Observer based fault reconstruction for spacecraft under loss of actuator effectiveness

In this paper, an observer-based fault detection and isolation (FDI) method is developed to detect actuator faults of a spacecraft in the presence of external disturbances. By employing the iterative learning technique, the designed FDI uses the last step information from observer to estimate the current fault signal. Lyapunov analysis shows that the reconstructed signal can approximate the fault signal to any accuracy with fairly good performance by using the proposed FDI, and can be implemented online and in real time. Finally, the performance of the fault reconstruction scheme derived here is evaluated extensively through numerical simulations.