Abrupt Actuator Faults Research Articles

Membership functions dependent adaptive sliding mode fault‐tolerant control for uncertain T–S fuzzy systems with performance bounds

SummaryThis article is concerned with the problem of adaptive sliding mode control for uncertain Takagi–Sugeno fuzzy systems in the presence of actuator faults. In order to accommodate fuzzy systems, a membership function weights dependent sliding function is first given. Compared with the existing linear sliding function based results, a reduced‐order fuzzy sliding motion through parallel distributed compensation structure is obtained, then less conservative results are achieved. By exploiting a restricted potential function, a continuous sliding mode fault‐tolerant control scheme is established. Then the closed‐loop system trajectory is maintained in practical sliding mode with a preset sliding band, which improves the robustness performances of system especially for the occurrence of abrupt actuator faults. Moreover, with the usage of the property of fuzzy product inference engines through equivalence class in set theory, a less conservative stability criterion in terms of linear matrix inequalities is derived to guarantee the uniformly boundedness of the reduced‐order sliding motion. At last, some illustrative examples are offered to validate the effectiveness of our proposal.

Disturbance observer-based constrained attitude control for flexible spacecraft

This paper investigates the difficult issue of fixed-time constrained attitude control for a flexible spacecraft under the influence of the system uncertainties, environmental disturbance and abrupt actuator faults. The contributions of the proposed control framework are twofold. Firstly, an observer is presented to precisely reconstruct the uncertain dynamics within a fixed time regardless of the initial estimation error while the settling time is given as a specific parameter. Secondly, using a combination of prescribed performance control (PPC) and barrier Lyapunov function (BLF) approaches, a simple structure constrained attitude control for flexible spacecraft is proposed while desired performance specifications for both quaternion and rotation velocity are indirectly achieved by constraining the sliding manifold. A distinctive feature of the suggested control framework is that the settling time of the closed-loop system is finite and explicitly expressed as two tunable gains even when abrupt actuators faults happen. Numerical simulations substantiate the ability of the offered control to effectively accomplish favorable attitude maneuver under the negative effect of the inertia matrix uncertainty, external disturbances, flexible structures vibration and actuators faults.

Learning-based adaptive fault tolerant control for hypersonic flight vehicles with abrupt actuator faults and finite time prescribed tracking performance

This paper addresses the finite time prescribed performance control problem for hypersonic flight vehicle systems with abrupt actuator faults and time-varying uncertainties. The considered actuator faults contains abrupt gain faults and saltatorial bias faults, and the unknown discontinuous variations of the fault parameters are permitted. In virtue of the finite time performance functions and error transformation, the predefined tracking performance including the convergence time, the tracking error and the overshoot for the velocity and altitude can be ensured. By adaptively estimating the lower bonds of the gain faults and the upper bounds of the bias faults, the unwanted effects of the abruptly faulty actuators can be circumvented. Meanwhile, for the purpose of compensating the unknown nonlinearities, the learning-based control strategy has been employed. Finally, a number of simulation results on the hypersonic flight vehicles are conducted to demonstrate the validity of the proposed approach.

A Descriptor System Approach for Estimation of Incipient Faults With Application to High-Speed Railway Traction Devices

In this paper, a novel descriptor estimator-based incipient fault estimation scheme is designed for Lipschitz nonlinear descriptor systems with process disturbances and measurement output noises. By using the proposed estimator, incipient sensor faults, abrupt actuator faults, and measurement noises can be estimated asymptotically. Application results conducted on a three-phase inverter system of China railway high-speed trains are given to illustrate the effectiveness of the developed approach. The main contributions are summarized in two aspects: 1) the unified framework designed for actuator and sensor fault reconstruction/estimation problem is capable of dealing with actuator and sensor faults at the same time and 2) a linear matrix inequality optimization method is formulated to achieve optimal performance of signal estimation.

Integration of invariant‐set‐based FDI with varying sampling rate virtual actuator and controller

SummaryWe present a new output feedback fault‐tolerant control strategy for continuous‐time linear systems with bounded disturbances. The strategy combines a digital nominal controller under controller‐driven (varying) sampling with virtual actuator (VA)‐based controller reconfiguration to compensate for abrupt actuator faults and invariant‐set‐based fault detection and isolation. Two independent objectives are considered: (a) closed‐loop stability with setpoint tracking and (b) controller reconfiguration under faults. Our main contribution is to extend an existing fault detection and isolation and VA‐based controller reconfiguration strategy to systems under controller‐driven sampling in such a way that if objective (a) is possible under controller‐driven sampling (without VA) and objective (b) is possible under uniform sampling (without controller‐driven sampling), then closed‐loop stability and setpoint tracking will be preserved under both healthy and faulty operations for any possible sampling rate evolution that may be selected by the controller. Copyright © 2015 John Wiley & Sons, Ltd.

비선형 연속 시간 시스템을 위한 적응 고장 진단 관측기 기반 슬라이딩 모드 제어기 설계

In this paper, we propose an AFDO (Adaptive Fault Diagnosis Observer) and a fault tolerant controller for a class of nonlinear continuous-time system under the nonlinear abrupt actuator faults. Together with its estimation laws, the AFDO which estimates that the actuator faults is designed by using the Lyapunov analysis. Then, based on the designed AFDO, an adaptive sliding mode controller is proposed as the fault tolerant controller. Using Lyapunov stability analysis, we also prove the uniform boundedness of the state, the output and the fault estimation errors, and the asymptotic stability of the tracking error under the nonlinear time-varying faults. Finally, we illustrate the effectiveness of the proposed diagnosis method and the control scheme thorough computer simulations.

Robust multiactuator fault‐tolerant MPC design for constrained systems

SUMMARYIn this paper, we present a robust actuator fault‐tolerant control strategy for constrained linear systems in the presence of bounded state and input disturbances. The scheme is based on a bank of state estimators that match different fault situations that can occur in the system. A fault detection and isolation unit verifies that suitable residual variables lie inside pre‐computed sets and selects the estimate that matches the current plant behaviour. A bank of robustly stabilizing tube‐based model predictive control laws is designed, each associated to a fault scenario, and the appropriate controller is selected among them by using the information provided by the fault detection and isolation module. By means of ‘tubes’ of trajectories, we ensure robust closed‐loop exponential stability of the constrained system and good performance in the fault‐free case and under the occurrence of abrupt actuator faults, including actuator outage and loss of effectiveness by an unknown amount. Copyright © 2012 John Wiley & Sons, Ltd.

Bank of Virtual Actuators for Fault Tolerant Control

AbstractWe propose an actuator fault tolerant control scheme based on a bank of virtual actuators (VA), with the novel feature that the virtual actuators implicitly integrate both fault detection and isolation (FDI) and controller reconfiguration (CR) tasks. The bank of VAs operates in closed-loop with an observer-based tracking controller designed for a nominal (fault free) model of the plant. We consider abrupt actuator faults ranging over a finite cover. Each VA is designed to operate appropriately in combination with the nominal controller to achieve correct CR for a particular fault situation in the considered range. A switching rule that engages the suitable VA from the bank is based on sets defined for measurable residual signals constructed directly from the virtual actuators signals. The overall scheme is shown to guarantee closed-loop boundedness and setpoint tracking under all considered fault situations. The method is applied to an example of aircraft lateral control.

Robust MPC multicontroller design for actuator fault tolerance of constrained systems

AbstractIn this paper, we present a robust actuator fault-tolerant control strategy for constrained linear systems, in the presence of bounded state and output disturbances. The scheme is based on a bank of state estimators which match different fault situations that can occur in the system. A fault detection and isolation (FDI) unit verifies that suitable residual variables lie inside pre-computed sets and selects the estimate that matches the current plant behaviour. A bank of robustly stabilising tube-based MPC control laws is designed, each associated to a fault scenario and the appropriate controller is selected among them using the information provided by the FDI module. By means of “tubes” of trajectories, we ensure robust closed-loop exponential stability of the constrained system and good performance in the fault-free case and under the occurrence of abrupt actuator faults.