• Title/Summary/Keyword: Actuator Faults

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Fault Tolerant Control of Wind Turbine with Sensor and Actuator Faults

  • Kim, Jiyeon;Yang, Inseok;Lee, Dongik
    • Journal of Sensor Science and Technology
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    • v.22 no.1
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    • pp.28-37
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    • 2013
  • This paper presents a fault-tolerant control technique for wind turbine systems with sensor and actuator faults. The control objective is to maximize power production and minimize turbine loads by calculating a desired pitch angle within their limits. Any fault with a sensor and actuator can cause significant error in the pitch position of the corresponding blade. This problem may result in insufficient torque such that the power reference cannot be achieved. In this paper, a fault-tolerant control technique using a robust dynamic inversion observer and control allocation is employed to achieve successful pitch control despite these faults in the sensor and actuator. The observer based detection method is used to detect and isolate sensor faults by checking whether errors are larger than threshold values. In addition, the control allocation technique is adopted to tolerate actuator fault. Control allocation is one of the most commonly used fault-tolerant control techniques, especially for over-actuated systems. Further, the control allocation method can be used to achieve the power reference even in the event of blade actuator fault by redistributing the lost torque due to erroneous pitch position into non-faulty blade actuators. The effectiveness of the proposed method is demonstrated through simulations with a benchmark model of the wind turbine.

Adaptive Fault Accommodation Control for Flexible-Joint Robots (유연 관절 로봇의 적응 고장 수용 제어)

  • Yoo, Sung Jin
    • Journal of the Korean Institute of Intelligent Systems
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    • v.23 no.1
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    • pp.46-50
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    • 2013
  • This paper proposes an adaptive fault accommodation control approach for flexible-joint (FJ) robots with multiple actuator faults. It is assumed that the value and occurrence time of multiple actuator faults are unknown. An adaptive fault accommodation control scheme with prescribed performance bounds, which characterize the convergence rate and maximum overshoot of tracking errors, is designed to accommodate the actuator faults. From the Lyapunov stability theorem, it is proved that all signals of the closed-loop system are semi-globally uniformly ultimately bounded and tracking errors are preserved within prescribed performance bounds regardless of actuator faults.

Actuator Fault Estimation Method using Hexacopter Symmetry (Hexacopter의 대칭성을 이용한 구동기 고장 추정 방법)

  • Lee, Chan Hyeok;Park, Min Kee
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.7
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    • pp.519-523
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    • 2016
  • This paper proposes a method of estimating the actuator faults of a hexacopter without using encoders when one or more of six actuators do not operate normally. In the case of the hexacopter, a Pseudo-Inverse matrix is generally used to obtain the rotational speed of the actuators because the matrix that transforms the rotational speed of the actuators into the thrust and torque of the body coordinate system is not a square matrix. However, the method based on the Pseudo-Inverse matrix cannot detect the actuator faults correctly because the Pseudo-Inverse matrix is approximate. In the proposed method, the actuator faults are estimated by modifying the transform matrix using the property that the actuators of the hexacopter are symmetrical. The simulation results show the effectiveness of the proposed method when faults occur in one or more of the six actuators.

Design of Integral Observers for Unknown Actuator Faults Estimation (구동기의 미지고장추정을 위한 적분관측기 설계)

  • Ahn, P.;Lee, M.K.;Kim, J.I.
    • 전자공학회논문지 IE
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    • v.43 no.4
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    • pp.93-98
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    • 2006
  • This paper deals with the estimation of unknown actuator faults for linear dynamic systems with sensor noise. The presented method based on the integral observer permits to achieve good convergence and exact estimation of unknown faults. The validity of proposed method is established by using the simulation results which compare to the existing methods.

Design of PI Observers for Unknown Actuator Faults Estimation (구동기의 미지고장추정을 위한 PI관측기 설계)

  • Ahn, Pius;Kim, J.B.;Lee, M.K.
    • 전자공학회논문지 IE
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    • v.44 no.2
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    • pp.54-59
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    • 2007
  • This paper deals with the estimation of unknown actuator faults for linear dynamic systems with sensor noise. The presented method based on the PI(proportional-integral) observer permits to achieve good convergence and exact estimation of unknown faults. The validity of proposed method is established with simulation results and comparisons to the existing methods.

Fault Detection and Reconstruction for Descriptor Systems with Actuator and Sensor Faults

  • Yeu, Tae-Kyeong;Matsunaga, Nobutomo;Kawaji, Shigeyasu
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.2582-2587
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    • 2003
  • This paper proposes an application of sliding mode observer to the problem of fault detection and reconstruction for descriptor systems with both actuator and sensor faults. In detecting and reconstructing the faults simultaneously, first, we will consider the fault detection problem for sensor fault. The detection of sensor fault is achieved from the design of the matrix which eliminates the influence of actuator fault. Secondly, the sliding mode observer which adds the general full-order observer for descriptor system to feedforward injection map and feedforward compensation signal is designed, and through which the sensor fault is reconstructed. Finally, with the reconstructed sensor fault, and by eliminating differential term of the sensor fault, the actuator fault is detected and reconstructed.

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Fault Tolerant Control of Hexacopter for Actuator Faults using Time Delay Control Method

  • Lee, Jangho;Choi, Hyoung Sik;Shim, Hyunchul
    • International Journal of Aeronautical and Space Sciences
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    • v.17 no.1
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    • pp.54-63
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    • 2016
  • A novel attitude tacking control method using Time Delay Control (TDC) scheme is developed to provide robust controllability of a rigid hexacopter in case of single or multiple rotor faults. When the TDC scheme is developed, the rotor faults such as the abrupt and/or incipient rotor faults are considered as model uncertainties. The kinematics, modeling of rigid dynamics of hexacopter, and design of stability and controllability augmentation system (SCAS) are addressed rigorously in this paper. In order to compare the developed control scheme to a conventional control method, a nonlinear numerical simulation has been performed and the attitude tracking performance has been compared between the two methods considering the single and multiple rotor faults cases. The developed control scheme shows superior stability and robust controllability of a hexacopter that is subjected to one or multiple rotor faults and external disturbance, i.e., wind shear, gust, and turbulence.

The Design and Implementation of a Fault Diagnosis on an Electronic Throttle Control System (전자식 스로틀 제어시스템을 위한 오류 자기진단 기능 설계 및 구현)

  • Kang, Jong-Jin;Lee, Woo-Taik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.6
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    • pp.9-16
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    • 2007
  • This paper describes the design and implementation of the fault diagnosis on the Electronic Throttle Control(ETC) System. The proposed fault diagnosis consists of an input signal, actuator and a processor diagnosis. The input signal diagnosis can detect the faults of the ETC system's input signals such as the position sensor fault, source voltage fault, load current fault, and desired position fault. The actuator diagnosis is able to detect the actuator fault due to the actuator aging and an obstacle which interfere in the movement of the actuator. The processor diagnosis detects the fault which prevents the microprocessor from operating the ETC software. In order to protect the breakdown of the ETC system and assure the driving safety, appropriate reactions are also proposed according to the detected faults. The safety and reliability of the ETC system can be improved by the proposed fault diagnosis.

Design of Sliding Mode Controller Based on Adaptive Fault Diagnosis Observer for Nonlinear Continuous-Time Systems (비선형 연속 시간 시스템을 위한 적응 고장 진단 관측기 기반 슬라이딩 모드 제어기 설계)

  • Chang, Seung Jin;Choi, Yoon Ho;Park, Jin Bae
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.9
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    • pp.822-826
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    • 2013
  • In this paper, we propose an AFDO (Adaptive Fault Diagnosis Observer) and a fault tolerant controller for a class of nonlinear continuous-time system under the nonlinear abrupt actuator faults. Together with its estimation laws, the AFDO which estimates that the actuator faults is designed by using the Lyapunov analysis. Then, based on the designed AFDO, an adaptive sliding mode controller is proposed as the fault tolerant controller. Using Lyapunov stability analysis, we also prove the uniform boundedness of the state, the output and the fault estimation errors, and the asymptotic stability of the tracking error under the nonlinear time-varying faults. Finally, we illustrate the effectiveness of the proposed diagnosis method and the control scheme thorough computer simulations.

Incorporating Performance Degradation in Fault Tolerant Control System Design with Multiple Actuator Failures

  • Zhang, Youmin;Jiang, Jin;Theilliol, Didier
    • International Journal of Control, Automation, and Systems
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    • v.6 no.3
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    • pp.327-338
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    • 2008
  • A fault tolerant control system design technique has been proposed and analyzed for managing performance degradation in the presence of multiple faults in actuators. The method is based on a control structure with a model reference reconfigurable control design in an inner loop and command input adjustment in an outer loop. The reduced dynamic performance requirements in the presence of different actuator faults are accounted for through different performance reduced (degraded) reference models. The degraded steady-state performances are governed by the reduced levels of command input. The reconfigurable controller is designed on-line automatically in an explicit model reference control framework so that the dynamics of the closed-loop system follow that of the performance reduced reference model under each fault condition. The reduced command input level is determined to prevent potential actuator saturation. The proposed method has been evaluated and analyzed using an aircraft example against actuator faults subject to constraints on the magnitude and slew-rate of actuators.