Research On Robust Fault Tolerant Control Method For Rigid Satellite Attitude Control System

In this paper,the rigid satellite attitude control system is taken as the research object.Aiming at the defects and deficiencies of the fault-tolerant control methods of the modern spacecraft actuators and sensors,based on the existing research results,the modern spacecraft is fully considered when performing space missions.In the case of external interference and inertial uncertainty encountered,new methods for fault diagnosis and fault-tolerant control of modern spacecraft attitude control system actuators and sensors are studied,so as to improve the spacecraft's autonomous operation capability and better implement transaction give them space missions.The main contributions of this paper are as follows(1)A new integrated fault-tolerant control strategy for rigid satellites in the presence of Lipschitz nonlinearity and sensor failure is proposed.In this paper,a robust sliding mode fault estimation observer is designed for satellite attitude systems,which can be used to estimate sensor faults.First,the sliding mode term is introduced to deal with the nonlinear uncertainty part of the system to make it robust.On this basis,combined with inversion control and fractional-order non-singular terminal sliding mode control technology,an integrated fault-tolerant control method is developed for the satellite attitude system under sensor failure,which makes the closed-loop system not only robust,but also better fault-tolerant for unknown sensor failures(2)Address the stabilization problem for the attitude systems of a rigid satellite with sensor faults and external disturbance.Firstly,a slide-mode observer is designed for the faulty attitude systems of rigid satellite in order to estimate the unknown sensor fault.Moreover,a discontinuous input is given to reduce the impact of sensor faults and aggregated uncertainties.Then,output feedback fault tolerant stabilization control scheme is proposed by using the estimated fault information to ensure the asymptotic stability of the faulty system(3)The problem of integrated fault-tolerant stabilization control is studied for the attitude systems of a rigid satellite with both actuator and sensor faults.Firstly,a virtual observer is designed for the faulty attitude systems of rigid satellite in order to estimate the unknown actuator and sensor faults.Because the virtual observer includes unmeasurable information of the attitude systems,the real observer is then presented.On this basis,an integrated sliding-mode fault-tolerant stabilization control approach is proposed by using the estimated fault information,and it not only suppresses the disturbance with a disturbance attenuation level?,but also eliminates the effects of actuator and sensor faults.Finally,the effectiveness of the proposed scheme is verified by numerical simulation.