scholarly journals Asynchronous Adaptive Fault-Tolerant Control for Networked Stochastic Unmanned Surface Vehicles with Multiple Types of Actuator Faults

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Ai-Min Wang ◽  
Jian-Ning Li ◽  
Xiao-Bin Xu

This paper aims to design an asynchronous adaptive fault-tolerant controller for the networked stochastic unmanned surface vehicles (NSUSVs) subject to multiple types of actuator faults and external disturbance. The partial fault and bias fault of the actuator are taken into consideration simultaneously. By estimating online the unknown bias fault of the actuator and the external disturbances, the proposed adaptive fault-tolerant controller can automatically compensate for these impacts produced by actuator faults and external perturbation while preserving the uniformly ultimate boundedness of the solutions. Both the faulty actuator and the designed controller are asynchronous with the NSUSVs. Moreover, a mode-dependent adaptive event-triggered mechanism (AETM) is introduced in order to facilitate network resources utilization. Finally, the effectiveness and correctness of the proposed design scheme are verified by a numerical example.

Author(s):  
Ai-Min Wang ◽  
Jian-Ning Li

This article focuses on the design of event-triggered asynchronous [Formula: see text] fault-tolerant controller for Markov jump system subject to actuator faults and external disturbances. The asynchronization phenomenon not only occurs between the controlled system and controller but also exists between the controlled system and faulty actuator, which are portrayed as two corresponding hidden Markov models. Moreover, a mode-dependent event-triggered mechanism is introduced to facilitate network resources utilization. Then, by introducing mode-dependent Lyapunov-Krasovskii functional, a sufficient condition is obtained to guarantee that the closed-loop system is randomly mean square stable with [Formula: see text] performance. Finally, two numerical examples are employed to illustrate the effectiveness of the proposed synthesis scheme.


Author(s):  
Guoqing Zhang ◽  
Shen Gao ◽  
Jiqiang Li ◽  
Weidong Zhang

This study investigates the course-tracking problem for the unmanned surface vehicle in the presence of constraints of the actuator faults, control gain uncertainties, and environmental disturbance. A novel event-triggered robust neural control algorithm is proposed by fusing the robust neural damping technique and the event-triggered input mechanism. In the algorithm, no prior information of the system model about the unknown yawing dynamic parameters and unknown external disturbances is required. The transmission burden between the controller and the actuator could be relieved. Moreover, the control gain-related uncertainties and the unknown actuator faults are compensated through two updated online adaptive parameters. Sufficient effort has been made to verify the semi-global uniform ultimate bounded stability for the closed-loop system based on Lyapunov stability theory. Finally, simulation results are presented to illustrate the effectiveness and superiority of the proposed algorithm.


Author(s):  
Zhong-Zhe Yue ◽  
Jing-Guang Sun

This study investigates the flight longitudinal tracking control problem of hypersonic vehicle in presence of the input saturation, external disturbances, model parametric uncertainties, and actuator faults. First, the velocity and altitude subsystem are established with disturbances based on the feedback linearization model. Second, two robust anti-saturation fault-tolerant controllers are designed for the velocity subsystem and altitude subsystem by the utilization of the tangent function, Nussbaum function, and adaptive nonlinear filter. Finally, Lyapunov stability theory is used to prove that the states of the closed-loop system are bounded. And, the effectiveness and robustness of the control strategy are proved by numerical simulations.


Author(s):  
Syed Muhammad Amrr ◽  
M Nabi ◽  
Pyare Mohan Tiwari

This paper investigates the application of an integral sliding mode control with a robust nonlinear disturbance observer to obtain an anti-unwinding spacecraft attitude tracking response with robustness against external disturbances, inertia matrix uncertainties, and actuator faults. In the controller design, external disturbances, uncertainties, and actuator faults are lumped together and estimated by the robust nonlinear disturbance observer. The proposed robust nonlinear disturbance observer guarantees the convergence of estimated lumped disturbance error to origin in finite time. The estimated disturbance is then used in the controller as a feed-forward compensator. Further, an adaptive law is also incorporated in the proposed controller to ensure additional robustness. The stability of the overall system and anti-unwinding characteristic are proved using the Lyapunov stability theory. Finally, numerical simulation analysis is performed in the presence of all the sources of lumped disturbances. It is observed that the proposed control strategy is ensuring higher accuracy, good steady-state precision, and eliminates the unwinding phenomenon.


Author(s):  
Bing Xiao ◽  
Qinglei Hu ◽  
Michael I. Friswell

This paper investigates the design of spacecraft attitude stabilization controllers that are robust against actuator faults and external disturbances. A nominal controller is developed initially, using the adaptive backstepping technique, to stabilize asymptotically the spacecraft attitude when the actuators are fault-free. Additive faults and the partial loss of actuator effectiveness are considered simultaneously and an auxiliary controller is designed in addition to the nominal controller to compensate for the system faults. This auxiliary controller does not use any fault detection and isolation mechanism to detect, separate, and identify the actuator faults online. The attitude orientation and angular velocity of the closed-loop system asymptotically converge to zero despite actuator faults providing the nominal attitude system is asymptotically stable. Numerical simulation results are presented that demonstrate the closed-loop performance benefits of the proposed control law and illustrate its robustness to external disturbances and actuator faults.


2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
Gang Chen ◽  
Qing Lin

This paper investigates the cooperative tracking control problem for networked uncertain Lagrange systems with a leader-follower structure on digraphs. Since the leader’s information is only available to a portion of the followers, finite-time observers are designed to estimate the leader’s velocity. Based on the estimated velocity information and the universal approximation ability of fuzzy logic systems, a distributed adaptive fuzzy tracking control protocol is first proposed for the fault-free Lagrange systems. Then, the actuator faults are considered and a distributed fault-tolerant controller is presented. Based on graph theory and Lyapunov theory, the convergence analyses for the proposed algorithms are provided. The development in this paper is suitable for the general directed communication topology. Numerical simulation results are presented to show the closed-loop performance of the proposed control law and illustrate its robustness to actuator faults and external disturbances.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Hao Sheng ◽  
Xia Liu

This paper studies the problems of external disturbance and various actuator faults in a nonlinear robotic system. A composite compensation control scheme consisting of adaptive sliding mode controller and observer-based fault-tolerant controller is proposed. First, a sliding mode controller is designed to suppress the external disturbance, and an adaptive law is employed to estimate the bound of the disturbance. Next, a nonlinear observer is designed to estimate the actuator faults, and a fault-tolerant controller is obtained based on the observer. Finally, the composite compensation control scheme is obtained to simultaneously compensate the external disturbance and various actuator faults. It is proved by Lyapunov function that the disturbance compensation error and fault compensation error can converge to zero in finite time. The theoretical results are verified by simulations. Compared to the conventional fault reconstruction scheme, the proposed control scheme can compensate the disturbance while dealing with various actuator faults. The fault compensation accuracy is higher, and the fault error convergence rate is faster. Moreover, the robot can track the desired position trajectory more accurately and quickly.


Author(s):  
Haihui Long ◽  
Jiankang Zhao

In this paper, robust constrained fault-tolerant attitude controllers are proposed for flexible spacecraft subjected to external disturbance, model uncertainty, input saturation, and actuator faults. Three types of actuator faults of spacecraft, i.e. partial loss of effectiveness, stuck fault, and outage fault, are modeled explicitly. To handle these actuator faults, a significant lemma is proposed and rigorous proof is conducted at length. By introducing two e-modification parameter update laws to online estimate the unknown parameters caused by actuator faults, constrained fault-tolerant attitude controllers of flexible spacecraft are designed to accommodate these faults without the need of any prior information about these faults. The proposed controllers can achieve the disturbance attenuation in the sense of [Formula: see text] gain. The effectiveness of the proposed algorithms is assessed through numerical simulations.


Author(s):  
Min Li ◽  
Yingchun Zhang ◽  
Yunhai Geng

In this paper, the problem of fault tolerant control for spacecraft attitude tracking control system in the presence of actuator faults/failures, quantized control torque and measurement, uncertain inertial matrix and external disturbances is taken into account. The dynamical uniform quantizers are developed to quantize the signals of control torque and measurement, which can reduce the data transmission rate. In combination with the CA and FTC technique, a robust adaptive fault tolerant control scheme is proposed to cope with the effects of quantization errors in control torque and measurement, the unknown actuator faults/failures, uncertain inertial matrix and external disturbances. The developed control strategy combined with quantized control torque and measurement can guarantee the stability of overall closed-loop system and achieve satisfactory attitude tracking performance. Finally, simulation results are presented to verify the effectiveness of the proposed methods.


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