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Propagation effects of low frequency electromagnetic waves in production well

Petroleum Science 2012年第2期9卷 182-191页

作者： Song Xijin Guo Baolong Dang Ruirong Wang Xuelong Institute of Intelligent Control and Image Engineering Xidian UniversityShaanxi 710071China Key Laboratory of Photoelectric Logging and Detecting of Oil and Gas Ministry of EducationXi'an Shiyou UniversityShaanxi 710065China College of Computer Science&Technology Shaanxi University of TechnologyShaanxi 710048China

The frequency domain electromagnetic method has already been widely used for tomographic imaging or electromagnetic well logging. However, different from open hole logging, the metal casing existing in production well logging has a strong shielding effect on the electromagnetic waves, thus bringing some difficulties to the application of the frequency domain electromagnetic method in production well logging. According to the relation of the field source geometry to the ring around the mandrel, the general expressions of frequency domain electromagnetic responses in axially symmetrical layered conductive medium are deduced. The propagation effects caused by the low-frequency electromagnetic waves in cased hole are also analyzed. The distribution curves of eddy current density and magnetic flux density along the radial direction in the mandrel indicate that the eddy loss within the mandrel is proportional to the transmission signal frequency and the mandrel conductivity. The secondary field responses of different casing materials show that the transmission frequency has an important effect on the ability of electromagnetic waves penetrating the metal casing. The transmission frequency should be ultra-low in order to enable the electromagnetic signal to penetrate the casing easily. The numerical results of frequency responses for different casing physical parameters show that the casing thickness has a significant impact on the choice of the transmission frequency. It is also found that the effect of the casing radius on the transmission frequency can be neglected.

关键词： Propagation effects eddy current density magnetic flux density production well frequency response

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Tracking control of Pneumatic Muscle Using Lyapunov Based control Method

Tracking Control of Pneumatic Muscle Using Lyapunov Based Co...

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2012 International Conference on Modelling,Identification and control(建模、辨别与控制国际会议 ICMIC 2012)

作者： Youssif M. T. Elobaid Jian. Huang Yongji. Wang Jun. Wu Key Laboratory of Image Processing and Intelligent Control Department of Control Science and TechnologyHuazhongUniversity of Science and TechnologyWuhanPeople’s Republic of China

Presently pneumatic muscles (PMs) are used in various applications due to their simple construction, lightweight and high force to weight ***, pneumatic muscles are facing various problems due to their nonlinear characteristic in various mechanical *** model of PM is nonlinear and *** this paper, a Lyapunov-based control (LBC) approach is proposed for the control of *** on the nonlinear characteristic of PM, a dynamic model of the PM actuator with pulling a mass against gravity is *** objectives are both a regulation and an asymptotic tracking of a desired *** analysis based on Lyapunov method with respect to our proposed control law is *** simulation results show the validity, effectiveness and enhancing robustness of the proposed method.

关键词： pneumatic muscle lyapunov theory tracking control stabilization

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Parallel Generate Entry Landing Footprint Using Differential Evolution

Parallel Generate Entry Landing Footprint Using Differential...

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International Symposium on Computer, Consumer and control (IS3C)

作者： Songtao Chang Yongji Wang Lei Liu Department of Control Science and Engineering Key Laboratory of Ministry of Education for Image Processing and Intelligent Control Huazhong University of Science and Technology Wuhan China

Landing footprint of an entry vehicle provides critical information for mission planning. Conventional methods calculate it through solving a family of multi-constraints optimal control problems. It is difficult to solve. To generate the boundary of it, we proposed a new scheme based on differential evolution(DE). Utilizing DE's parallelism, each run generates one side instead of one point of the boundary. To get the full boundary, just need run the algorithm two times. The algorithm's merits include accurate, fast, not relying on simplification of the system, all control variables are under consideration and facilitating parallel programming.

关键词： Vehicles Vehicle dynamics Optimal control Vectors Trajectory Optimization Heuristic algorithms

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Extended state observer based non-iteration predicted entry guidance

Extended state observer based non-iteration predicted entry ...

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International Conference on Modelling, Identification and control (ICMIC)

作者： Songtao Chang Mao Su Da Zhang Yongji Wang Department of Control Science and Engineering Key Laboratory of Ministry of Education for Image Processing and Intelligent Control Huazhong University of Science and Technology Wuhan China

It is difficult to guide the entry vehicle to prescribed area due to the disperse of environment and kinematics. Through predicted residual range at the current state based on drag acceleration, we developed a predictor-corrector guidance law which doesn't need iteration to figure out the reference trajectory. Then using extended state observer based controller to track the reference trajectory. We use several missions(under various disperse conditions) to test the guidance law. Simulation results demonstrated that the guidance law is able to achieve the prescribed terminal conditions under various perturbations in the aerodynamic coefficients, the density of the atmosphere and the mass of the vehicle.

关键词： Acceleration Trajectory Vehicles Observers Vehicle dynamics Planning Earth

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Active Disturbance Rejection Guidance for Ascent Using Quadratic Transition

Active Disturbance Rejection Guidance for Ascent Using Quadr...

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International Symposium on Computer, Consumer and control (IS3C)

作者： Xuefang Lu Yongji Wang Key Laboratory of Ministry of Education for Image Processing and Intelligent Control Department of Control Science and Engineering Huazhong University of Science and Technology Wuhan China

This paper presents an active disturbance rejection guidance method using quadratic transition for the atmospheric ascent guidance problem. The quadratic transition is designed from the current flight states with a reference trajectory planned off-board. For any states error, the solution of the designed quadratic transition converges to the reference trajectory. The guidance command is obtained from the derivative of the designed quadratic transition. For the unknown modeling error, the guidance command is compensated using the estimated disturbances from the extended state observer. Computer simulation for GHV (Generic Hypersonic Air Vehicle) model, which includes initial states error and modeling error, shows great accuracy and effectiveness of this guidance method.

关键词： Trajectory Atmospheric modeling Computational modeling Aerodynamics Vehicles Observers Accuracy

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Dynamic integral sliding mode for launch vehicle attitude control system

Dynamic integral sliding mode for launch vehicle attitude co...

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Chinese control and Decision Conference, CCDC

作者： Zirui Wang Lei Liu Yongji Wang Zhishen Wang Key Lab for Image Processing & Intelligent Control Huazhong University of Science & Technology Wuhan China

As it is known that launch vehicle is facing a very harsh environment during the fight process. The challenge of various perturbations and uncertainties has lead to many traditional control methods' failure to meet the requirements of attitude control system. Due to the main advantage of sliding mode control's robustness to the system uncertainties and disturbances in the so-called sliding mode, it has been widely used in engineering. In this paper, regarding particularly on chattering problem, the authors developed a novel dynamic integral sliding mode control scheme and the comparative simulation results carried out with traditional dynamic integral sliding mode demonstrates the superiority of the newly designed control law.

关键词： Sliding mode control Rockets Attitude control Simulation Vehicle dynamics Vehicles

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An application of circumscribed circle filter in the multi-stencils fast marching method 12

An application of circumscribed circle filter in the multi-s...

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27th Annual ACM Symposium on Applied Computing, SAC 2012

作者： Liu, Hong Hung, Chih-Cheng Hu, Huaifei Yu, Mali Song, Enmin School of Computer Science Huazhong University of Science and Technology Wuhan China Key Laboratory of Education Ministry for Image Processing and Intelligent Control Wuhan Hubei 430074 China School of Computing and Software Engineering Southern Polytechnic State University Marietta GA 30060 United States

ISBN: (纸本)9781450308571

We develop an effective method for improving the segmentation result based on the Multi-Stencils Fast Marching method (MSFM). In MSFM, the gradient information of the image plays a vital role for calculating edges. It is straightforward to obtain the edge of good quality images;however, MSFM may not have robust edge maps available for images with spurious edges. Thus, a special multi-direction circumscribed circle filter is proposed to calculate the image gradient information which is then used in the MSFM. Using the new gradient information, better image contours can be obtained with MSFM. The size of the radius used in our circle filter is constant even the standard deviation of zero-mean Gaussian noise changes while the parameters of mean filter and Canny filter for gradient computation have to be correctly selected according to different noisy images. Our proposed method shows that it is effective through the experiments of image segmentation. © 2012 ACM.

关键词： image segmentation

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Textural fabric defect detection using adaptive quantized Gray-level Co-occurrence Matrix and Support Vector Description Data

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Information Technology Journal 2012年第6期11卷 673-685页

作者： Bi, Mingde Sun, Zhigang Li, Yesong Key Laboratory of Ministry of Education for Image Processing and Intelligent Control Department of Control Science and Engineering Huazhong University of Science and Technology 1037 Luoyu Road Hubei 430074 Wuhan China

A new defect detection algorithm base on Support Vector Data Description (SVDD) is proposed. A fabric texture model is built on the gray-level histogram of textural fabric image. Two Gray-level Co-occurrence Matrix (GLCM) features are used to characterize the fabric texture. And an adaptive quantization scheme base on the texture mode is proposed to reduce the size of GLCM and reduce the computational complexity of feature extraction. Besides, twonew features are proposed to characterize the continuous property of the fabric defects. The SVDD classifier is used as a detector for defect detection. Experimental results of real fabric defects are provided to validate the effectiveness and robustness of the proposed detection algorithm. And a prototyped detection system is built to evaluate the real-time performance of the detection algorithm. © 2012 Asian Network for Scientific Information.

关键词： Data description

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Adaptive flocking of multi-agent systems with locally Lipschitz nonlinearity

Adaptive flocking of multi-agent systems with locally Lipsch...

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31st Chinese control Conference, CCC 2012

作者： Ningzi, Zhang Housheng, Su Chen, Michael Z. Q. Xiaofan, Wang Department of Control Science and Engineering Image Processing and Intelligent Control Key Laboratory of Education Ministry of China Huazhong University of Science and Technology Wuhan 430074 China Department of Mechanical Engineering University of Hong Kong Hong Kong Hong Kong Department of Automation Shanghai Jiao Tong University Shanghai 200240 China

ISBN: (纸本)9789881563811

This paper investigates adaptive flocking of multi-agent systems (MASs) with a virtual leader. All agents and the virtual leader share the same intrinsic nonlinear dynamics, which satisfies a locally Lipschitz condition and depends on both position and velocity information of the agent itself. Under the assumption that the initial network is connected, an approach to preserving the connectivity of the network is proposed. Based on the Lyapunov stability theory, an adaptive flocking control law is derived to make the MASs track the virtual leader without collision. Finally, a numerical example is presented to illustrate the effectiveness of the theoretical results. © 2012 Chinese Assoc of Automati.

关键词： Multi agent systems

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Tracking control of Pneumatic Muscle Using Lyapunov Based control Method

Tracking Control of Pneumatic Muscle Using Lyapunov Based Co...

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4th International Conference on Modelling,Identification and control(ICMIC 2012)

作者： Youssif M.T.Elobaid Key Laboratory of Image Processing and Intelligent Control Department of Control Science and TechnologyHuazhong University of Science and Technology Wuhan People’s Republic of China

Presently pneumatic muscles (PMs) are used in various applications due to their simple construction, lightweight and high force to weight ratio. However, pneumatic muscles are facing various problems due to their nonlinear characteristic in various mechanical applications. The model of PM is nonlinear and time-varying. In this paper, a Lyapunov-based control (LBC) approach is proposed for the control of PM. Based on the nonlinear characteristic of PM, a dynamic model of the PM actuator with pulling a mass against gravity is formed. control objectives are both a regulation and an asymptotic tracking of a desired trajectory. Stability analysis based on Lyapunov method with respect to our proposed control law is discussed. The simulation results show the validity, effectiveness and enhancing robustness of the proposed method.

关键词： Pneumatic muscle, Lyapunov theory, tracking control, stabilization.

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