Image Stabilization of a Model-Following Dual-Stage System With Charge-Coupled Device Measurement

Abstract

This article develops a charge couple device (CCD)based dual-stage system consisting of cubic Stewart platform and tip-tilt mirror to stabilize the line-of-sight (LOS) for space optical payloads. Due to the conventional offloading strategy needing the accurate characteristic of the CCD and additional position sensor in terms of precision and bandwidth, a novel model-following offloading strategy is presented to achieve the offloading for the dual-stage system. The essence of the proposed strategy is that the following position signal can be estimated through combining the controller output with the model-based estimation of the tiptilt mirror to be offloaded into the Stewart platform. Besides, an error-based observation control technique is introduced to relax the limitations imposed by the low sampling rate of the CCD on closed-loop performance for the tip-tilt mirror loop. This technique reduces reliance on the precise control model and optimizes the tracking performance by the design of an appropriate Q-filter. The simulations and experiments of the dual-stage image stabilization system demonstrate the validity of the presented approach.