Fault-Tolerant Control of UAV Anti-Skid Braking System with Output Constraint

This paper develops a sliding mode observer-based fault-tolerant control method for actuator fault in UAV anti-skid braking system. The braking system is modeled in presence of nonlinear bias fault and external unknown disturbance. A sliding-mode observer is employed, meanwhile, the fault reconstruction law is designed by means of sliding-mode equivalent control methodology. A novel fault-tolerant control method of barrier Lyapunov function backstepping control, based on fault reconfiguration information is proposed for preventing output from violating the constraint. Furthermore, the adaptive disturbance estimator is designed to achieve unknown external disturbance rejection. It is proved that the cloosed loop system is semiglobally uniformly bounded using Lyapunov theory. Finally, simulation results are provided to show the effectiveness of the proposed approach.