Non-fragile Fault-tolerant Control Research Articles

Neural network-based direct robust adaptive non-fragile fault-tolerant control of amorphous flattened air-ground wireless self-assembly system

PurposeIn this paper, the authors take an amorphous flattened air-ground wireless self-assembling network system as the research object and focus on solving the wireless self-assembling network topology instability problem caused by unknown control communication faults during the operation of this system.Design/methodology/approachIn the paper, the authors propose a neural network-based direct robust adaptive non-fragile fault-tolerant control algorithm suitable for the air-ground integrated wireless ad hoc network integrated system.FindingsThe simulation results show that the system eventually tends to be asymptotically stable, and the estimation error asymptotically tends to zero with the feedback adjustment of the designed controller. The system as a whole has good fault tolerance performance and autonomous learning approximation performance. The experimental results show that the wireless self-assembled network topology has good stability performance and can change flexibly and adaptively with scene changes. The stability performance of the wireless self-assembled network topology is improved by 66.7% at maximum.Research limitations/implicationsThe research results may lack generalisability because of the chosen research approach. Therefore, researchers are encouraged to test the proposed propositions further.Originality/valueThis paper designs a direct, robust, non-fragile adaptive neural network fault-tolerant controller based on the Lyapunov stability principle and neural network learning capability. By directly optimizing the feedback matrix K to approximate the robust fault-tolerant correction factor, the neural network adaptive adjustment factor enables the system as a whole to resist unknown control and communication failures during operation, thus achieving the goal of stable wireless self-assembled network topology.

Robust Non-Fragile Fault Tolerant Control for Ensuring the Safety of the Intended Functionality of Cooperative Adaptive Cruise Control

Cooperative adaptive cruise control (CACC) has the potential to significantly improve road safety, highway throughput and reduce fuel consumption. However, the safety of the intended functionality (SOTIF) of CACC that focuses on unreasonable risks related to performance limitations has not been addressed. Moreover, various unknown uncertainties, disturbances, and controller perturbations present in the road environment make the guarantee of SOTIF for CACC a more challenging problem. This study presents a robust non-fragile fault tolerant control (RNFTC) strategy as a quantitative risk reduction method for ensuring SOTIF of CACC with system uncertainty, multisource disturbances, and controller perturbations. First, an intermediate based robust estimation method is proposed to estimate the performance limitations of perception and actuation, system states, and matched disturbances, simultaneously. Second, a robust non-fragile <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{H}_{\infty }$ </tex-math></inline-formula> FTC method is proposed to accommodate the simultaneous presence of performance limitations and disturbances. Third, theorems for solving optimal estimator and controller gains of the proposed RNFTC are derived in terms of linear matrix inequalities (LMIs). The requirements for CACC system stability, robustness, non-fragile and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{H}_{\infty }$ </tex-math></inline-formula> performances under the proposed RNFTC are analyzed using Lyapunov theory. Finally, a series of comparative simulations with the CACC system are conducted to demonstrate the effectiveness and superiority of the proposed RNFTC method on ensuring SOTIF of CACC under unknown uncertainties, disturbances, and perturbations.

Risk reduction for safety of the intended functionality of CACC with complex uncertainties: A cooperative robust non-fragile fault tolerant strategy

Safety of the intended functionality (SOTIF) of connected and autonomous vehicles (CAVs) is very challenging due to heterogeneous performance limitations and complex uncertainties in real road environments. In this paper, a cooperative robust non-fragile fault tolerant control (CRNFTC) strategy is presented to reduce the risks caused by multi-vehicle performance limitations of perception and actuation systems for ensuring SOTIF of cooperative adaptive cruise control (CACC). First, an intermediate based cooperative robust estimation method is proposed, by combining ego and cooperative information, system states, matched disturbances, performance limitations of perception and actuation of the vehicles in the platoon are simultaneously estimated. Existence conditions of estimators are given with respect to predecessor following (PF) and bi-directional (BD) communication network topologies. Then, based on the estimation, a distributed robust non-fragile fault tolerant H∞ control method is proposed, such that compensation of the effects of heterogeneous performance limitations and matched disturbances, and suppression of the remaining unmatched disturbances can be achieved. The sufficient condition and optimal solution of the proposed CRNFTC are obtained by using Lyapunov theory with explicit consideration of the system uncertainty and controller perturbation. The efficacy and superiority of the proposed CRNFTC for ensuring SOTIF of the CACC of PF and BD communication network topologies with complex uncertainties are substantiated via a series of simulations and quantitative comparisons.

Non-Fragile Fault-Tolerant Control Design for Fractional-Order Nonlinear Systems With Distributed Delays and Fractional Parametric Uncertainties

This work discuss the stabilization issue for a class of fractional-order nonlinear systems together with time delay, parametric uncertainties and actuator faults. Precisely, the considered system comprises of two delays namely distributed delay and time-varying delay. Moreover, the occurrence of the actuator faults and fractional parametric uncertainties may induce poor performance of the systems. To overcome these issue, a non-fragile fault-tolerant controller is designed which makes the system asymptotically stable with the specified mixed <inline-formula> <tex-math notation="LaTeX">$H_{\infty} $ </tex-math></inline-formula> and passive performance index. A fractional Razumikhin theorem is applied to handle the distributed delay term in the stabilization analysis. With the aid of suitable Lyapunov-Krasovskii functional, the sufficient conditions are established in terms of linear matrix inequalities together with Razumikhin stability theorem for getting the required results. By virtue of this, the controller gain matrix is obtained by solving the obtained LMIs and the graphical results are simulated using FOMCON toolbox. Later, the potency of the developed results are validated by virtue of three numerical examples including a rocket motor chamber.

Robust Simultaneous Fault Estimation and Nonfragile Output Feedback Fault-Tolerant Control for Markovian Jump Systems

This paper is devoted to solve the problems on simultaneous actuator and sensor fault estimations as well as the nonfragile fault-tolerant control (FTC) for a kind of Markovian jump systems with faults and disturbances. First, the considered system is converted to an augmented system by putting the sensor fault into the new state. Then, an adaptive observer is designed for the descriptor system with the actuator fault adjusted by the designed adaptive law. Based on the estimated actuator faults, an output-feedback-based FTC strategy is proposed to stabilize the closed-loop system against actuator and sensor faults, and disturbances, while showing robustness for the control gain perturbations. Sufficient conditions for the existences of the observer and controller are provided in forms of linear matrix inequalities. Finally, a practical application is given to express the validation and effectiveness of the proposed method.

Non-fragile fault-tolerant control for nonlinear Markovian jump systems with intermittent actuator fault

The non-fragile fault-tolerant control for a class of nonlinear Markovian jump systems with intermittent multiple actuator faults is addressed in this study. The nonlinearity in the considered system is assumed to satisfy sector constraint. Multiple Markov chains are introduced to model the multiple intermittent actuator faults, which is in a multiplicative form. To ensure the fault tolerance of the closed-loop system in the presence of potential controller perturbation, a new non-fragile fault-tolerant controller is designed, which can stabilize the resulting closed-loop system and further satisfy a prescribed performance index. After appropriately synthesizing the fault model that dominated by multiple Markov chains and the underlying nonlinear Markovian jump system, a set of sufficient conditions for the considered problem focusing on the controller design is derived with both known and partially known transition probabilities, where the controller can be determined via a convex optimization procedure. An example is given to illustrate the effectiveness of the proposed controller.

Integrated fault estimation and non‐fragile fault‐tolerant control design for uncertain Takagi–Sugeno fuzzy systems with actuator fault and sensor fault

This study proposes an integrated design of robust fault estimation and non-fragile fault-tolerant control for a class of Takagi–Sugeno fuzzy systems subjected to disturbances, actuator fault and sensor fault. A fuzzy adaptive observer is developed to achieve simultaneous estimations of actuator fault and sensor fault, based on which a new non-fragile output feedback fault-tolerant controller is constructed to compensate for the effects of the disturbances and faults. Moreover, the proposed fault-tolerant controller proves non-fragile, since it offers the ability to suppress the control gain perturbations. Simulation results are presented to illustrate the effectiveness of the proposed approach.

Nonfragile Fault-Tolerant Fuzzy Observer-Based Controller Design for Nonlinear Systems

The problem of actuator fault estimation and fault-tolerant control for a class of uncertain nonlinear systems using Takagi–Sugeno fuzzy models is investigated. A design procedure for nonfragile proportional-integral (PI) observer is proposed to estimate the states of the nonlinear system and reconstruct the abrupt (modeled as step-like faults) and incipient fault signals. Subsequently, a nonfragile fault-tolerant controller is constructed, which is informed by the PI observer. Sufficient conditions of the existence of the PI observer and the fault-tolerant controller are provided in the form of linear matrix inequalities. The proposed fault-tolerant control architecture is tested on two numerical examples.