Integrated Design of Normal and Fault Modes for Spacecraft Control Systems

This paper proposes an integrated design method of normal and fault modes for spacecraft control systems. The proposed method can not only achieve sub-optimal performance for the fault-free system but also retain the desired performance through system reconfiguration despite the occurrence of actuator faults, striking a good balance between the nominal performance in the normal mode and system reconfigurability in fault modes. First, a reliable controller is designed to keep the system robustly stable against actuator faults with a performance bound. Then, the conservativeness of the controller is further reduced to improve the nominal performance since a system is expected to run for the longest time in the nominal modes. Finally, the effectiveness of the developed method is verified via an example of the spacecraft attitude control system.