Controller reconfiguration against reaction wheel failure based on predictive filters

Reaction wheels are main actuators of satellite attitude control systems. If a mechanical failure of one out of four reaction wheels occurs, it should be detected quickly and the controller need be reconfigured to restore three-axis control using healthy reaction wheels. To realize fault tolerant control, a predictive filter is applied to obtain information of states and faults. Considering the actual reaction torques on wheels as unknown inputs, they can be estimated by a predictive filter with states. Based on this algorithm wheel faults can be diagnosed. In this paper, a controller reconfiguration structure using a predictive filter is presented and the usefulness of this method is illustrated by a simulation to a three-axis stable attitude control system of a satellite