Fault Tolerant Control Design for The Attitude Control Systems of Flexible Spacecraft with Sensor Faults

This paper presents a fault compensation-based fault tolerant control scheme for the attitude control systems of flexible spacecraft with sensor faults using descriptor observer technique. Firstly, the flexible spacecraft attitude dynamics model is introduced, and a healthy dynamic output feedback controller is also given. When some unknown sensor faults occurred, to achieve the estimation value of unknown faults, the faulty attitude control systems of flexible spacecraft are transformed into the augment descriptor systems, and then a descriptor observer is developed to obtain the accurate estimation value of sensor faults. Based on Lyapunov approach, the descriptor observer unknown gain matrix is characterized in terms of the solution to a linear matrix inequality, which can be readily solved using standard software packages. Next, the compensation-scheme-based fault tolerant controller is presented for the faulty attitude control systems of flexible spacecraft by using the obtained the sensor fault estimation information. Finally, simulation results are given to demonstrate the effectiveness of the proposed approach.