Model‐free fault‐tolerant control approach for uncertain state‐constrained linear systems with actuator faults

Abstract

This paper investigates the robust adaptive fault-tolerant control problem for state-constrained continuoustime linear systems with parameter uncertainties, external disturbances, and actuator faults including stuck, outage, and loss of effectiveness. It is assumed that the knowledge of the system matrices, as well as the upper bounds of the disturbances and faults, is unknown. By incorporating a barrier-function like term into the Lyapunov function design, a novel model-free fault-tolerant control scheme is proposed in a parameterdependent form, and the state constraint requirements are guaranteed. The time-varying parameters are adjusted online based on an adaptive method to prevent the states from violating the constraints and compensate automatically the uncertainties, disturbances, and actuator faults. The time-invariant parameters solved by using data-based policy iteration algorithm are introduced for helping to stabilize the system. Furthermore, it is shown that the states converge asymptotically to zero without transgression of the constraints and all signals in the resulting closed-loop system are uniformly bounded. Finally, two simulation examples are provided to show the effectiveness of the proposed approach.

Observer‐based attack‐resilient control for linear systems against FDI attacks on communication links from controller to actuators

“…Even though the existence of the constraints will make the attack‐resilient control problem more complicated than the one under consideration, the proposed control architecture still provides more or less the same line of thought to handle the problem. For example, taking account of state‐constrained linear systems, the barrier function–like term can be introduced to design the piecewise observer‐based controller such that the state constraint requirements can be guaranteed. Moreover, nonlinearity widely exists in many practical systems, such as flight control systems, power systems, economical systems, and biological systems.…”

Stabilisation of locally Lipschitz non‐linear systems under input saturation and quantisation

“…The present study can be further extended for considering the additional control constraints, like state‐constraints and actuator faults [37], unknown parameters [38], and overflow constraints on dynamic control systems [39–41], to enhance the scope of the proposed constrained control approach. In addition, further studies can be taken into account for obtaining the necessary and sufficient conditions for the solvability of the controller design constraints under input saturation and quantisation non‐linearities.…”

Adaptive output feedback fault‐tolerant control for MIMO non‐affine non‐linear systems based on disturbance observer

“…In this section, by utilising the backstepping control design technique, and combing the design method of the non‐linear disturbance observer, the fuzzy adaptive FTC design method [37] will be developed and the stability [38] of the controlled system will be proved.…”