scholarly journals Robust Adaptive Fault-Tolerant Control of Stochastic Systems with Modeling Uncertainties and Actuator Failures

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Wenchuan Cai ◽  
Lingling Fan ◽  
Yongduan Song

This paper deals with the problem of fault-tolerant control (FTC) of uncertain stochastic systems subject to modeling uncertainties and actuator failures. A robust adaptive fault-tolerant controller design method based on stochastic Lyapunov theory is developed to accommodate the negative impact on system performance arising from uncertain system parameters and external disturbances as well as actuation faults. There is no need for on-line fault detection and diagnosis (FDD) unit in the proposed FTC scheme, which not only simplifies the design process but also makes the implementation inexpensive. Numerical examples are provided to validate and illustrate the benefits of the proposed control method.

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 95 ◽  
Author(s):  
Ngoc Phi Nguyen ◽  
Sung Kyung Hong

In this paper, a fault-tolerant control method is proposed for quadcopter unmanned aerial vehicles (UAV) to account for system uncertainties and actuator faults. A mathematical model of the quadcopter UAV is first introduced when faults occur in actuators. A normal adaptive sliding mode control (NASMC) approach is proposed as a baseline controller to handle the chattering problem and system uncertainties, which does not require information of the upper bound. To improve the performance of the NASMC scheme, radial basis function neural networks are combined with an adaptive scheme to make a quick compensation in presence of system uncertainties and actuator faults. The Lyapunov theory is applied to verify the stability of the proposed methods. The effectiveness of modified ASMC algorithm is compared with that of NASMC using numerical examples under different faulty conditions.


2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Liang Zheng ◽  
Xuelian Dong ◽  
Qian Luo ◽  
Menglan Zeng ◽  
Xinping Yang ◽  
...  

In this paper, an adaptive sliding mode fault tolerant control (ASMFTC) approach is proposed for a class of nonlinear systems with actuator fault, uncertainty, and external disturbance. Specifically, first, a novel observer is proposed to estimate the state, actuator fault, and external disturbance. Then, by utilising the observed information, a novel output sliding mode observer is constructed. In the control method, an adaptive law and two compensators are designed to attenuate the unknown estimation errors, actuator fault, and disturbance. Furthermore, the reaching ability of the sliding motion is analysed and the H-infinite performance is introduced to ensure the robustness of the system. Finally, a flexible single joint manipulator system and a two-cart system are used to verify the effectiveness of the proposed method.


Author(s):  
Shreekant Gayaka ◽  
Bin Yao

In this paper we present an output feedback based Adaptive Robust Fault Tolerant Control (ARFTC) strategy to solve the problem of output tracking in presence of actuator failures, disturbances and modeling uncertainties for a class of nonlinear systems. The class of faults addressed here include stuck actuators, actuator loss of efficiency or a combination of the two. We assume no a priori information regarding the instant of failure, failure pattern or fault size. The ARFTC combines the robustness of sliding mode controllers with the online learning capabilities of adaptive control to accommodate sudden changes in system parameters due to actuator faults. Comparative simulation studies are carried out on a nonlinear hypersonic aircraft model, which shows the effectiveness of the proposed scheme over back-stepping based robust adaptive fault-tolerant control.


Author(s):  
Haiyang Zhu ◽  
Yansheng Wu ◽  
Yi Rong ◽  
Xudong Qin ◽  
Yu Chen

To tolerate the limited faults such as thrust decline or actuator jamming of launch vehicles, an adaptive fault-tolerant control method based on radial basis function neural network (RBFNN) is proposed in this paper. The method is based on a limited faults dynamics model, and the baseline controller is designed based on the pole placement, using RBFNN to online identify and compensate the fault parameters and uncertain disturbances in the model. Then an adaptive fault-tolerant control law is designed based on Lyapunov theory. The simulation results show that the proposed adaptive control method can effectively ensure the attitude stability as well as control accuracy under the limited faults of launch vehicles, compared with the traditional PD control method.


Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1139 ◽  
Author(s):  
Ngoc Nguyen ◽  
Sung Hong

Fault-tolerant control has drawn attention in recent years owning to its reliability and safe flight during missions. In this article, an active fault-tolerant control method is proposed to control a quadcopter in the presence of actuator faults and disturbances. Firstly, the dynamics of the quadcopter are presented. Secondly, a robust adaptive sliding mode Thau observer is presented to estimate the time-varying magnitudes of actuator faults. Thirdly, a fault-tolerant control scheme based on sliding mode control and reconfiguration technique is designed to maintain the quadcopter at the desired position despite the presence of faults. Unlike previous studies, the proposed method aims to integrate the fault diagnosis and a fault-tolerant control scheme into a single unit with total loss of actuator. Simulation results illustrate the efficiency of the suggested algorithm.


2014 ◽  
Vol 556-562 ◽  
pp. 2452-2457
Author(s):  
Wan Qing Xiang ◽  
Wei Ao ◽  
Yi Yuan Chen

This paper proposed a fault-tolerant control (FTC) for nonlinear control-affine uncertain MIMO systems. The proposed controller is no need for on-line fault detection and diagnosis unit, and inexpensive to compute. An adaptive FTC designed method based on Lyapunov-like approach is developed to overcome the affect of parameter uncertainties, matched and mismatched disturbance, and actuator failures. And the theoretical analysis demonstrates that asymptotical tracking error convergence would be guaranteed by the controller. Numerical simulations are provided to validate and illustrate the benefits of the proposed control scheme.


Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4721 ◽  
Author(s):  
Nguyen ◽  
Mung ◽  
Hong

In this paper, fault detection and fault-tolerant control strategies are proposed to handle the issues of both actuator faults and disturbances in a hexacopter. A dynamic model of a hexacopter is first derived to develop a model-based fault detection system. Secondly, the altitude control based on a sliding mode and disturbance observer is presented to tackle the disturbance issue. Then, a nonlinear Thau observer is applied to estimate the states of a hexacopter and to generate the residuals. Using a fault detection unit, the motor failure is isolated to address the one or two actuator faults. Finally, experimental results are tested on a DJI F550 hexacopter platform and Pixhawk2 flight controller to verify the effectiveness of the proposed approach. Unlike previous studies, this work can integrate fault detection and fault-tolerant control design as a single unit. Moreover, the developed fault detection and fault-tolerant control method can handle up to two actuator failures in presence of disturbances.


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