Fault-tolerant control of hypersonic vehicles based on fast fault observer under actuator gain loss fault or stuck fault

2020 ◽  
Vol 124 (1278) ◽  
pp. 1190-1207
Author(s):  
P. Zhu ◽  
J. Jiang ◽  
C. Yu

ABSTRACTThis paper proposes a fault-tolerant control (FTC) method based on fast fault observer (FFO) to solve the problem of actuator gain loss fault and stuck fault for hypersonic vehicles. Firstly, an input-output feedback linearisation model is presented that considers parametric uncertainties, control input saturation, disturbances and actuator faults. Secondly, the above factors are defined as an integrated fault item, and an improved fast fault observer is designed to estimate the integrated fault in real time. Finally, the fault-tolerant controller is constructed based on the sliding mode and fault estimation. In case of unknown faults, the effects of gain loss fault or stuck fault happen on elevators and the engine can be quickly processed, Also, the asymptotically stable tracking of the flight output reference command is completed to achieve fault-tolerant control. The final simulation experiment verifies the effectiveness of the proposed method.

2019 ◽  
Vol 9 (19) ◽  
pp. 4010 ◽  
Author(s):  
Ngoc Phi Nguyen ◽  
Sung Kyung Hong

Fault-tolerant control is becoming an interesting topic because of its reliability and safety. This paper reports an active fault-tolerant control method for a quadcopter unmanned aerial vehicle (UAV) to handle actuator faults, disturbances, and input constraints. A robust fault diagnosis based on the H ∞ scheme was designed to estimate the magnitude of a time-varying fault in the presence of disturbances with unknown upper bounds. Once the fault estimation was complete, a fault-tolerant control scheme was proposed for the attitude system, using adaptive sliding mode backstepping control to accommodate the actuator faults, despite actuator saturation limitation and disturbances. The Lyapunov theory was applied to prove the robustness and stability of the closed-loop system under faulty operation. Simulation results show the effectiveness of the fault diagnosis scheme and proposed controller for handling actuator faults.


2021 ◽  
Vol 11 (16) ◽  
pp. 7236
Author(s):  
Xiangxiang Su ◽  
Benxian Xiao

For the problem of actuator-integrated fault estimation (FE) and fault tolerant control (FTC) for the electric power steering (EPS) system of a forklift, firstly, a dynamic model of a forklift EPS system with actuator faults was established; then, an integrated FE and FTC design was proposed. The nonlinear unknown input observer (NUIO) was proposed to estimate the system states and actuator faults, and an adaptive sliding mode FTC system was constructed based on it. The gain of the observer and controller is obtained by H∞ optimization and one-step linear matrix inequality (LMI) formula operation in order to realize the overall optimal design of an FTC system. Finally, the experimental results show that when actuator failure occurs, the proposed integrated FE and FTC were more accurate than the decentralized design to estimate the system states and the actuator faults. The proposed fault-tolerant controller can more effectively restore the power assist performance of the steering power motor in case of failure and effectively ensure the safety and reliability of the forklift EPS system.


Author(s):  
Jing-guang Sun ◽  
Shen-Min Song ◽  
Peng-Li ◽  
Guan-qun Wu

In this paper, related researches and analyses are conducted for the tracking problem of the hypersonic vehicle subject to external disturbances, actuator faults, and input saturation. Firstly, to achieve automatic adjustment of control gains and deal with the impact of dynamic failures of system without requiring prior knowledge of the fault, a new modified fast nonsingular terminal sliding manifold is proposed, and a fast adaptive finite time fault-tolerant controller is provided combining the adaptive control method and terminal sliding mode. Then, a fast adaptive finite time anti-saturation fault-tolerant controller is presented to further solve the problem of input saturation, under which both of the velocity and altitude can track respective reference signal with the actuator input constraint. Finally, the closed-loop stability under the proposed two adaptive fault-tolerant control schemes is analyzed, and numerical simulations of longitudinal model of the hypersonic vehicle are demonstrated to further confirm the effectiveness of the proposed approach.


Author(s):  
Salman Ijaz ◽  
Mirza T Hamayun ◽  
Lin Yan ◽  
Cun Shi

The research about the dissimilar redundant actuation system has indicated the potential fault-tolerant capability in modern aircraft. This paper proposed a new design methodology to achieve fault-tolerant control of an aircraft equipped with dissimilar actuators and is suffered from vertical tail damage. The proposed design is based on the concept of online control allocation to redistribute the control signals among healthy actuators and integral sliding mode controller is designed to achieve the closed-loop stability in the presence of both component and actuator faults. To cope with severe damage condition, the aircraft is equipped with dissimilar actuators (hydraulic and electrohydraulic actuators). In this paper, the performance degradation due to slower dynamics of electrohydraulic actuator is taken in account. Therefore, the feed-forward compensator is designed for electrohydraulic actuator based on fractional-order control strategy. In case of failure of hydraulic actuator subject to severe damage of vertical tail, an active switching mechanism is developed based on the information of fault estimation unit. Additionally, a severe type of actuator failure so-called actuator saturation or actuator lock in place is also taken into account in this work. The proposed strategy is compared with the existing control strategies in the literature. Simulation results indicate the dominant performance of the proposed scheme. Moreover, the proposed controller is found robust with a certain level of mismatch between the actuator effectiveness level and its estimate.


Author(s):  
Bingqian Li ◽  
Wenhan Dong ◽  
Xiaoshan Ma

In this paper, a backstepping fault-tolerant control based on sliding-mode observer is proposed for the unmanned thrust-vectoring aircraft (UTVA) control. First, the UTVA model with the uncertainty, control surface damage and actuator faults is described, which is divided into fast loop and slow loop. Next, the cascade observers including a high-order SMO and the discontinuous projection adaptive law are proposed to estimate the states with compensating the uncertainty and control surface damage, and the sliding-mode observer is designed to identify actuator faults and estimate fault parameters. Then, the backstepping fault-tolerant control combining the estimation of states and fault parameters is proposed to achieve the global fault-tolerant control, which compensates the uncertainty, control surface damage and actuator faults. Finally, simulation results are given to demonstrate the effectiveness for UTVA.


2014 ◽  
Vol 635-637 ◽  
pp. 1199-1202 ◽  
Author(s):  
Zheng Gao Hu ◽  
Guo Rong Zhao ◽  
Da Wang Zhou

For the chattering problem in the traditional sliding mode observer-based fault estimation, a second order sliding mode observer based on the Super-twisting algorithm was proposed. In order to avoid the cumbersome process of proving the stability of the Super-twisting algorithm, a Lyapunov function was adopted. An active fault tolerant control law was designed based on the fault estimation. Finally, simulation show the effectiveness of the proposed approach.


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