Robust Fault-tolerant Control Research Articles

Robust fault-tolerant preview control for automatic landing of carrier-based aircraft

Robust fault-tolerant preview control for automatic landing of carrier-based aircraft

A robust fault-tolerant control algorithm based on a novel modeling method for quadrotor application with accurate fault estimation

A robust fault-tolerant control algorithm based on a novel modeling method for quadrotor application with accurate fault estimation

Robust fault-tolerant control for dynamic positioning of ships with prescribed performance

This study presents a new fault-tolerant control scheme for ship dynamic positioning. The scheme aims to handle unknown disturbances, imprecise fault estimation, and control input constraints. First, an adaptive sliding mode disturbance observer is introduced. This observer effectively reconstructs disturbances in finite time, even without knowledge of their derivative upper bounds. Next, we design a novel prescribed performance function that sets bounds on tracking errors. This function is combined with an auxiliary intermediate control technique to create a high-level controller. Lastly, a robust fault-tolerant control allocation scheme is proposed to redistribute the generalized forces among faulty actuators. It autonomously finds a feasible force vector in the attainable force set. Simulation results are provided to demonstrate the effectiveness of the proposed control scheme.

Event-triggered robust fault-tolerant control of a class of Euler–Bernoulli beam equations via sliding mode control

Event-triggered robust fault-tolerant control of a class of Euler–Bernoulli beam equations via sliding mode control

VGESO-Based Finite-Time Fault-Tolerant Tracking Control for Quadrotor Unmanned Aerial Vehicle

Based on the variable gain extended state observer, a finite-time fault-tolerant control strategy is developed for the quadrotor unmanned aerial vehicle with actuator faults and external disturbances. Firstly, a novel variable gain extended state observer is designed to estimate the unknown external disturbances, which mitigates the initial peaking phenomenon existing in traditional extended state observer-based methods. Meanwhile, the neural networks are applied to accurately approximate unknown couplings online. Moreover, with the help of the projection operator technique, the unknown actuator faults are observed in real time. Combined with the backstepping framework, the finite-time robust fault-tolerant control scheme is constructed and the stability is strictly proved via Lyapunov’s theory. Finally, the validity of the developed control scheme is demonstrated through numerical simulations.

Observer‐based fault tolerant control for a class of nonlinear multi‐agent systems with sensor faults

AbstractThis article focuses on the robust fault tolerant control (FTC) problem for a class of Lipschitz nonlinear multi‐agent systems(MASs) subject to sensor faults. Firstly, sensor faults are transformed into actuator faults via introducing a new intermediate auxiliary state variable, and a distributed adaptive fault estimation observer is designed to estimate the state information and the concerned faults by using the relative output estimation error. Then, the sufficient existence conditions for the observer to satisfy the robust performance index are given. Thirdly, based on the results of observer design, a new design method of dynamic output feedback controller is proposed to implement consensus of MASs and ensure the desired disturbance rejection performance. Finally, the simulation results are presented to illustrate the effectiveness of the proposed method.

Fixed-Wing UAV Formation Robust Fault-Tolerant Control With Switching Topologies

Fixed-Wing UAV Formation Robust Fault-Tolerant Control With Switching Topologies

Finite-time sliding-mode observer based distributed robust fault tolerant control for multi-agent systems against actuator and sensor faults

The faults of actuators and sensors have adverse impacts on the distributed control of the multi-agent systems (MASs). This study addresses the problem of fault-tolerant control (FTC) for MAS subject to actuator and sensor faults. The descriptor approach is introduced to transform the MAS dynamics into a descriptor form, in which the actuator and sensor faults are integrated as components of the extended descriptor system state. A sliding mode-based unknown input observer is designed to realise finite-time fault diagnosis and state estimation for the transformed descriptor system. Furthermore, based on the estimation, a distributed robust FTC protocol is developed to guarantee the consensus of MAS against the actuator and sensor faults. Finally, simulations are conducted to validate the effectiveness of the proposed approach.

Research on robust fault-tolerant control of the controllable suspension based on knowledge-data fusion driven

For the robust fault-tolerant control of the controllable suspension system, a control strategy driven by knowledge-data fusion is proposed. Firstly, the boundary fuzziness between perturbation type uncertainty and gain type fault is analyzed, and then a data-driven method is introduced to avoid the state estimation of system uncertainty and fault. The proximal policy optimization algorithm in reinforcement learning is selected to construct a “data control law”, to deal with uncertainty and fault. On the other hand, based on the classical sky-hook control, the “knowledge control law” for system performance optimization is designed, taking into account the nonlinear and non-stationary characteristics of the system. Furthermore, the dependency between robust fault tolerance and performance optimization control is revealed, and the two control laws are fused by numerical multiplication, to realize the performance matching optimization control of robust fault tolerance of controllable suspension system driven by knowledge-data fusion. Finally, the effectiveness and feasibility of the proposed method are verified by the simulation and real-time experiment of non-stationary excitation and near-stationary excitation under the combination of uncertainty and fault.

Active fault-tolerant control for the dual-valve hydraulic system with unknown dead-zone

This paper proposes a method for high-performance motion control of the dual-valve hydraulic system subject to parameter and model uncertainties, unknown proportional valve dead-zone, and servo valve fault. By constructing a detailed dual-valve fault system model (DFSM), a disturbance observer-based adaptive robust fault-tolerant controller is proposed via the backstepping method. This controller integrates a model-based fault detection algorithm for real-time fault monitoring and subsequent controller reconfiguration. Additionally, the DFSM-based adaptive robust control (ARC) technique is applied to handle the unknown dead-zone problem and other nonlinearities, ensuring precise control. Once the servo valve fault occurs, a nonlinear observer estimates the fault and collaborates with the ARC to establish a reconfigured controller, thereby maintaining motion control. The effectiveness of the proposed method has been experimentally verified.

Fault Mode Analysis and Convex Optimization-Based Fault-Tolerant Control for New Type Dissimilar Redundant Actuation System of Near Space Vehicle

A new type dissimilar redundant actuation system (NT-DRAS), which is composed of an electro-hydrostatic actuator (EHA) and an electro-mechanical actuator (EMA), is applied in high value unmanned aerial vehicles such as the future near space vehicles to improve their reliability and performance index simultaneously. Further improvement in the flight safety is achieved with the fault-tolerant control (FTC) technique which deals with system faults. This paper proposes a novel convex optimization-based fault-tolerant control (CO-FTC) strategy for the NT-DRAS subject to gradual faults which are included in the state space representation of the system. A convex analysis-based treatment for system uncertainty caused by gradual faults is applied to determine the control gain matrix. The existence condition of the control gain matrix is optimized in the linear matrix inequality (LMI) form. Finally, the determined subsystems based on the novel technique is used to solve the modeled robust FTC problem. Case studies of NT-DRAS subject to different gradual faults have been accomplished to illustrate the FTC necessity for NT-DRAS. Furthermore, the effectiveness of the proposed CO-FTC strategy is validated by comparative analysis of the simulation results.

Robust fault-tolerant control of a class of uncertain nonlinear switched systems with actuator saturation

This paper addresses the robust fault-tolerant control problem for a class of uncertain nonlinear switched systems with actuator saturation. Our aim is to design a switching law and a robust fault-tolerant control law for guaranteeing that the closed-loop system is asymptotically stabilizable, while at the same time the attraction domain estimation is as large as possible. By using the multiple Lyapunov functions method, sufficient conditions for robust fault-tolerant stabilisation are proposed for the closed-loop system. Then, when some scalar parameters are given in advance, the problem of fault-tolerant controller design and attraction domain estimation is transformed into a convex optimisation problem with linear matrix inequality (LMI) constraints. Finally the validity of the proposed design method is verified by a numerical example.

Reliability improvement of the large-scale wind turbines with actuator faults using a robust fault-tolerant synergetic pitch control

This study addresses the critical issue of enhancing the reliability of large-scale wind turbines in the presence of simultaneous pitch actuator faults. To do this, a fault-tolerant finite-time continuous nonsingular terminal synergetic control manifold is firstly designed and incorporated into the pitch control system to improve precision tracking performance and regulation of the pitch angle for stable power extraction under extreme wind conditions. Besides, the proposed scheme is model-independent, easily accessible, and features fast finite-time convergence. At the same time, the mismatched disturbance observer is designed to attenuate the time-varying perturbations of the wind turbine system (WTS) to achieve robustness and high tracking accuracy. Then, the proposed scheme’s stability conditions and finite-time convergence analysis are derived using the Lyapunov theory. Finally, the simulation and comparative studies are presented to signify the reliable performance of the proposed control method for both a 4.8 MW benchmark WTS and a large-scale 20 MW PMSG-based WTS to verify robustness against simultaneous pitch actuator faults and uncertainties.

Event-triggered adaptive robust fault-tolerant control for a class of uncertain switched nonlinear systems

In this paper, the adaptive robust fault-tolerant control problem for a class of switched nonlinear systems with parameter uncertainty, disturbances and actuator failures is concerned based on event-triggered control strategy. The adaptive laws based on state-dependent switched strategy are designed to eliminate the effects of actuator faults and parameter uncertainties by using the estimations of the unknown upper bounds of uncertain parameters. Then, the robust fault-tolerant technique and multiple Lyapunov functions method are used, the designed controller can guarantee that all signals of the switched closed-loop systems are uniformly bounded. Meanwhile, the desired performance of the systems is promised. Finally, the simulation results are given to illustrate the effectiveness of the proposed design method.

Robust Fault Estimation and Fault-Tolerant Control for Discrete-Time Systems Subject to Periodic Disturbances

To enhance the reliability of digital automation systems in the Industry 4.0 era, this paper investigates a robust fault-tolerant control scheme in the discrete-time domain subject to periodic disturbances, consisting of a fault estimator, dynamic disturbance compensation loop, and fault-tolerant controller. The fault estimator simultaneously estimates both the system states and actuator/sensor faults. The existence and stability conditions of the proposed estimator are given, and a robust design method is proposed to make the state estimates robust to disturbances. To further reduce the estimation errors caused by periodic disturbances, a novel disturbance compensation loop is introduced and is optimized by a joint zero-assignment and pole-optimization method to delicately compensate for the adverse impacts of periodic input disturbances. The proposed robust fault-tolerant controller uses fault estimation to ensure fast recovery in the event of bounded actuator/sensor faults. The proposed scheme is evaluated through simulations of a two-wheeled mobile robot subject to periodic disturbances and simultaneous abrupt inclination angular sensor and ramp actuator faults, where its performance is shown to exceed that of existing methods.

Fault-tolerant attitude coordination control for multiple flexible spacecraft using vector measurements

This paper addresses the control problems of distributed attitude coordination for multiple flexible spacecraft based on the feedback of inertial vector measurements. It is assumed that the angular velocity information is not available, and the modal variable cannot be measured. The orientation error model with vector measurements is introduced. And then the distributed attitude synchronization control scheme is presented without actuator faults or disturbances. It is guaranteed that the desired equilibrium is locally asymptotically stable and the undesired equilibrium is unstable. Meanwhile, the domain of attraction is given by inequality constraints. In the case that there exist actuator faults and external disturbances, a robust fault-tolerant control strategy is developed to realize attitude synchronization. The hyperbolic tangent function in place of sign function is adopted to eliminate external disturbances. Meanwhile, the adaptive laws are proposed to estimate actuator faults. The salient feature of these control approaches is that no modal variable observers are utilized and the control schemes are robust to the inertia uncertainty of spacecraft. Finally, numerical simulations are implemented to manifest the validity of the presented control schemes.

Robust control scheme based on an uncertainty and disturbance estimator for a quadrotor with motor failures

AbstractThis paper proposes a new robust fault tolerant control architecture based on a disturbance observer. The control architecture is composed of a nominal controller and a rotor's fault observer capable to identify and estimate motors' degradation performance. Besides, is designed for a quadrotor vehicle and validated in critical and noncritical motors' failures. For both failure cases, each motor performance is analyzed to counteracted the failure and restore the system stability. If the practical stability is not recovered (critical case) a control reconfiguration is performed for safe landing. Experimental tests are carried out in real time to illustrate the effectiveness of the proposed architecture when confronting the stability of the system with aggressive disturbances or uncertainties.

INDUCTIVE COUPLER FOR BATTERY CHARGING SYSTEM OF HEAVY ELECTRIC VEHICLES

This paper proposes a robust fault-tolerant control (FTC) for the dual three-phase (DTP) induction machines under failures controlled by a higher-order sliding mode control strategy. However, the DTP induction machine is increasingly used because of better reliability and a supply division. A passive and an active FTC law have been designed and tested on DTP. The proposed method not only realizes the FTC and the fault elimination but also provides a possible solution for emulating a traction system using a direct continue machine (DCM) supplied by a four-quadrant chopper. Therefore, the emulation system is based on a controlled DCM, which imposes the same behavior of the mechanical power train of an electric vehicle to the DTP. Simulation results are given to verify the robustness and good performance of the proposed fault-tolerant control scheme.

NONLINEAR FAULT TOLERANT CONTROL OF DUAL THREE-PHASE INDUCTION MACHINES BASED ELECTRIC VEHICLES

This paper proposes a robust fault-tolerant control (FTC) for the dual three-phase (DTP) induction machines under failures and which is controlled by a higher-order sliding mode control strategy. However, the DTP induction machine is increasingly used because of its advantages such as better reliability and supply division, both passive and active FTC laws have been designed and tested on DTP. The proposed method not only realizes the FTC and the fault elimination as well but also provides a possible solution for emulating a traction system using a direct continue machine (DCM) supplied by a four-quadrant chopper. Therefore, the emulation system is based on a controlled DCM, which imposes the same behavior of the mechanical power train of an electric vehicle to the DTP. Simulation results are given to verify the robustness and good performance of the proposed fault-tolerant control scheme.

Nonlinear Robust Fault-Tolerant Tracking Control of a Tri-Rotor UAV against Actuator’s Abnormal Behavior

In this paper, a new nonlinear robust fault-tolerant tracking control method is proposed for a tri-rotor unmanned aerial vehicle (UAV) under unknown abnormal actuator behaviors together with unknown external disturbances. The actuator anomalies are modeled as time-varying multiplicative parameters to improve the model accuracy. The control system is decoupled into two parts, including the inner-loop attitude control and the outer-loop position control. The radial basis function neural network (RBFNN) is utilized in the outer loop to estimate the actuator anomalies and external disturbances, and then the state feedback controller is employed for the position tracking of the UAV. Then, the robust integral of the signum of the error (RISE) controller is designed for the inner loop to compensate for actuator anomalies and external disturbances. The composite stability of the closed-loop system and the asymptotical tracking performance are proved via a Lyapunov-based stability analysis. Numerical simulations based on the proposed fault tolerant control (FTC) scheme as well as the comparison results with a sliding mode-based FTC method validate the effectiveness and better performance of the proposed control design.