L1 Adaptive for Aircraft Lateral Fault Tolerant Control with Actuator Failure

When aircraft is laterally controlled, actuator failure may cause matched/unmatched uncertainties. In order to deal with the uncertainty, a fault-tolerant controller is designed by using L1 adaptive control method. An aircraft lateral model was established by considering faults and disturbances, the effects of the uncertainty and interference were counteracted by using L1 adaptive controller in order to ensure the rapid adaptation and robustness, and then the stability and transient performance of the closed-loop system were proven through Lyapunov method. In the case of multiplicative fault, additive fault and stuck fault, the uncertainties of model parameter were added to simulate simultaneously. Simulation results showed that the present control method in both single-fault mode and hybrid-failure mode could ensure the uniform bounded control signal and parameter estimation, effectively eliminates the effect of the faults and had the good fault tolerance and robustness.

Distributed fault tolerant consensus control for multi-agent system with actuator fault based on adaptive observer

This paper mainly investigates the consensus control problem of multi-agent system with actuator fault under the leader-follower topology structure. For actuator fault, the additive and multiplicative fault are also considered in this paper. It is worth noting here that for actuator fault we only consider follower agent. For other factors that can affect system functionality, the external bounded disturbance and nonlinear factor are considered for all agents. The main paper organization structure is as follows. Firstly, by constructing nonlinear adaptive fault observer, the estimated values of actuator multiplicative fault and the unknown upper bound of actuator additive fault are respectively obtained. Subsequently, based on the estimated value of fault observer, a distributed fault-tolerant consensus control protocol is proposed to solve the consensus implementation problem of multi-agent system in the case of actuator fault. Finally, the effectiveness of fault-tolerant consensus control algorithm is proved by a simulation example of multi-aircraft system.

Multiplicative Fault Estimation-Based Adaptive Sliding Mode Fault-Tolerant Control Design for Nonlinear Systems

This article deals with the sliding mode fault-tolerant control (FTC) problem for a nonlinear system described under Takagi-Sugeno (T-S) fuzzy representation. In particular, the nonlinear system is corrupted with multiplicative actuator faults, process faults, and uncertainties. We start by constructing the separated FTC design to ensure robust stability of the closed-loop nonlinear system. First, we propose to conceive an adaptive observer in order to estimate nonlinear system states, as well as robust multiplicative fault estimation. The novelty of the proposed approach is that the observer gains are obtained by solving the multiobjective linear matrix inequality (LMI) optimization problem. Second, an adaptive sliding mode controller is suggested to offer a solution to stabilize the closed-loop system despite the occurrence of real fault effects. Compared with the separated FTC, this paper provides an integrated sliding mode FTC in order to achieve an optimal robustness interaction between observer and controller models. Thus, in a single-step LMI formulation, sufficient conditions are developed with multiobjective optimization performances to guarantee the stability of the closed-loop system. At last, nonlinear simulation results are given to illustrate the effectiveness of the proposed FTC to treat multiplicative faults.

Active fault-tolerant satellite attitude control based on fault effect classification

An active fault-tolerant satellite attitude control scheme based on fault effect classification is presented at the occurrence of faults associated with torques. In this paper, the flexibility and practicability of the fault-tolerant scheme are top priorities. Faults are modeled and divided into additive and multiplicative ones in order to estimate and deal with them specifically and exactly. The additive faults, including additive part of flywheel faults and other uncertain fault torques, are estimated by additive fault estimator and compensated on the basis of nominal controller, whereas the multiplicative faults, denoting torque gain parameter faults of flywheels, are estimated by multiplicative fault estimator and the estimated fault parameters are used for dynamic torque command distribution of flywheels. The final simulation examples and performance comparison of three fault-tolerant schemes show that the proposed scheme based on fault effect classification is an effective, flexible and saving-energy fault-tolerant satellite attitude control scheme. It possesses an engineering value for improving reliability and prolonging on-orbit working lifetime of satellites.