Sliding Mode Fault Tolerant Control Research Articles

Integral terminal sliding mode fault tolerant control of quadcopter UAV systems

The article presents an active fault-tolerant control scheme with an integral terminal sliding mode controller for the UAV systems. This scheme effectively addresses saturation issues, disturbances, and sensor and actuator faults. Initially, the quadcopter UAV's model is represented in state space form. Subsequently, an augmented system incorporating auxiliary states from sensor faults is developed. An adaptive sliding mode observer is proposed for estimating the actuator and sensor faults. The integral terminal sliding mode fault-tolerant control, designed for altitude and attitude regulation, relies on fault estimation data. In contrast, a cascade proportional-integral-derivative (PID) controller is employed for position control. Simulation results demonstrate the superiority of the proposed method over existing control algorithms.

Neural network-based robust adaptive super-twisting sliding mode fault-tolerant control for a class of tilt tri-rotor UAVs with unmodeled dynamics

Abstract Aiming at alleviating the adverse influence of coupling unmodeled dynamics, actuator faults and external disturbances in the attitude tracking control system of tilt tri-rotor unmanned aerial vehicle (UAVs), a neural network (NN)-based robust adaptive super-twisting sliding mode fault-tolerant control scheme is designed in this paper. Firstly, in order to suppress the unmodeled dynamics coupled with the system states, a dynamic auxiliary signal, exponentially input-to-state practically stability and some special mathematical tools are used. Secondly, benefiting from adaptive control and super-twisting sliding mode control (STSMC), the influence of the unexpected chattering phenomenon of sliding mode control (SMC) and the unknown system parameters can be handled well. Moreover, NNs are employed to estimate and compensate some unknown nonlinear terms decomposed from the system model. Based on a decomposed quadratic Lyapunov function, both the bounded convergence of all signals of the closed-loop system and the stability of the system are proved. Numerical simulations are conducted to demonstrate the effectiveness of the proposed control method for the tilt tri-rotor UAVs.

Data-driven Second-order Sliding Mode Fault-Tolerant Control for a Class of Discrete-time Nonlinear Systems

The current paper presents a data-driven discrete-time integral second-order sliding mode fault-tolerant control (DISSM-FTC) strategy for a category of discrete-time nonlinear systems. The characteristic of the presented control strategy can be easily implemented because it only employs the system's input and output data model through a partial form dynamic linearization (PFDL) approach. At the same time, the fault diagnosis mechanism employs a time-varying threshold with prescribed performance to decide whether a fault occurs or not. Then, the DISSM-FTC method is presented, and a theoretical analysis ensures the stability of the presented strategy. Finally, the efficiency of the presented approach is confirmed through numerical simulations. In contrast to the previous works, the merits of the DISSM-FTC strategy are: 1) the fault-tolerant control problem is solved for the PFDL data model; 2) a novel fault diagnosis mechanism with prescribed performance is proposed; and 3) a data-driven DISSM-FTC method is first proposed.

Finite-time switching-like sliding mode fault-tolerant control for discrete-time cyber-physical systems under DoS attacks and intermittent faults

In this article, the finite-time sliding mode fault-tolerant control problem is addressed for discrete-time cyber-physical systems with intermittent faults and denial-of-service (DoS) attacks. To model the intermittent nature of faults, two sequences of shifted gate functions are employed to depict the fault appearance and disappearance moments. Considering that DoS attacks can prevent transmission of signals, resulting in measurement data losses over the sensor to observer channel, switching-like observer and sliding mode fault-tolerant controller are presented to accommodate both situations with and without attacks. The designed sliding mode fault-tolerant controller can ensure the finite-time reachability of the sliding surface such that it can enter the quasi-sliding mode domain within finite time from any initial state. Moreover, based on the Lyapunov theory, sufficient criteria are derived to guarantee the finite-time boundedness of the closed-loop systems with intermittent faults and DoS attacks in both the reaching and sliding motion phases. Finally, the effectiveness of the proposed sliding mode fault-tolerant control scheme is verified by a numerical example and a practical example.

Event-triggered sliding mode control for networked control systems with actuator faults: Application to gas turbine system

This paper presents an event-triggered sliding mode fault-tolerant control method for networked control systems with actuator faults and external disturbance. First, an event-triggered scheme in the networked control systems is proposed to reduce the number of data transmission. In addition, considering the event-triggering, a sliding mode surface based on the system structure is constructed. Besides, to obtain the controller parameters that meet the [Formula: see text] performance, the bounded real lemma in the form of linear matrix inequality is obtained using the Lyapunov functional. In addition, a sliding mode fault-tolerant control is designed to guarantee that the system can still run stably under the condition of faults and disturbances. Finally, the simulation results of gas turbine system are given to verify the feasibility of the theoretical method.

Robust adaptive fault tolerant control for nonlinear systems with actuator failure and mismatched disturbance

In this paper, a class of nonlinear systems with mismatched disturbance and actuator failure is investigated. A disturbance observer is proposed to estimate the disturbance first and the error of the estimation converges to zero exponentially. By introducing an integral sliding mode surface, the disturbance observer-based integral sliding mode fault tolerant control scheme is proposed to attenuate the disturbance and guarantee the stability of the system. In particular, the control law is designed for decoupling the partial disturbance and attenuating the disturbance that cannot be decoupled. Finally, two examples are given to illustrate the effectiveness of the proposed method.

Efficiency Enhancement Using Fault-Tolerant Sliding Mode Control for the PMVG-Based WTS Under Actuator Faults

This study focuses on efficiency enhancement using fault-tolerant sliding mode control (SMC) for permanent magnet vernier generator (PMVG)-based wind turbine system (WTS) under actuator faults. To do this, the dynamical model of the WTS is constructed with the actuator fault model. Next, the optimum tip speed ratio-based SMC method is proposed to calculate the optimum speed reference of the maximum power point tracking controller that achieves the maximum power capture of the WTS. And then, to effectively track the optimum rotor speed under actuator faults, a disturbance attenuation-based sliding surface is proposed with a novel time-varying exponential reaching law. At the same time, the stability conditions of the SMC are also derived using the appropriate Lyapunov function. Finally, the resilient performance and superiority of the proposed control method are demonstrated through simulation for 5-kW PMVG-based and, 4.8-MW benchmark WTSs and its applicability is proven through an experimental prototype for the 5-kW PMVG-based WTS.

Sliding-mode fault-tolerant control of the six-rotor UAV with dead-zone-input under event-triggered mechanism

This paper investigates the problem of event-triggered mechanism(ETM)-based sliding-mode fault-tolerant control (FTC) for a six-rotor Unmanned Aerial Vehicle (UAV) with dead zone input (DZI) cases, considering potential actuator and sensor faults. Initially, a dynamic ETM is designed, followed by the development of a non-fragile observer utilizing this designed ETM. An integral sliding surface (SS) is then designed in the observation space, and the system is augmented and treated as a variable time delay system. Subsequently, sufficient conditions to ensure the stability of the augmented system with an H∞ performance index γ are obtained using the Lyapunov-Krasovskii function. Next, a sliding mode control (SMC) law is formulated to guide the sliding variables to the SS in finite time. Furthermore, sufficient conditions for ensuring system stability with an H∞ performance index γ are decoupled, and the calculation methods for the non-fragile observer gain matrix and the sliding mode gain matrix are obtained. Finally, to validate the effectiveness of the proposed method in this paper, simulation experiments are conducted.

State estimation and sliding-mode fault-tolerant control of a class of nonlinear systems with actuator faults under the event-triggered mechanism

The current work is an analytical study of the problem of state estimation and fault-tolerant control (FTC) based on dynamic event triggered mechanism (ETM) in the event of actuator fault for a class of nonlinear systems in a network environment. First, a state estimator module is designed in conjunction with the designed dynamic ETM, and an integral sliding surface (SS) is designed in the estimation space to obtain a variable time delay system after augmenting the system by combining the state estimator module and the SS. Second, the sufficient conditions that can make the augmented system stable under the ETM with H∞ performance index are obtained by the Lyapunov–Krasovskii function. The sufficient conditions are decoupled after the design of the sliding mode control (SMC) law that can stabilize the system, and the calculation of the state estimation gain matrix and the SMC gain matrix are obtained. Finally, the effectiveness of the method proposed in this study is verified with two simulation comparison experiments.

Fixed time adaptive fault tolerant sliding mode control of PEMFC air supply system

Guaranteeing rapid management of oxygen excess ratio (OER) for proton exchange membrane fuel cells (PEMFC) under load variations is a challenge with practical significance. To improve the controller response of PEMFC air supply system, a fixed time fault-tolerant control strategy is proposed in this paper. A fixed convergence time of PEMFC air supply control system is quantified and guaranteed by the proposed method and the control response can be accelerated by reducing the setting time. The contributions of this paper is fourfold. Firstly, the manifold leakage fault is estimated by fixed time fault observer, which can improve the real-time fault tracking performance of the control system. Secondly, a hierarchical fixed time sliding mode controller is proposed to regulate the OER rapidly. Furthermore, a novel adaptive term is employed to reduce the effects of the chattering from fault observer in the outer loop. Finally, the effectiveness of the proposed method is verified on a real-time PEMFC simulation platform. Experimental results on a Hardware-in-the-loop (HIL) platform show that the proposed fixed time fault tolerant control strategy has the characteristics of fast response and high robustness.

Fault-Tolerant Control for Carrier-Based Aircraft Based on Adaptive Fuzzy Sliding-Mode Method

Carrier-based aircraft landing involves complex system engineering characterised by strong nonlinearity, significant coupling and susceptibility to environmental disturbances, and autonomous landing of carrier-based aircraft under fault states is even more challenging and riskier. To address the control-system problems of loss of efficiency and performance due to actuator faults and performance degradation due to various unknown disturbances, presented here is fault-tolerant control for carrier-based aircraft based on adaptive fuzzy sliding-mode fault-tolerant control (AFSMFTC). First, three models are built (the carrier-based aircraft fault model, the carrier air wake model and the deck motion model), and the control framework of the autonomous landing control system is introduced. Next, a longitudinal and lateral flight channel controller comprising an adaptive fuzzy network, adaptive laws and a sliding-mode controller is designed using the AFSMFTC method. The adaptive fuzzy network implements fuzzy approximation for the sliding-mode switching terms to further offset errors induced by unknown disturbances, the adaptive laws compensate for actuator faults, and the sliding-mode controller ensures tracking of the overall flight path. Furthermore, the stability of the fault-tolerant method is demonstrated using the Lyapunov function. Finally, simulation and comparative experiments show that the proposed fault-tolerant method has outstanding control performance and strong fault-tolerant capability, thereby providing an effective and feasible solution for designing an autonomous landing system for carrier-based aircraft under fault states.

Particle filter-based adaptive super-twisting sliding mode fault-tolerant control for helicopter systems

Particle filter-based adaptive super-twisting sliding mode fault-tolerant control for helicopter systems

Adaptive Sliding Mode Fault Tolerant Control for Autonomous Vehicle With Unknown Actuator Parameters and Saturated Tire Force Based on the Center of Percussion

Adaptive Sliding Mode Fault Tolerant Control for Autonomous Vehicle With Unknown Actuator Parameters and Saturated Tire Force Based on the Center of Percussion

Anti-disturbance control for HVs system subject to nonlinear actuator characteristics with extended state observer

This paper proposes a radial basis function neural network and the actuator fault extended state observer based fast non-terminal sliding mode fault-tolerant control scheme for hypersonic vehicles (HVs) system. The proposed scheme can cope with actuator faults, actuator saturation, parameter uncertainties, and external disturbances for HVs systems, without relying on redundancy as some passive FTC methods do. Moreover, an anti-windup compensator is designed to mitigate the input saturation effects. Furthermore, the finite-time stability of the attitude angle of the HVs system is proved by Lyapunov's theorem. Numerical simulations validate the effectiveness of the proposed scheme.

Active fault tolerant control based on compound iterative learning observer for trajectory tracking of autonomous underwater vehicles

This article proposes a novel active non-singular integral terminal sliding mode fault tolerant control scheme based on compound iterative learning observer (CILO-NITSM-FTC) for the trajectory tracking control problems of autonomous underwater vehicles (AUVs), which accompanied by nonlinear dynamics and possible thruster failures. The designed compound iterative learning observer (CILO) can effectively estimate the values of nonlinear dynamics and reconstruct the faults of the thrusters. Compared to the existing adaptive non-singular integral terminal sliding mode-based fault tolerant control (ANITSM-FTC), which is a passive fault tolerant control method essentially, the mentioned CILO-NITSM-FTC in this paper presents faster rate of convergence and more accurate control precision. In the design process of CILO, radial basis function neural network (RBFNN) is adopted to estimate the nonlinear dynamics, then approximation errors of neural network, thruster faults and external disturbances are considered as global disturbances. The estimated values obtained from CILO can be used to perform feedforward compensation on the designed controller to complete the reconstruction of thruster faults. Through rigorous mathematical proof and comparative numerical simulation experiments, the superiority and practicability of CILO-NITSM-FTC proposed in this paper are verified.

Operational control for the evolution of enthalpy in an SBR carrying out nitration of 4-chlorobenzotrifluoride and the thermal runway

BackgroundSemi Batch Reactors (SBR) are mostly used to carry out exothermic reactions (synthesis of 4-Chloro-3-Nitrobenzene-tri-fluoride) where a huge amount of heat is evolved. The excess enthalpy generated is removed by the cooling system which encloses the reactor. SBRs are subjected to several uncertainties, external and internal disturbances, and various other faults that occur during the processing of reactants. In the absence of a cooling system, the product starts to decompose yielding gaseous components which raise reactor temperature and pressure, finally leading to thermal runaway. From model-based effective prognosis, it was found that the reaction is very much sensitive to parameters like Damkoler number, activation energy, and the reaction-enthalpy-coefficient. MethodIn order to avoid hazardous situations, a suitable controller must be designed. In this work, a Fault Tolerant Sliding Mode Controller is found to be a promising tool to confront parametric uncertainties, disturbances, and faults. A Fault Tolerant Sliding Mode Observer is designed to observe the unmeasured disturbance and parameters. FindingsNitration of 4-Chlorobenzotrifluoride exhibits both interphase and intraphase mass-transfer phenomenon. The proposed control strategy was demonstrated on the SBR process and compared with the conventional control scheme to check feasibility and effectiveness like cooling rate, computation time, root mean square error, and mean square deviation. To guarantee convergence of the newly developed estimator and stability of the closed-loop controller, Lyapunov criteria are well investigated.

Adaptive Terminal Sliding Mode Fault-Tolerant Control of Spacecraft Based on the Left Attitude Error Function of SO(3)

For the problem of spacecraft attitude actuator failure, an adaptive terminal sliding mode fault-tolerant controller (ATSMFTC) based on the differential manifold SO(3) modelling is designed in this paper. First, SO(3) is used to provide a global and unique description of the spacecraft attitude dynamic model. This modelling method not only avoids the problems of singularity and unwinding that exist in traditional modelling methods but also the SO(3) modelling has a simple formulation of the dynamic equations. Then a left attitude error descriptor function is constructed on SO(3) to design an ATSMFTC. This controller is capable of fast and accurate tracking of the time-varying desired attitude. At the same time, it can react quickly to maintain system stability in case of spacecraft attitude actuator failure. The controller designed based on the left attitude error description system of SO(3) has the features of small computational effort and simple design process. Finally, the numerical simulation of the attitude tracking error verifies the feasibility and high efficiency of the controller designed in this paper.

Finite-time Sliding Mode Fault-tolerant Control for Networked Control Systems With Intermittent Fault Under Event-triggered Scheme

Finite-time Sliding Mode Fault-tolerant Control for Networked Control Systems With Intermittent Fault Under Event-triggered Scheme

Simultaneous Multiplicative and Additive Actuator Faults Estimation-Based Sliding Mode FTC for a Class of Uncertain Nonlinear System

In this article, an adaptive sliding mode fault tolerant control (FTC) is improved in the case of uncertain nonlinear system which is affected by both multiplicative and additive faults in actuator. Especially, when the nonlinear system is modeled by Takagi–Sugeno (T-S) fuzzy system with local nonlinear model. The main contribution of this paper is developing a model of multiplicative faults, which offers a more realistic dynamic evolution of the actuator degradation. The degradation process is modeled by Wiener process and estimated by the maximum likelihood estimation (MLE). Sliding mode observer (SMO) is conceived to realize the additive actuator faults using convex multiobjective optimization. On these bases, the estimated multiplicative and additive actuator faults are used to design the adaptive sliding mode controller (SMC). Finally, the proposed fault-tolerant control scheme is demonstrated by the results of inverted pendulum system simulation.

Observer‐based sliding mode fault tolerant control for nonlinear descriptor systems

AbstractIn this article, the design and analysis of fault tolerant control (FTC) are investigated for stochastic nonlinear descriptor systems by using the sliding mode approach. First, an integral sliding mode‐based descriptor observer (ISM‐DO) is constructed to estimate the state and fault. The proposed ISM‐DO retains the basic characteristics of descriptor systems, meanwhile, it is not only suitable for dual normalized descriptor systems, but also for non‐dual normalized descriptor systems. It is more universal than the existing sliding mode fault tolerant control (SMFTC) methods. In the sequel, a novel restricted equivalent form based algorithm is developed to solve the sliding parameters. The proposed method provides a general algorithm, and it does not impose additional rank constraints. Further, a new adaptive sliding mode fault tolerant controller is constructed to stabilize the fault system, the assumption related to the diffusion matrix is removed. Based on these ingredients, the asymptotically mean square admissibility of the closed‐loop fault system and the observer gain matrix are got by a sufficient linear matrix inequality condition. The effectiveness of the proposed method is verified by simulations.