Composite Active Disturbance Rejection Vibration Isolation Control Based on Compensation for Unknown Disturbance

Abstract

Active vibration isolation is widely recognized as an effective approach for suppressing low-frequency vibrations. Linear active disturbance rejection control (LADRC) serves as a powerful strategy for active vibration isolation. However, classic LADRC depends on displacement sensors, which are often bulky and prone to measurement instability. Substituting accelerometers for displacement sensors offers a promising alternative, as the former are generally more compact and provide superior measurement stability. Nevertheless, the integration of accelerometers into classic LADRC requires double integration to derive displacement, leading to low-frequency drift that may drive the system out of control. To overcome such limitation, this paper proposes a composite ADRC algorithm with a collaborative disturbance observer (CDO). The CDO integrates reduced-order LESO (RLESO) and Kalman filter (KF) in a complementary manner, which directly uses acceleration as input to avoid the risk of integral drift and realizes the functional complementarity between KF in state reconstruction and RLESO in disturbance estimation. Moreover, a composite scheme combining known-disturbance feedforward, unknown-disturbance feedback, and state errors feedback is adopted. Theory and experiments show that this method can achieve effective state reconstruction and disturbance suppression with only accelerometers while exhibiting good tolerance to small control-loop time delays, providing a streamlined and efficient solution for low-frequency broadband vibration isolation.