scholarly journals Fault Tolerance for Active Surface System with Actuator Faults

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Danqing Zhang ◽  
Binbin Xiang ◽  
Aili Yusup ◽  
Na Wang ◽  
Guljaina Kazezkhan
Keyword(s):  
Control Method ◽  
Fault Tolerant ◽  
Active Surface ◽  
Surface Shape ◽  
Actuator Faults ◽  
Surface System ◽  
Main Reflector ◽  
And Performance ◽  
The Stability ◽  
Adjustment System

The QiTai Radio Telescope (QTT) will be equipped with the active surface adjustment system (ASAS) to correct the main reflector deformation caused by environmental loading. In order to guarantee the stability and performance of the active surface system under fault conditions, it is necessary to adopt the fault-tolerant method when actuator faults have occurred. In this paper, a fault control method based on actuator faults weighting is proposed to solve the active surface fault control problem. According to the coordinates of the adjustable points of the panels corresponding to the faulty actuators, a new paraboloid is fitted by a weighted health matrix, and the fitting surface is taken as the target to adjust the surface shape.

A finite-time H-infinite adaptive fault-tolerant controller considering time delay for flutter suppression of airfoil flutter

2019 ◽  
Vol 234 (2) ◽  
pp. 293-307
Author(s):  
Gao Ming-Zhou ◽  
Chen Xin-Yi ◽  
Han Rong ◽  
Yao Jian-Yong
Keyword(s):  
Finite Time ◽  
Control Method ◽  
Controller Design ◽  
Fault Tolerant ◽  
Linear Matrix ◽  
Control Methods ◽  
Actuator Faults ◽  
Control Delay ◽  
Modeling Uncertainties ◽  
The Stability

To suppress airfoil flutter, a lot of control methods have been proposed, such as classical control methods and optimal control methods. However, these methods did not consider the influence of actuator faults and control delay. This paper proposes a new finite-time H∞ adaptive fault-tolerant flutter controller by radial basis function neural network technology and adaptive fault-tolerant control method, taking into account actuator faults, control delay, modeling uncertainties, and external disturbances. The theoretic section of this paper is about airfoil flutter dynamic modeling and adaptive fault-tolerant controller design. Lyapunov function and linear matrix inequality are employed to prove the stability of the proposed control method of this paper. The numeral simulation section further proves the effectiveness and robustness of the proposed control algorithm of this paper.

scholarly journals Cloud-Based Fault Tolerant Control for a DC Motor System

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Xiao He ◽  
Yamei Ju ◽  
Yang Liu ◽  
Bangcheng Zhang
Keyword(s):  
Fault Diagnosis ◽  
Motor System ◽  
Control Method ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Dc Motor ◽  
Fault Estimation ◽  
Packet Dropout ◽  
Actuator Faults ◽  
The Stability

The fault tolerant control problem for a DC motor system is investigated in a cloud environment. Packet dropout phenomenon introduced by the limited-capacity communication channel is considered. Actuator faults are taken into consideration and fault diagnosis and fault tolerant control methods towards actuator faults are proposed to enhance the reliability of the whole cloud-based DC motor system. The fault diagnosis unit is then established with purpose of obtaining fault information. When the actuator fault is detected by comparing the residual signal with a predefined threshold, a residual matching approach is utilized to locate the fault. The fault can be further estimated by a least-squares filter. Based on the fault estimation, a fault tolerant controller is designed to guarantee the stability as well as the control performance of the DC motor system. Simulation result on a DC motor system shows the efficiency of the fault tolerant control method proposed in this paper.

Adaptive Sliding Mode Fault-Tolerant Control for an Unmanned Aerial Vehicle

2017 ◽  
Vol 05 (04) ◽  
pp. 209-221 ◽  
Author(s):  
Ban Wang ◽  
Youmin Zhang
Keyword(s):  
System Performance ◽  
Control Method ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Actuator Faults ◽  
Control Effort ◽  
Discontinuous Control ◽  
Control Effectiveness ◽  
System Uncertainties ◽  
Chattering Effect

Sliding mode control (SMC) is known as a robust control method to maintain system performance and keep it insensitive to system uncertainties. To achieve this objective, the knowledge of the uncertainty bound is usually needed, but sometimes it could be a hard task. Hence, the adaptive technology is introduced to be synthesized with SMC. In this paper, a novel adaptive SMC (ASMC) scheme is proposed to accommodate system uncertainties caused by actuator faults. An integral sliding mode controller is used as the baseline controller. When actuator faults occur, there is no need to know the exact bound of the uncertainties in control effectiveness matrix. The post-fault control effectiveness matrix can be estimated by the proposed adaptive control scheme, and the control inputs will be changed accordingly. In such a way, the robustness of the controller to actuator faults is improved. With the help of adaptive change of both continuous and discontinuous control parts, a minimum value of the discontinuous control gain can be guaranteed. In this case, the resulting control effort is reduced accordingly to avoid control chattering effect. Owing to the minimized control effort to accommodate uncertainties compared to the conventional SMC, the proposed ASMC can still maintain the system performance when severer faults occur. The effectiveness of the developed algorithm is demonstrated by the simulation results based on an unmanned quadrotor helicopter under various faulty conditions.

scholarly journals A hybrid fault-tolerant control strategy for four-wheel independent drive vehicles

2021 ◽  
Vol 13 (9) ◽  
pp. 168781402110454
Author(s):  
Ruinan Chen ◽  
Jian Ou
Keyword(s):  
Real Time ◽  
Control Strategy ◽  
High Performance ◽  
Control Method ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Fault Tolerant Control ◽  
The Stability ◽  
Model Reference Adaptive ◽  
Observation Results

In this paper, a hybrid fault-tolerant control strategy is putted forward to improve the stability of the four-wheel independent drive (4WID) electric vehicle with motor failures. To improve the handling performance of the vehicle with in-wheel motor failures, the faults of in-wheel motors are analyzed and modeled. Then, a model reference adaptive fault observer was designed to observe the faults in real-time. Based on the observation results, there are designed a model predictive control (MPC) based high-performance active fault-tolerant control (AFTC) strategy and a sliding mode control based high-robust passive fault-tolerant control (PFTC) strategy. However, the fault observation results may not always be accurately. For this circumstance, a hybrid fault-tolerant control strategy was designed to make the control method find a balance between optimality and robustness. Finally, a series of simulations are conducted on a hardware-in-loop (HIL) real-time simulator, the simulation results show that the control strategy designed in this paper is effectiveness.

scholarly journals L1 Adaptive for Aircraft Lateral Fault Tolerant Control with Actuator Failure

2019 ◽  
Vol 37 (5) ◽  
pp. 935-942
Author(s):  
Yan Zhou ◽  
Huiying Liu ◽  
Jing Li
Keyword(s):  
Control Method ◽  
Fault Tolerant ◽  
Adaptive Controller ◽  
Actuator Failure ◽  
Bounded Control ◽  
L1 Adaptive Control ◽  
Unmatched Uncertainties ◽  
Fault Mode ◽  
The Stability ◽  
Multiplicative Fault

When aircraft is laterally controlled, actuator failure may cause matched/unmatched uncertainties. In order to deal with the uncertainty, a fault-tolerant controller is designed by using L1 adaptive control method. An aircraft lateral model was established by considering faults and disturbances, the effects of the uncertainty and interference were counteracted by using L1 adaptive controller in order to ensure the rapid adaptation and robustness, and then the stability and transient performance of the closed-loop system were proven through Lyapunov method. In the case of multiplicative fault, additive fault and stuck fault, the uncertainties of model parameter were added to simulate simultaneously. Simulation results showed that the present control method in both single-fault mode and hybrid-failure mode could ensure the uniform bounded control signal and parameter estimation, effectively eliminates the effect of the faults and had the good fault tolerance and robustness.

scholarly journals Sardinia Radio Telescope: General Description, Technical Commissioning and First Light

2015 ◽  
Vol 04 (03n04) ◽  
pp. 1550008 ◽  
Author(s):  
P. Bolli ◽  
A. Orlati ◽  
L. Stringhetti ◽  
A. Orfei ◽  
S. Righini ◽  
...  
Keyword(s):  
Radio Telescope ◽  
Active Surface ◽  
Total Power ◽  
General Description ◽  
Operational Capabilities ◽  
Pointing Accuracy ◽  
Main Reflector ◽  
And Performance ◽  
The Given ◽  
Good Agreement

In the period 2012 June–2013 October, the Sardinia Radio Telescope (SRT) went through the technical commissioning phase. The characterization involved three first-light receivers, ranging in frequency between 300[Formula: see text]MHz and 26[Formula: see text]GHz, connected to a Total Power back-end. It also tested and employed the telescope active surface installed in the main reflector of the antenna. The instrument status and performance proved to be in good agreement with the expectations in terms of surface panels alignment (at present 300[Formula: see text][Formula: see text]m[Formula: see text]rms to be improved with microwave holography), gain ([Formula: see text]0.6[Formula: see text]K/Jy in the given frequency range), pointing accuracy (5 arcsec at 22[Formula: see text]GHz) and overall single-dish operational capabilities. Unresolved issues include the commissioning of the receiver centered at 350[Formula: see text]MHz, which was compromised by several radio frequency interferences, and a lower-than-expected aperture efficiency for the 22-GHz receiver when pointing at low elevations. Nevertheless, the SRT, at present completing its Astronomical Validation phase, is positively approaching its opening to the scientific community.

scholarly journals Fault Diagnosis and Fault-Tolerant Control Scheme for Quadcopter UAVs with a Total Loss of Actuator

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1139 ◽  
Author(s):  
Ngoc Nguyen ◽  
Sung Hong
Keyword(s):  
Fault Diagnosis ◽  
Active Fault ◽  
Control Method ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Fault Tolerant Control ◽  
Total Loss ◽  
Actuator Faults ◽  
Control Scheme ◽  
Robust Adaptive

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.

Distributed fault-tolerant formation control for multiple unmanned aerial vehicles under actuator fault and intermittent communication interrupt

2021 ◽  
pp. 095965182097908
Author(s):  
Bing Han ◽  
Ju Jiang ◽  
Chaojun Yu
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Formation Control ◽  
Fault Tolerant ◽  
Input Saturation ◽  
Actuator Faults ◽  
Aerial Vehicles ◽  
Multiple Unmanned Aerial Vehicles ◽  
The Stability ◽  
Intermittent Communication ◽  
Formation System

This article develops a distributed adaptive fault-tolerant formation control scheme for the multiple unmanned aerial vehicles to counteract actuator faults and intermittent communication interrupt, where the issues on control input saturation and mismatched uncertainties are also addressed. The discontinuous communication protocol technique is exploited to achieve the stability of the formation system, if the conditions of dwell time and the rate of communication are satisfied. On the basis of the local information of neighboring unmanned aerial vehicles, a novel distributed adaptive mechanism is designed to estimate the bounds of actuator faults and uncertainties, where the input saturation is explicitly taken into consideration. The stability of the whole formation system under the designed fault-tolerant formation control strategy is analyzed using the Lyapunov approach. Finally, simulation results are presented to illustrate the effectiveness of the proposed scheme.

scholarly journals Fault-Tolerant Aircraft Control Based on Self-Constructing Fuzzy Neural Network for Quadcopter

2021 ◽  
Vol 15 (1) ◽  
pp. 109-122
Author(s):  
Dejie Li ◽  
◽  
Pu Yang ◽  
Zhangxi Liu ◽  
Zixin Wang ◽  
...  
Keyword(s):  
Neural Network ◽  
Fuzzy Neural Network ◽  
Control Method ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Failure Model ◽  
Aircraft Control ◽  
Actuator Failure ◽  
Fuzzy Neural ◽  
The Stability

This paper proposes a fault-tolerant aircraft control method based on a self-constructed fuzzy neural network for quadcopters with multiple actuator faults. We first introduce the actuator failure model and the model uncertainty. Subsequently, we establish a framework for a self-constructed fuzzy neural network observer with an adaptive rate to obtain the estimated value of the nonlinear term of the module uncertainty. We also design a multivariable sliding mode fault-tolerant controller to ensure the stability of the aircraft under this fault condition. Finally, we conduct experiments using the Pixhawk 4 flight controller installed on the QBall-X4 UAV experimental platform, such that the use of the flight controller’s fault coprocessor and redundant sensor design reduces the crash that occurs during the debugging of the control algorithm. Compared to the existing intelligent fault-tolerant control technology, our proposed method employs fewer fuzzy rules, and the number of these rules can be adaptively adjusted when the system model changes. In the experimental test, the aircraft was still able to fly stably under multi-actuator failure and interference conditions, thereby proving the stability of the proposed controller.

Adaptive anti-saturation fault-tolerant control of hypersonic vehicle with actuator faults

2018 ◽  
Vol 233 (6) ◽  
pp. 2066-2083
Author(s):  
Jing-guang Sun ◽  
Shen-Min Song ◽  
Peng-Li ◽  
Guan-qun Wu
Keyword(s):  
Finite Time ◽  
Control Method ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Input Saturation ◽  
Reference Signal ◽  
Fault Tolerant Control ◽  
Hypersonic Vehicle ◽  
Actuator Faults ◽  
The Impact

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.

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