Resilient Anti-disturbance Dynamic Surface Control of Uncertain Strict-feedback Systems Subject to Partial Loss of Actuator Effectiveness

This paper is concerned with the tracking control of a class of uncertain strict-feedback systems subject to partial loss of actuator effectiveness, in addition to uncertain model dynamics and unknown disturbances. A resilient anti-disturbance dynamic surface control method is proposed to achieve stable tracking regardless of partial actuator faults. First, data-driven adaptive extended state observers are designed based on memory-based identifiers, such that the uncertain model dynamics, external disturbances, and the unknown input gains due to actuator faults can be estimated. Next, a resilient anti-disturbance dynamic surface controller is developed based on recovered information from the data-driven adaptive extended state observers. After that, it is proven that the cascade system formed by the observer and controller is input-to-state stable. Finally, comparative studies are performed to validate the efficacy of the resilient anti-disturbance dynamic surface control method for nonlinear strict-feedback systems subject to partial loss of actuator effectiveness.

L1 Adaptive Loss Fault Tolerance Control of Unmanned Hypersonic Aircraft with Elasticity

This paper investigates the fault tolerance control of hypersonic aircrafts with L1 adaptive control method in the presence of loss of actuator effectiveness fault. The hypersonic model considers the uncertainties caused by the features of nonlinearities and couplings. Elasticity is taken into account in hypersonic vehicle modeling which makes the model more accurate. A velocity L1 adaptive controller and an altitude L1 adaptive controller are designed to control flexible hypersonic vehicle model with actuator loss fault. A PID controller is designed as well for comparison. Finally, the simulation results are used to analyze the effectiveness of the controller. Compared to the results of PID controller, L1 controllers have better performance.

Fixed-Time Fault-Tolerant Attitude Tracking Control for Rigid Spacecraft

This paper addresses the fixed-time attitude tracking problem of rigid spacecraft with inertial uncertainties, external disturbances, and partial loss of actuator effectiveness faults. A new fixed-time terminal sliding surface is proposed and a singularity-free fixed-time fault-tolerant sliding mode control (FTSMC) is designed. It is proved that the proposed FTSMC can ensure that the attitude tracking errors converge to an arbitrary small bound centered on the equilibrium point within fixed time and then go to the equilibrium point asymptotically. The appealing features of the proposed control are fixed-time tracking stability featuring fast convergence, high precision, and strong robustness. Simulations verify the effectiveness of the proposed approach.