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IEEE International Workshop on Imaging Systems and Techniques (IST)

作者： Yang Pei Yanbin Xu Feng Dong Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin P.R. China

Regularization methods are widely used in dealing with the ill-posed inverse problem of electrical resistance tomography (ERT), especially the Tikhonov method. A proper choice of regularization parameter is crucial to produce an efficient regularization solution. As a regularization parameter choice method, L-curve method is popular for its simpleness and intuition. However there is no guarantee that the method can always determine a proper parameter for all situations of ERT. The investigation on those failed situations shows that a new corner point often appears on the curve and the parameter corresponding to the new corner point can obtain a better solution than the one corresponding to the traditional global corner point. Therefore a modified L-curve method is proposed based on the new corner point. Moreover two strategies are provided to implement the modified method: one computes the new corner point by means of the second-order differential of L-curve, and another computes the new corner point with the help of the curvature of L-curve. The modified L-curve method is verified by numerical simulations of some typical distributions in ERT. And the results indicate that the modified method can achieve an efficient solution and implement the image reconstruction where the traditional L-curve method cannot. The modified L-curve method extends the application of L-curve in the field of choosing regularization parameter and can also be applied in other kinds of tomography.

关键词： Image reconstruction Conductivity Inverse problems Tomography Resistance Jacobian matrices Voltage measurement

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FOC for loss minimization of induction motor using SVM

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Metallurgical and Mining Industry 2015年第4期7卷 79-84页

作者： Xie, Fang Wang, Qunjing School of Electrical Engineering and Automation Anhui University Hefei Anhui China Anhui Province Laboratory of Electrical Economize and Safety Anhui University Anhui China National Engineering Laboratory of Energy-Saving Motor and Control Technology Anhui University Hefei Anhui China

Field oriented control (FOC) can provide an ability to rapidly and accurately control torque and speed of induction motors (IM). However, at lower than rated loads, which is a condition that many machines experience for significant portion of their service life, the efficiency is greatly reduced. This paper describes the use of supported vector machine (SVM) to optimize the efficiency of IM drive. The approach eliminates the need of accurate math model and large computation complexity in traditional loss model controller (LMC). The new efficiency optimizing controller adjusts a magnetizing current component in vector controlled drives, which ensures a minimum loss to improve efficiency of the drive system especially when driving light load. The performance of the proposed drive is demonstrated through simulation in MATLAB/SIMULINK and compared the same with traditional FOC without LMC. Results show that there is considerable loss reduction and improvement in efficiency under light load condition using the method. © Metallurgical and Mining Industry, 2015.

关键词： Vector control (Electric machinery)

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Diagnosis of wind turbine rotor system

Diagnosis of wind turbine rotor system

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American control Conference

作者： Henrik Niemann Mahmood Mirzaei Lars Christian Henriksen Niels Kjolstad Poulsen Dept. of Electrical Engineering Automation and Control Build. 326 Technical University of Denmark DK-2800 Kgs. Lyngby Denmark Dept. of wind energy Technical University of Denmark DK-2800 Kgs. Lyngby Denmark AF Consult Lyskaer 3F 2730 Herlev Denmark Dept. of Applied Mathematics and Computer Science Technical University of Denmark DK-2800 Kgs. Lyngby Denmark

ISBN: (纸本)9781467386838

This paper describes a model free method for monitoring and fault diagnosis of the elements in a rotor system for a wind turbine. The diagnosis as well as the monitoring is done without using any model of the wind turbine and the applied controller or a description of the wind profile. The method is based on available standard sensors on wind turbines. The method can be used both on-line as well as off-line. Faults or changes in the rotor system will result in asymmetries, which can be monitored and diagnosed. This can be done by using the multi-blade coordinate transformation. Changes in the rotor system that can be diagnosed and monitored are: actuator faults, sensor faults and internal blade changes as e.g. change in mass of a blade.

关键词： Wind turbines Monitoring Sensors Rotors Fault diagnosis Blades Aerodynamics

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Active Disturbance Rejection control for Nonlinear Two-tank Liquid Level Cascade Systems with Model Uncertainties

Active Disturbance Rejection Control for Nonlinear Two-tank ...

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The Society of Instrument and control Engineers Annual Conference 2015

作者： Lijun Wang Fen Zhang Qing Li Yixin Yin Qing Zheng Yumeng Zhang School of Automation & Electrical Engineering University of Science and Technology Beijing Key Laboratory of Advanced Control of Iron and Steel Process (Ministry of Education) University of Science and Technology Beijing Department of Electrical and Computer Engineering Gannon University

Due to the nonlinearities, model uncertainties and disturbances of the two-tank liquid level cascade system,active disturbance rejection controller(ADRC) solution was developed. First, a nonlinear mechanism model and its linearized model were built based on the theories of fluid dynamics for the system. Second, first-order linear ADRCs for the outer loop of the two cascade systems with an unknown order were designed, respectively. With a simple integrator as the normalized type of the feedback system, other parts of dynamic system which are different from the normalized type are treated as the total disturbances. The disturbances were estimated by the second-order linear extended state observer and compensated in the control law. Then the system, with nonlinearities, uncertainties and disturbances, is reduced to only a linear integrator. In comparison with the traditional PI controller, simulation results show that both the proposed ADRCs have better robustness and adaptability against model uncertainties.

关键词： Two-tank systems,nonlinear systems,uncertain systems,cascade systems,active disturbance rejection control

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ISS Properties of Sliding-Mode controllers for Systems with Matched and Unmatched Disturbances

ISS Properties of Sliding-Mode Controllers for Systems with ...

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European control Conference

作者： Andrea Aparicio Martinez Fernando Castanos Leonid Fridman Electrical Engineering PhD Program of the Faculty of Engineering Universidad Nacional Autonoma de Mexico Departamento de Control Automatico Cinvestav IPN Faculty of Engineering Universidad Nacional Autonoma de Mexico

ISBN: (纸本)9781467371605

In this paper we present a controller that achieves global input-to-state stability for a linear system of arbitrary relative degree, subjected to matched and unmatched disturbances. This controller combines the properties of a discontinuous term, and a linear one, enforcing a conventional sliding mode using only partial state information. A direct and simple way of choosing the gains for this controller is also provided.

关键词： Convergence Upper bound Backstepping Trajectory Linear systems Asymptotic stability

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Optimal Microgrid Energy Management Integrating Intermittent Renewable Energy and Stochastic Load

Optimal Microgrid Energy Management Integrating Intermittent...

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2015 IEEE Advanced Information Technology,Electronic and automation control Conference(IAEAC 2015)

作者： Ying Ji Jianhui Wang Shijie Yan Wenzhong Gao Hepeng Li College of Information Science and Engineering Northeastern University Department of Electrical and Computer Engineering University of Denver Lab.of Networked Control Systems Shenyang Institute of AutomationChinese Academy of Sciences

ISBN: (纸本)9781479919819

In this paper,we focus on energy management of distributed generators(DGs) and energy storage system(ESS) in microgrids(MG) considering uncertainties in renewable energy and load *** MG energy management problem is formulated as a two-stage stochastic programming model based on optimization ***,the optimization model is decomposed into a mixed integer quadratic programming problem by using discrete stochastic scenarios to approximate the continuous random variables.A Scenarios generation approach based on time-homogeneous Markov chain model is proposed to generate simulated time-series of renewable energy generation and load ***,the proposed stochastic programming model is tested in a typical LV network and solved by Matlab optimization *** simulation results show that the proposed stochastic programming model has a better performance to obtain robust scheduling solutions and lower the operating cost compared to the deterministic optimization modeling methods.

关键词： microgrid EMS Markov chain stochastic optimization

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Enhanced trajectory linearization control based advanced guidance and control for hypersonic reentry vehicle with multiple disturbances

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Aerospace Science and Technology 2015年 46卷 523-536页

作者： Xingling Shao Honglun Wang HuiPing Zhang School of Automation Science and Electrical Engineering Beihang University Beijing 100191 China Science and Technology on Aircraft Control Laboratory Beihang University Beijing 100191 China School of Automation Beijing Institute of Technology Beijing 100081 China Beijing Aerospace Automatic Control Institute Beijing 100854 China

In this paper, the guidance and control problem for hypersonic reentry vehicle (HRV) in the presence of control constraints and multiple disturbances is handled based on unified enhanced trajectory linearization control (TLC) framework under reference-tracking methodology. First, based on the nominal trajectory and open-loop command generated by Gauss pseudo-spectral method (GPM), a time-varying feedback guidance law with integral action is synthesized to stabilize the tracking error dynamics along the nominal trajectory under the framework of TLC. Second, to improve the robustness of attitude and angular rate loop, variations of various aerodynamic coefficients and external disturbances are considered as lumped uncertainties, reduced-order linear extended state observers (LESO) with given model information are constructed to estimate the lumped uncertainties in each loop, respectively. In addition, comparisons between the estimation efficiency of LESO and reduced-order LESO are carried out. Then augmented with the disturbance estimates and TLC control law, tracking errors of the rotational dynamics can be actively rejected without sacrificing nominal performances. More importantly, fewer control consumption and smooth transient performances are achieved by using nonlinear tracking differentiator (TD) in attitude loop. The stability of the resulting closed-loop system is well established based on Lyapunov stability theory . Finally, the effectiveness of the proposed advanced guidance and control strategy is verified through extensive simulations on the six-degree-of-freedom reentry flight.

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Analysis for the power loss of electro hydrostatic actuator and hydraulic actuator

Analysis for the power loss of electro hydrostatic actuator ...

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IEEE/ASME (AIM) International Conference on Advanced Intelligent Mechatronics

作者： Wunong Hu Lei Zhou Yisong Tian Zongxia Jiao Yaoxing Shang Zengning Song Liang Yan AVIC Xi'an flight automatic control research institute Xi'an China School of Automation Science and Electrical Engineering Beihang University Beijing China

ISBN: (纸本)9781467391085

This article describes the difference between traditional airborne hydraulic actuator and electro hydrostatic actuator in heat dissipation. The power loss of the two systems are analyzed based on the method of energy transfer under different working conditions. To decrease the heating loss of electro-hydrostatic actuator, this paper designs an efficient component of the motor-pump. Theoretical and experimental analysis show that electro hydrostatic actuator is more efficient, and it is available for power saving design according to the need for energy.

关键词： Brushless motors Hydraulic actuators Heating Power generation Hydraulic fluids Valves

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A Novel Fault Detection Method Based on the UKF and Its Application to a Fifth-Order Two-Phase Nonlinear Motor System

A Novel Fault Detection Method Based on the UKF and Its Appl...

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International Conference on Intelligent Human-Machine Systems and Cybernetics, IHMSC

作者： Chang Liu Honglun Wang School of Automation Science and Electrical Engineering Beihang University Beijing China Science and Technology on Aircraft Control Laboratory Beihang University Beijing China

ISBN: (纸本)9781479986477

Small faults are difficult to be detected under noisy conditions. And the small sensor faults will introduce modeling errors in the observation equations. Therefore, small faults need be detected successfully and quickly. A novel small fault detection (FD) method is proposed using the residuals generated by the unscented Kalman filter (UKF) for a fifth-order two-phase nonlinear motor. Firstly, the introduction of the UKF is given. Secondly, on the basis of the UKF, a fault detection scheme based on a local approach is proposed. The local approach is used to detect small faults from residuals obtained from the UKF. Besides, the comparison between local approach and generalized likelihood test approach is introduced to illustrate the effectiveness of the proposed method. Finally, the proposed fault detection method is applied to detect faults of a fifth-order two-phase nonlinear motor system.

关键词： Fault detection Mathematical model Covariance matrices Jacobian matrices Noise measurement Accuracy Kalman filters

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Queue Length Optimization of Vehicles at Road Intersection Using Parabolic Interpolation Method

Queue Length Optimization of Vehicles at Road Intersection U...

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International Conference on automation, Cognitive Science, Optics, Micro Electro-Mechanical System, and Information Technology

作者： Mutiara Maulida Endra Joelianto Agus Samsi Herman Y. Sutarto Magister Program of Engineering Physics Bandung Institute of Technology Instrumentation and Control Research Group Bandung Institute of Technology Department of Electrical Engineering Harapan Bangsa Institute of Technology

ISBN: (纸本)9781467374095

Traffic congestion has become a serious problem in Indonesia, especially in Jakarta city. The main problem occurs at intersections. One of the solutions that can be proposed to reduce congestion at the intersection is to implement traffic signal control strategy at the intersection. Levels of congestion are determined by the queue length of vehicles. Green time (Tg) and red time (Tr) are determined by the queue length on each of the intersection leg. The lowest congestion level is represented by the smallest value of queue length. Optimization is performed in order to find an optimal value of green time (Tg), such that the queue length of vehicles becomes the smallest in constant cycle time. Due to the cycle time (Tn) is constant and the intersection is controlled in 2 phases, the variable needed to be optimized is only the green time (Tg). The red time (Tr) can then be counted from the cycle time (Tn) minus the green time (Tg).

关键词： Traffic Traffic congestion Traffic signal control Optimization Road Intersection traffic congestion road junctions green time Traffic vehicle Area traffic signal control Progressive traffic signal control Automatic traffic signal control Queue queueing length time cycles Intersection

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