Event-triggered Fault-tolerant Control Research Articles

Simplified ADP-Based Distributed Event-Triggered Fault-Tolerant Control of Heterogeneous Nonlinear Multiagent Systems With Full-State Constraints

Simplified ADP-Based Distributed Event-Triggered Fault-Tolerant Control of Heterogeneous Nonlinear Multiagent Systems With Full-State Constraints

Distributed Data-Driven Event-Triggered Fault-Tolerant Control for a Connected Heterogeneous Vehicle Platoon With Sensor Faults

Distributed Data-Driven Event-Triggered Fault-Tolerant Control for a Connected Heterogeneous Vehicle Platoon With Sensor Faults

Decentralized Event-Triggered Fault-Tolerant Control for Switched Interconnected Nonlinear Systems With Input Saturation and Time-Varying Full-State Constraints

Decentralized Event-Triggered Fault-Tolerant Control for Switched Interconnected Nonlinear Systems With Input Saturation and Time-Varying Full-State Constraints

Decentralized Output-Feedback Adaptive Event-Triggered Control for Interconnected Nonlinear Delay Systems with Actuator Failures

This paper investigates decentralized adaptive event-triggered fault-tolerant control for interconnected nonlinear delay systems with actuator failures. The actuator failures suffered include loss of effectiveness and bias faults. A control scheme based on the K-filter is proposed, which effectively compensates for the effects of unknown actuator failures. A hyperbolic tangent function and neural network are introduced to approximate the unknown interconnection function and nonlinear delay function. By introducing the dynamic surface control method, the “explosion of complexity” issue is addressed. Furthermore, our proposed controller can ensure that all states of the corresponding closed-loop system are semi-globally uniformly ultimately bounded and that the tracking error can converge to a small neighborhood of zero. Meanwhile, Zeno behavior can be effectively avoided. Finally, the validity of the proposed control scheme is verified using a simulation example.

Distributed Event-Triggered Quantized Fault-Tolerant Control of Linear Multiagent Systems With External Disturbances and Parameter Uncertainties.

In this article, the issue of fault-tolerant leader-following consensus under a distributed dynamic event-triggered mechanism is addressed for linear multiagent systems (MASs) in the presence of unknown parameter uncertainties, external disturbances, and actuator faults, including loss of effectiveness and bias, in which the mechanism is with quantized state measurements. Due to the fact that information is transmitted via a bandwidth-limited communication network, a quantized control scheme with a uniform quantizer is introduced for leader-following consensus. In order to decrease the communication load and save the limited communication network resources, a distributed event-triggered mechanism is studied for leader-following consensus problem of linear MASs with quantized state measurements. In the presence of actuator faults, external disturbances, and unknown parameter uncertainties, an adaptive coupling gain for the controller is presented. Based on the Lyapunov function approach, the stability of the closed-loop system and the convergence of consensus errors are proved. Furthermore, the Zeno behavior is excluded for the triggering time sequences. Finally, simulation studies are given to verify the effectiveness of the proposed event-triggered fault-tolerant control scheme.

Relaxed Stabilization of Event-Triggered Interval Type-2 T–S Fuzzy Positive Systems With Stochastic Actuator Failure

This paper studies the membership-function-dependent (MFD) stability and positivity analysis of positive Interval Type-2 (IT2) Takagi-Sugeno (T-S) fuzzy fault-tolerant control systems under the event-triggered control framework. Considering the fact that parameter uncertainties may exist in nonlinear plants, the IT2 T-S fuzzy model as an effective mathematical tool is employed to approximately express a complex positive system with nonlinearities and uncertainties. In order to save communication resources and improve the security of system operation, an event-triggered fault-tolerant control strategy is then designed based on the Imperfectly Premise Matching (IPM) concept. In addition, for capturing positivity characteristic and matching with the linear co-positive Lyapunov function, a novel event-triggered condition in the 1-norm rather than in the 2-norm is developed to control the positive IT2 T-S fuzzy systems. Thereinto, the non-convex problem as the first obstacle is required to be cleared since feasible solutions usually cannot be obtained based on the non-convex conditions. For dealing with this problem, a valid approach is presented to conduct convexification with the help of a user-chosen constant vector. Besides, because of event-triggered action, the inherent mismatched issue of the premise variables of the fuzzy model and the ones of the fuzzy controller is encountered. Fortunately, the advanced MFD analysis, which is capable of bringing the information contained in the membership functions (MFs) into the stability and positivity conditions, provides an effective strategy to remove this barrier. Consequently, relaxed results which can accomplish the stability and positivity for wider positive systems are developed and displayed in sum-of-squares (SOS) form. Detailed simulation results are given to clarify the effectiveness of the designed event-triggered fault-tolerant control method.

Adaptive event-triggered fault-tolerant control for Markov jump nonlinear systems with time-varying delays and multiple faults

In this paper, a state feedback H∞ controller is developed to solve the fault-tolerant (FT) control problem of a class of discrete-time networked Markov jump nonlinear systems (MJNSs), which are affected by time-varying delays, external disturbances, actuator and sensor faults, and network-induced time delays, simultaneously. The mode-dependent adaptive event-triggered mechanism is introduced to capture as many valid features of the desired signal as possible while maximizing network resource savings. Then, based on the Lyapunov–Krasovskii (L–K) theory, sufficient conditions for the closed-loop system to be stochastically stable and to satisfy a specified H∞ performance index are obtained. Based on the above, the design methods of the FT controller are given in the form of linear matrix inequalities (LMIs). Finally, the effectiveness of the designed FT controller is verified by an example simulation.

Disturbance observer-based event-triggered fault tolerant control for coupled spacecraft on SE(3) with actuator saturation and misalignment

Disturbance observer-based event-triggered fault tolerant control for coupled spacecraft on SE(3) with actuator saturation and misalignment

Prescribed performance event-triggered fault-tolerant control of uncertain pure-feedback nonlinear systems

The prescribed performance event-triggered fault-tolerant control (FTC) problem is considered for a class of uncertain pure-feedback nonlinear systems with actuator failures. Contrary to the existing results, the novel decoupling condition and the universal construction mode of error transformation are first given. Based on this, a new radical constrained function is used to low-complexity controller design without involving the Nussbaum gain scheme or adaptation parameter updated structure, in spite of nonlinear coupling and event triggering input. It is proved that the desired prescribed accuracy of the closed-loop output tracking can be achieved and the number of event-trigger showed a significant reduction. The effectiveness of theory results is verified by simulation on a numerical example.

Event-triggered fault-tolerant control for input-constrained nonlinear systems with mismatched disturbances via adaptive dynamic programming

In this paper, the issue of event-triggered optimal fault-tolerant control is investigated for input-constrained nonlinear systems with mismatched disturbances. To eliminate the effect of abrupt faults and ensure the optimal performance of general nonlinear dynamics, an adaptive dynamic programming (ADP) algorithm is employed to develop a sliding mode fault-tolerant control strategy. When the system trajectories converge to the sliding-mode surface, the equivalent sliding mode dynamics is transformed into a reformulated auxiliary system with a modified cost function. Then, a single critic neural network (NN) is adopted to solve the modified Hamilton–Jacobi–Bellman (HJB) equation. In order to overcome the difficulty that arises from the persistence of excitation (PE) condition, the experience replay technique is utilized to update the critic weights. In this study, a novel control method is proposed, which can effectively eliminate the effects of abrupt faults while achieving optimal control with the minimum cost under a single network architecture. Furthermore, the closed-loop nonlinear system is proved to be uniformly ultimate boundedness based on Lyapunov stability theory. Finally, three examples are presented to verify the validity of the control strategy.

Discrete Event-Triggered Fault-Tolerant Control of Underwater Vehicles Based on Takagi–Sugeno Fuzzy Model

This article investigates the fault estimation and fault-tolerant control problem for underwater vehicles with the Takagi–Sugeno (T–S) fuzzy model. In order to deal with the disturbance of complex ocean environment, a stable fuzzy controller for underwater vehicle is proposed to realize efficient operation, which is on the basis of T–S fuzzy model with pitch angle membership function. Meanwhile, to reduce the waste of communication resources, a novel discrete event-triggered control scheme is proposed to use multiple historical sampled data to determine the next release instant. The discrete event-triggered fault-tolerant controller compensates for the influence of system faults by using state estimators and fault estimators. It is noted that the canonical Bessel–Legendre inequality and delay-dependent canonical orthogonal Legendre polynomials play an important role in dealing with the asymptotical stability of the T–S fuzzy delayed model with an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H_{\infty }$ </tex-math></inline-formula> performance. Finally, a simulation example is carried out to show the validity of the presented theorem.

Analysis and design of control systems via parameter‐based approach

Analysis and design of control systems via parameter‐based approach

Adaptive event-triggered fault-tolerant consensus of linear heterogeneous multiagent systems via hierarchical approach

This article investigates the event-triggered fault-tolerant consensus problem for heterogeneous linear multiagent systems (MASs) with actuator failures. By introducing the hierarchical control scheme, a distributed adaptive event-triggered fault-tolerant control method is proposed. The upper layer and the lower layer comprise the hierarchical control structure. The upper layer is made up of a virtual reference system and a distributed cooperative controller with event-triggered mechanism, while the lower layer is composed of an actual system and a fault-tolerant tracking controller. The main contribution of this work is that the phenomena of fault propagation could be prevented employing presented control method when compared to the most commonly used distributed fault-tolerant control methods. And continuous transmission between agents can be eliminated due to the event-triggered mechanism. It is shown that the consensus error converges to zero asymptotically. Finally, the effectiveness of the theoretical result is illustrated by a simulation example.

Adaptive neural network projection analytical fault-tolerant control of underwater salvage robot with event trigger.

To solve the problem of control failure caused by system failure of deep-water salvage equipment under severe sea conditions, an event-triggered fault-tolerant control method (PEFC) based on proportional logarithmic projection analysis is proposed innovatively. First, taking the claw-type underwater salvage robot as the research object, amore universal thruster fault model was established to describe the fault state of equipment failure, interruption, stuck, and poor contact. Second, the controller was designed by the proportional logarithmic projection analytical method. The system input signal was amplified and projected as a virtual input, which replaces the original input to isolate and learn the fault factor online by the analytical algorithm. The terminal sliding mode observer was used to compensate for the external disturbance of the system, and the adaptive neural network was used to fit the dynamic uncertainty of the system. The system input was introduced into the event-triggered mechanism to reduce the output regulation frequency of the fault thruster. Finally, the simulation results showed that the method adopted in this study reduced the power output by 28.95% and the update frequency of power output by 75% compared with the traditional adaptive overdrive fault-tolerant control (AOFC) method and realized accurate pose tracking under external disturbance and system dynamic uncertain disturbance. It has been proven that the algorithm used in this research can still reasonably allocate power to reduce the load of a fault thruster and complete the tracking task under fault conditions.

Decentralized Event-Triggered Adaptive Control for Interconnected Nonlinear Systems With Actuator Failures

In this article, the problem of decentralized event-triggered fault-tolerant control (FTC) for a class of interconnected nonlinear systems with unknown strong coupling and actuator failures is considered. In order to enable each subsystem output to track the desired trajectory, a new decentralized adaptive control scheme is given. First, an event-triggering mechanism is introduced to reduce the signal transmission frequency between the controller and the actuator. Second, a fuzzy high-gain observer is designed for each subsystem to estimate unknown nonlinear functions and actuator efficiency factor. Third, a decentralized FTC strategy is proposed to compensate for the effects of actuator failures and achieve the desirable system tracking performance. With the aid of graph theory, it is shown that all the closed-loop signals are semiglobally uniformly ultimately bounded, and the tracking error of each subsystem can converge to an arbitrarily small residual set by adjusting a design parameter. The effectiveness of the proposed scheme is demonstrated by a practical interconnected system.

Event-Triggered Fault-Tolerant Control for Nonlinear Networked Control Systems

This paper addresses the communication congestion and actuator fault in a nonlinear networked control system. A weighted average event-triggered mechanism adopted the weighted average of data packets is proposed to alleviate the communication congestion and save the network communication resources. Meanwhile, based on the system state estimation and fault estimation obtained by a state-fault observer, a fault-tolerant controller is designed to compensate and reduce the influence of fault and nonlinear factors in the networked control systems. The stability of the closed-loop system is proved by the Lyapunov–Kroasovskii theory, and the gains of the observer and controller are obtained by linear matrix inequalities. The feasibility of the proposed scheme is verified by the networked motor control system. The proposed weighted average event-triggered fault-tolerant control scheme can reduce the data transmission without affecting system performance. Meanwhile, it not only has fault-tolerant control performance but also reduces the influence of nonlinear factors on the system output.

Event-Triggered Attitude-Orbit Coupled Fault-Tolerant Control for Multi-Spacecraft Formation

In this paper, the attitude-orbit coupled control problem for multi-spacecraft formation with limited communication capability and actuator failure is investigated. For the purpose of solving this problem, an event-triggered attitude-orbit coupled fault-tolerant control strategy is proposed. First, an integrated nonlinear dynamic model including the coupling characteristics of the attitude and orbit is established based on the Kane equation. Second, the nonlinear dynamic model is linearized at the reference state to facilitate the controller design. Third, a dynamic event-triggered mechanism is designed and an event-triggered fault-tolerant control law is developed. The stability of closed-loop control systems can be ensured under the designed control law and a sufficient condition that Zeno’s behavior can be avoided is presented. Finally, simulation results are given to show the effectiveness of the proposed control method.

Attitude tracking control for fractionated spacecraft with actuator failures under adaptive event-triggered strategy

In this paper, two event-triggered algorithms are investigated to reduce the consumption and occupation of system resources for attitude tracking control of spacecraft system under external disturbances, model uncertainties, actuator failures, and limited communication. The first robust controller is designed with the triggering condition based on a time-based exponential function that has a dynamically decreasing trigger threshold. To improve the first controller, the second controller with the adaptive triggering condition based on a time-based exponential function is established to facilitate the realization of a comprehensive combination of feedback compensation mechanism and event-triggered control theory. It follows from the theoretical analysis that asymptotic convergence and Zeno-free are achieved under the proposed controller. Simulation results are provided to verify the effectiveness of the developed adaptive event-triggered fault-tolerant control laws.

Robust adaptive event-triggered fault-tolerant control for time-varying systems against perturbations and faulty actuators

In this paper, the robust adaptive event-triggered fault-tolerant control (FTC) problem is addressed for a time-varying continuous-time system with perturbations and general actuator failures. In order to eliminate the adverse effects of faults and perturbations on system performance, a robust fault-tolerant controller is derived via integrating direct adaptive control technique to adjust control parameters. For the sake of reducing the communication resources and actuator actions, an event-triggered control technique is presented to adjust the control inputs based on the proposed FTC strategy. To ensure the system is free from Zeno phenomenon, a bound on the inter-event execution time is established. On the basis of the event-trigger condition, the uniformly bounded stability results of the adaptive FTC system are obtained by utilizing Lyapunov stability theory in the presence of actuator failures and perturbations. The superior of the developed control strategy is substantiated by simulation results of a rocket fairing system.

Finite-time event-triggered fault-tolerant control for a family of pure-feedback systems

This article focuses on the event-triggered fault-tolerant control (ETFTC) for a family of nonlinear pure-feedback systems (PFSs) is investigated. Firstly, the differential mean-value theorem (MVT) is applicable to deal with the nonaffine function in systems and the control input signals were successfully decoupled. Then, by using backstepping technique and the fuzzy logic systems (FLSs), a novel finite-time ETFTC scheme is effectively rendered. Furthermore, the newly designed fault-tolerant controller compensates for actuator faults, the trigger mechanism improves the transmission efficiency of the input signals, and the ETFTC scheme guarantees that all closed-loop signals are bounded. Comparative simulation results further validate the effectiveness of the given control method.