Sliding Mode Fault Tolerant Control Research Articles

Adaptive Dynamic Surface Integral Sliding Mode Fault-Tolerant Control for Multimachine Excitation Systems with SVC

In this paper, an adaptive dynamic surface integral sliding mode fault-tolerant controller is designed for the multimachine power system with static var compensator (SVC) to overcome the problem of actuator failure. The main features of the proposed method are as follows: (1) By combining the dynamic surface control (DSC) method with integral sliding mode (ISM), the tracking errors of the system converge to the neighborhood of zero within a finite time, and the convergence speed, tracking accuracy, and anti-interference ability of the system are also significantly improved. (2) By introducing the failure factors, an adaptive fault-tolerant controller is designed to ensure the stability of the entire system after partial failure of the actuator. (3) By estimating the norm of the ideal weight vector of the radial basis function neural networks (RBFNNs), the computational burden of the controller is reduced. Finally, the simulation results show the effectiveness of the proposed control scheme.

Sliding mode fault-tolerant control for Takagi-Sugeno fuzzy systems with local nonlinear models: Application to inverted pendulum and cart system

This paper proposes fault-tolerant control design for uncertain nonlinear systems described under Takagi-Sugeno fuzzy systems with local nonlinear models that satisfy the Lipschitz condition. First, by transforming sensor faults as ‘pseudo-actuator’ faults, an adaptive sliding mode observer is designed in order to simultaneously estimate system states, actuator and sensor faults despite the presence of norm-bounded uncertainties. Second, an adaptive sliding mode controller is suggested to provide a solution to stabilize the closed-loop system, even in the event of simultaneous occurrence of faults in actuators and sensors. Next, the main objective of the fault-tolerant control strategy is to compensate for the effects of fault based on the feedback information. Therefore, using the LMI optimization method, sufficient conditions are developed with [Formula: see text] to calculate the gains of the observer and the controller. Then, particular attention is paid to the simultaneous maximization, by convex multi-objective optimization, of the Lipschitz nonlinear constant in Takagi-Sugeno fuzzy modelling and uncertainties attenuation level. The results of the simulation illustrate the effectiveness of our fault-tolerant control approach using a nonlinear inverted pendulum with a cart system.

Sensor/actuator fault tolerant sliding mode control for anti-lock braking in a quarter electric vehicle

This paper proposes a scheme to improve regenerative ABS technology that already exists today by adding accommodation faults to the control system. The nominal control algorithm used is a sliding mode control so that system nonlinearities can be handled properly. The proposed method then is called sensor/actuator fault tolerant sliding mode control system. In designing the proposed control, there are two stages, namely estimation of faults, as well as the active mechanism for reconfiguring controls. Estimation of faults is done by using proportional-integral (PI) observers based on extended state space equation. Whereas the control signal reconfiguration is done actively by replacing measured output with their estimates and compensating for control signal using the actuator fault estimate. The simulation shows that the control system based on the proposed algorithm produces better dynamic performance than the sliding mode control (SMC) without fault tolerant feature. Furthermore, the system provides inherent characteristic for dealing with a minor fault in the hydraulic actuator.

Backstepping‐based sliding mode fault‐tolerant control for linear interconnected parabolic distributed parameter systems

This study considers the fault-tolerant control (FTC) issue for a class of linear interconnected parabolic distributed parameter systems by utilising the backstepping-based sliding mode control technique. The original interconnected system, which suffers from process/actuator faults and matched disturbances, is converted into a stable target system by using an invertible backstepping transformation. Two types of kernel functions, the distinct diffusivity and the same diffusivity, are obtained. A sliding mode FTC scheme is developed to eliminate the destabilising effects caused by process/actuator faults and matched disturbances. An industrial application example is presented to validate the applicability and the relevance of the developed methodology.

Sliding mode fault-tolerant control for unmanned marine vehicles with signal quantization and time-delay

This paper deals with the adaptive sliding mode fault-tolerant control problem for unmanned marine vehicles (UMVs) with signal quantization and state time-delay. A unified thruster fault model for UMVs is built by taking bias, partial, total, time-varying stuck, and hard-over faults into account. For UMVs in the network environment, the effects of quantization and state time-delay on UMVs are inevitable. In this situation, adaptive sliding mode technology and dynamic quantization parameter adjustment strategy are combined to compensate for the quantization errors and time-delay effects. Compared with the traditional method, a larger quantization parameter adjustment range is given and a new dynamic quantization parameter adjustment strategy is designed. Further the quantized sliding mode fault-tolerant controller independent of fault detection and diagnosis mechanism is designed for UMVs in the presence of time-delay and various thruster faults to reduce the oscillation amplitudes of the yaw velocity error. The comparison simulations of a typical floating production ship have been provided to demonstrate the effectiveness of the proposed algorithm.

Asynchronous fault-tolerant control for stochastic jumping singularly perturbed systems: An H∞ sliding mode control scheme

This work studies the asynchronous fault-tolerant sliding mode control for uncertain stochastic jumping systems subject to singular perturbations, in which the controller is assumed to be able to estimate the hidden system mode through a detector with a conditional probability via the hidden-Markov model. Additionally, in consideration of avoiding the system performance decreases generated by the actuator degradation, the synthesized fault-tolerant sliding mode control scheme is first employed. Through applying a common singularly perturbed parameter based sliding surface, this paper attempts to construct a proper asynchronous sliding mode control law that can ensure not only the reachability but also the closed-loop system is stable with an expected H∞ performance index. By virtue of the mode-dependent Lyapunov function and the hidden-Markov model approach, sufficient conditions are acquired. Besides, solving linear matrix inequalities for obtaining the control gain matrices are given through the convex optimization theory. Eventually, the effectiveness and feasibility of the proposed asynchronous fault-tolerant sliding mode control scheme are verified by a numerical example.

Dynamic event-triggered fault estimation and sliding mode fault-tolerant control for networked control systems with sensor faults

This paper investigates the problem of fault estimation and sliding mode fault-tolerant control(FTC) for networked control systems with sensor faults under dynamic event-triggered scheme. First, the sensor faults are equivalent to virtual internal system faults in system by filtering, and dynamic event-triggered fault/state observer is designed to estimate the system state and fault at the same time. Therefore, a sliding mode surface under event-triggering is constructed considering system faults and network delay. By the Lyapunov-Krasovskii function, a novel design condition in the form of linear matrix inequality is obtained with H∞ performance to gain observer and controller parameters. In addition, a sliding mode FTC law is constructed to guarantee that the trajectories of system states can be arrived to the sliding surface in a finite time. Finally, two examples with simulation are given to verify the effectiveness of the theoretical method.

Event trigger-based adaptive sliding mode fault-tolerant control for dynamic systems

Event trigger-based adaptive sliding mode fault-tolerant control for dynamic systems

Adaptive Sliding Mode Fault-Tolerant Control for Uncertain Systems with Time Delay

In this work, an adaptive sliding mode fault-tolerant controller is proposed for a class of uncertain systems with time delay. The integral term is added to the traditional sliding surface to improve the robustness of the control system, and then a type of special sliding surface is designed to cancel the reaching mode based on global sliding mode method. Without the need for fault detection and isolation, an adaptive law is proposed to estimate the value of actuator faults, and an adaptive sliding mode fault-tolerant controller is designed to guarantee the asymptotic stability of sliding dynamics. Finally, the presented control scheme is applied to the position control of a Qball-X4 quad-rotor UAV model to verify the effectiveness.

Robust Fault Tolerant Control Design for Nonlinear Systems not Satisfying Matching and Minimum Phase Conditions

This paper proposes an adaptive sliding mode fault tolerant control design for lipschitz nonlinear system subject to simultaneous actuator and sensor faults. First, in order to estimate the system states, actuator and sensor faults, only one observer with an adaptive nonlinear gain is required where the minimum phase condition is relaxed to delectability and the matching condition is weakened to become a condition related to the system dimensions. Furthermore, our approach is applicable where there are faults greater than outputs. Next, a virtual sensor technique is developed to replace a failed, missing or corrupted sensor to provide a signal having the same effect of the nominal sensor. Then, this study provides an adaptive sliding mode fault tolerant control to achieve an optimal interaction between observer, virtual sensor and controller models. Thus, using the LMI technique with multiobjective optimization performance, sufficient conditions are derived to ensure the closed-loop Lipschitz nonlinear system stability and guarantee that the Lipschitz set of the adaptive sliding mode observer is a subset of the adaptive sliding mode control Lipschitz set. Two illustrative examples the first is the robotic manipulator model and the second is the longitudinal dynamics of the following vehicle system were performed to verify the effectiveness of the proposed approach.

An anti-unwinding finite time fault tolerant sliding mode control of a satellite based on accurate estimation of inertia moments

Design of an adaptive anti-unwinding finite time sliding mode algorithm for attitude control system of a three-axis satellite is approached in this paper. In the designed controller, some parameters updating laws are proposed to simultaneously obtain the accurate values of inertia moments, the upper values of reaction wheels’ failures and disturbances. Accordingly, the combined finite time stability of the control system and convergence of the satellite parameters has been demonstrated. Also, a new sliding surface is suggested to avoid the unwinding problem which is common in sliding mode techniques. It is proved by the Lyaponov methodology that the satellite quaternions and angular velocities always approach to the nearest equilibrium point and so it prevents the excessive satellite slews. Furthermore, the proposed algorithm has been modified in such a way that the singularity problem does not occur, especially when the system states reach around the equilibrium point. Therefore, the finite time convergence of system states and parameters estimation errors are guaranteed subjected to disturbances and actuator failures without occurring singularity and unwinding problems. Besides rigorous theoretical proofs by the Lyapunov theory, different simulations are exhibited to demonstrate the merits of the developed control schemes.

Flight evaluation of a sliding mode online control allocation scheme for fault tolerant control

This paper develops a sliding mode fault tolerant control scheme based on a Linear Parameter Varying (LPV) system representation of the plant. The scheme includes a control allocation component, which is capable of utilizing the available healthy actuators in the face of actuator faults/failures, in an effort to retain close to nominal fault free performance. The proposed scheme is validated using the Japan Aerospace Exploration Agency’s Multi-Purpose Aviation Laboratory (MuPAL-α) research aircraft. The flight test results demonstrate good lateral-directional state tracking performance with no visible performance degradation in the presence of rudder and aileron faults.

Neural Networks-Based Sliding Mode Fault-Tolerant Control for High-Speed Trains With Bounded Parameters and Actuator Faults

In this paper, novel adaptive fault-tolerant control (FTC) algorithms are put forward to address the position and velocity tracking control problems of high-speed trains (HSTs). The basic running resistances, additional resistances and interactive forces between the connected carriages are taken into account. On account of the system uncertainties, a novel multidimensional sliding mode surface with time-varying parameters estimated by the adaptive technique is proposed. And neural networks (NNS) are made use of approximating the additional resistances viewed as a bounded disturbance. Two cases for system parameters are taken into consideration: 1) Parameters with unknown boundary are unknown; 2) Parameters with known upper and lower boundary are unknown. As for the former, the unknown parameters are formulated via formal mathematical expression with indicator functions and the adaptive technique is introduced; As for the latter, a continuous functions related to the above multidimensional sliding mode surface is defined and the adaptive technique with Project functions is designed, which guarantees saturation characteristics of the presented controller. The closed-loop system stability can be proved by means of the Lyapunov theory and the feasibility and effectiveness of the presented control schemes can be revealed via simulation experiments.

Self-Healing Control for Large Launch Vehicle Based on Extended State Observer and Adaptive Dynamic Programming

This paper investigates the self-healing control problem for the large launch vehicle (LLV) with system uncertainties, external disturbances, and actuator faults. First, the attitude dynamics of the LLV are presented, and the control-oriented model subject to undesired malfunctions is structured. Second, a novel extended state observer (ESO) is designed to estimate the disturbances and fault informations, and the nonlinear gain functions with two different linear ranges are introduced to improve the estimation accuracy and reduce the effect of peaking value problem. Then, an integral terminal sliding mode fault tolerant control scheme is proposed for the attitude faulty system, which would stabilize the closed-loop system even existing the disturbances and actuator failures. Besides, utilizing the adaptive dynamic programming (ADP) technique, a supplementary control with actor-critic structure is employed to further improve the system tracking performance and provide the additional compensation control input according to the bias between the desired value and actual one. Finally, the effectiveness of the proposed method is verified by the simulation results.

Sensor Fault Diagnosis and Fault Tolerant Control for Forklift Based on Sliding Mode Theory

For the forklift equipped with electrical sensors, a fault tolerant control (FTC) strategy is proposed. First, considering the uncertainty of forklift cargo and the external output disturbance, the equivalent sensor fault model of forklift is constructed. Then, a sliding mode observer (SMO) with adaptive regulation law is proposed to solve the problem that some fault reconstruction methods demand the upper bound of faults. Based on the fault value reconstructed by SMO, a sliding mode fault-tolerant controller is designed. It can realize active FTC of typical sensor faults of forklift in the presence of uncertainties and output disturbance. Finally, experiment is given to verify the effectiveness of the proposed FTC strategy.

Adaptive Fault-Tolerant Sliding Mode Control for High-Speed Trains With Actuator Faults Under Strong Winds

This article addresses the fault-tolerant control problem for high-speed trains (HSTs) with actuator faults under strong winds. For the healthy system, a non-singular fast terminal sliding mode surface is introduced into the controller, which ensures the system fast converge to the equilibrium point with finite time, and the radial basis function neural network (RBFNN) with the adaptive compensation term of the error is used to approximate the unknown nonlinear disturbances of the train system in strong winds and predict the time delay generated in the train communication network. Through the RBFNN observer established specifically for actuator failures, the real effective factors are identified. Combining with the identified effective factors and predicted time delay, an adaptive fault-tolerant sliding mode control method is established for train systems. With dynamic parameters and position update strategy guided by negative gradient thought, an improved particle swarm optimization algorithm is proposed to optimize the uncertain parameters of control method, which weakens the chattering phenomenon from the sliding mode controller and improves the control accuracy. Simulation results show that the proposed method has better tracking performance and real-time performance compared with other fault-tolerant control methods under various operating conditions, which ensures the running safety of HSTs under different strong winds.

Fault-Tolerant Sliding Mode Control of a Quadrotor UAV with Delayed Feedback

Fault-Tolerant Sliding Mode Control of a Quadrotor UAV with Delayed Feedback

Fixed-Time Fault-Tolerant Attitude Tracking Control for Rigid Spacecraft

Abstract This paper addresses the fixed-time attitude tracking problem of rigid spacecraft with inertial uncertainties, external disturbances, and partial loss of actuator effectiveness faults. A new fixed-time terminal sliding surface is proposed and a singularity-free fixed-time fault-tolerant sliding mode control (FTSMC) is designed. It is proved that the proposed FTSMC can ensure that the attitude tracking errors converge to an arbitrary small bound centered on the equilibrium point within fixed time and then go to the equilibrium point asymptotically. The appealing features of the proposed control are fixed-time tracking stability featuring fast convergence, high precision, and strong robustness. Simulations verify the effectiveness of the proposed approach.

Robust fault-tolerant attitude tracking with guaranteed prescribed performance

The robust fault-tolerant (FT) attitude tracking control problem with guaranteed prescribed performance is addressed in this paper. We consider the actuator fault, misalignment, sensor fault and external disturbance simultaneously and incorporate the L2 control allocation (CA) method to minimize the use of faulty actuators. To guarantee the prescribed performance such as the steady-state tracking error, convergence rate, as well as overshoot and undershoot, the constrained quaternion error is transformed to an unconstrained state, whose stabilization is proven to be sufficient and necessary to guarantee the performance requirement. With the utilization of the transformed state and the compromised angular velocity error suffering from gyro faults, a novel adaptive sliding mode FT control law with CA is developed. Ultimate uniform boundedness of the compromised angular velocity error and transformed state is ensured to satisfy the specified tracking performance. Numerical simulations are conducted on a rigid spacecraft to illustrate the efficiency of the proposed robust FT control law.

Sliding‐mode fault‐tolerant control using the control allocation scheme

SummaryThis paper is devoted to the design of a novel fault‐tolerant control (FTC) using the combination of a robust sliding‐mode control (SMC) strategy and a control allocation (CA) algorithm, referred to as a CA‐based sliding‐mode FTC (SMFTC). The proposed SMFTC can also be considered a modular‐design control strategy. In this approach, first, a high‐level SMC, designed without detailed knowledge of systems' actuators/effectors, commands a vector of virtual control signals to meet the overall control objectives. Then, a CA algorithm distributes the virtual control efforts among the healthy actuators/effectors using the real‐time information obtained from a fault detection and reconstruction mechanism. As the underlying system is not assumed to have a rank‐deficient input matrix, the control allocator module is visible to the SMC module resulting in an uncertainty. Hence, the virtual control, in this scheme, is designed to be robust against uncertainties emanating from the visibility of the control allocator to the controller and imperfections in the estimated effectiveness gain. The proposed CA‐based SMFTC scheme is a unified FTC, which does not need to reconfigure the control system in the case of actuator fault or failure. Additionally, to cope with actuator saturation limits, a novel redistributed pseudoinverse‐based CA mechanism is proposed. The effectiveness of the proposed schemes is discussed with a numerical example.