting the impact of wideband disturbances characterized by energy concentration across multiple frequency bands, which can significantly degrade stabilization accuracy. These wideband disturbances are typically time-varying, with wide spectral peaks appearing at frequencies above the servo bandwidth. To address the challenge of mitigating such disturbances, this paper proposes an adaptive parallel control method. The adaptive strategy enables two-degree-of-freedom estimation of the disturbance's central frequency and spectral peak width, allowing for automatic adjustment of control efforts based on real-time disturbance characteristics. Based on the estimated disturbance features, a reduced-order parallel control strategy is designed to accommodate the presence of multiple wideband disturbances. The proposed control strategy was evaluated on a piezoelectric tip-tilt imaging system. Results demonstrate that the method effectively suppresses multiple wideband disturbances.