scholarly journals Systematic Fault Tolerant Control Based on Adaptive Thau Observer Estimation for Quadrotor Uavs

2015 ◽  
Vol 25 (1) ◽  
pp. 159-174 ◽  
Author(s):  
Zhaohui Cen ◽  
Hassan Noura ◽  
Younes Al Younes
Keyword(s):  
Normal Control ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Condition Based Maintenance ◽  
Fault Estimation ◽  
Time Varying ◽  
Fault Severity ◽  
Quadrotor Uavs ◽  
Severity Levels

Abstract A systematic fault tolerant control (FTC) scheme based on fault estimation for a quadrotor actuator, which integrates normal control, active and passive FTC and fault parking is proposed in this paper. Firstly, an adaptive Thau observer (ATO) is presented to estimate the quadrotor rotor fault magnitudes, and then faults with different magnitudes and time-varying natures are rated into corresponding fault severity levels based on the pre-defined fault-tolerant boundaries. Secondly, a systematic FTC strategy which can coordinate various FTC methods is designed to compensate for failures depending on the fault types and severity levels. Unlike former stand-alone passive FTC or active FTC, our proposed FTC scheme can compensate for faults in a way of condition-based maintenance (CBM), and especially consider the fatal failures that traditional FTC techniques cannot accommodate to avoid the crashing of UAVs. Finally, various simulations are carried out to show the performance and effectiveness of the proposed method.

scholarly journals Active Fault-Tolerant Control of a Quadcopter against Time-Varying Actuator Faults and Saturations Using Sliding Mode Backstepping Approach

2019 ◽  
Vol 9 (19) ◽  
pp. 4010 ◽  
Author(s):  
Ngoc Phi Nguyen ◽  
Sung Kyung Hong
Keyword(s):  
Fault Diagnosis ◽  
Active Fault ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Fault Tolerant Control ◽  
Lyapunov Theory ◽  
Fault Estimation ◽  
Time Varying ◽  
Actuator Faults ◽  
Active Fault Tolerant Control

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.

Fuzzy Fault Tolerant Control of a Bacterial Growth Process Using a Multiple Lyapunov Function

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Abdelmounaim Khallouq ◽  
Asma Karama ◽  
Mohamed Abyad
Keyword(s):  
Lyapunov Function ◽  
Bacterial Growth ◽  
Growth Process ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Fault Estimation ◽  
Time Varying ◽  
Actuator Fault ◽  
Actuator Faults ◽  
Multiple Lyapunov Function

Abstract This paper presents the problem of actuator fault estimation and fault-tolerant control (FTC) of a biological process using Takagi–Sugeno fuzzy formulation. The goal is to ensure the desired outputs tracking even if the time-varying actuator faults occur. We propose to use a proportional multi-integral (PMI) observer to estimate both the time-varying actuator faults and the state of system. The reconstructed faults are used to reconfigure the nominal controller. As a nominal control, we use a fuzzy linear quadratic integral (LQI) law. To ensure the global asymptotic convergence of the PMI observer and to improve the compensation speed of faults, we propose to use the multiple Lyapunov function by introducing a convergence rate. Sufficient conditions in terms of linear matrix inequalities (LMIs) are developed. The obtained results show that, the proposed approach is successfully applied to the problem of actuator fault-tolerant control of a bacterial growth process.

scholarly journals Fault tolerant control for nonlinear systems using sliding mode and adaptive neural network estimator

2019 ◽  
Vol 24 (15) ◽  
pp. 11535-11544 ◽  
Author(s):  
Haiying Qi ◽  
Yiran Shi ◽  
Shoutao Li ◽  
Yantao Tian ◽  
Ding-Li Yu ◽  
...  
Keyword(s):  
Neural Network ◽  
Nonlinear Systems ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Fault Tolerant Control ◽  
System Stability ◽  
Fault Estimation ◽  
Time Varying ◽  
Change Rate ◽  
The Impact

AbstractThis paper proposes a new fault tolerant control scheme for a class of nonlinear systems including robotic systems and aeronautical systems. In this method, a sliding mode control is applied to maintain system stability under the post-fault dynamics. A neural network is used as on-line estimator to reconstruct the change rate of the fault and compensate for the impact of the fault on the system performance. The control law and the neural network learning algorithms are derived using the Lyapunov method, so that the neural estimator is guaranteed to converge to the fault change rate, while the entire closed-loop system stability and tracking control is guaranteed. Compared with the existing methods, the proposed method achieved fault tolerant control for time-varying fault, rather than just constant fault. This greatly expands the industrial applications of the developed method to enhance system reliability. The main contribution and novelty of the developed method is that the system stability is guaranteed and the fault estimation is also guaranteed for convergence when the system subject to a time-varying fault. A simulation example is used to demonstrate the design procedure and the effectiveness of the method. The simulation results demonstrated that the post-fault is stable and the performance is maintained.

scholarly journals Fault-Tolerant Control Strategy with Asymmetric Phase Currents for Single to Four-Phase Open-Circuit Faults of Six-Phase PMSM

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3163
Author(s):  
Chen Huang ◽  
Lidan Zhou ◽  
Zujia Cao ◽  
Gang Yao
Keyword(s):  
Working Conditions ◽  
Control Strategy ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Open Circuit ◽  
Time Varying ◽  
Electromagnetic Torque ◽  
Control Loops ◽  
Phase Current ◽  
Multi Phase

Multi-phase motors and generators are regarded with great fault tolerance capability, especially on open-circuit faults. Various mathematics analytical methods are applied for their fault control. In this paper, a fault-tolerant control strategy with asymmetric phase current for the open-circuit faults with arbitrary phases in the six-phase PMSM (six-phase permanent magnetic synchronous motor, 6P-PMSM) system, is proposed for better electrical and dynamical performance of the machine. An innovative mathematical model for PMSM under one to four-phase-open circuit faults are established considering the asymmetry of the machine. Combining with time-varying relations in machines’ working conditions, targeted decoupling transformation matrixes of every kind of open-circuit faults are settled by voltage equations under different faults. Modified control strategy with a connection between the neutral point and the inverter’s DC side is presented, which aims at increasing the system redundancy and reducing the amplitude of phase currents. Besides, improved control loops with two layers are put forward as well, with which the PMSM system acquires fewer harmonics in phase current and smoother electromagnetic torque. Simulation and experimental results of open-circuit faults are provided for verification of the theoretical analysis.

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