Uncertain multiple jitters control of MEMS fast steering mirror at high frequencies

The line-of-sight (LOS) jitters caused by satellite platform vibrations significantly degrade the pointing stability of the optical axis, thereby reducing payload pointing performance. In the acquisition, pointing, and tracking (APT) system, low-frequency jitters has been well suppressed by the coarse tracking assembly, while high-frequency LOS jitters rely on the fine tracking assembly represented by the fast steering mirror (FSM). The FSM, based on the micro-electro-mechanical system (MEMS), exhibits the advantage of high bandwidth and is increasingly applied in APT systems to suppress high-frequency jitters. However, due to the complex dynamic characteristics of satellite platform vibrations, high-frequency jitters are typically multiple and uncertain, which makes it challenging to design the controller. To address this issue, this paper proposes a hybrid controller with frequency estimation. The hybrid controller is integrated with a PI controller and a parallel Filtered-x Least Mean Square (FxLMS) controller. The PI controller is employed to compensate the installation error in MEMS FSM, while the parallel FxLMS controller is employed to suppress high-frequency jitters. To autonomously estimate uncertain jitter frequency, a frequency estimation method based on the improved artificial bee colony (ABC) algorithm is proposed. The frequency estimation method combines the frequency-tracking capability of adaptive notch filter with the optimization mechanism of the ABC algorithm, ensuring the autonomous generation of available reference signals for the parallel FxLMS controller. The effectiveness of the proposed hybrid controller is validated through simulations and experiments. The proposed hybrid controller has been shown to effectively suppress jitters and remains effective even when the jitter frequency changes, demonstrating its potential as a solution for MEMS FSM with multiple uncertain jitters at high frequencies.