• Title/Summary/Keyword: Initial estimate

검색결과 932건 처리시간 0.575초

Study of Developing Control Algorithm for Pumped-storage Synchronous Motor Drive

  • Park Shin-Hyun;Park Yo-Jip;Kim Jang-Mok;Baek Kwang-Ryul;Lim Ik-Hun;Ryu Ho-Seon
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • 제5B권1호
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    • pp.84-89
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    • 2005
  • This paper presents a control algorithm for a large salient-pole synchronous motor fed by a Load Commutated Inverter (LCI). Many papers have been presented in the past few years on the justification, design, and application of variable-speed drive. The focus of this paper is on high torque operation and the estimation of initial rotor position. The results of simulation indicate that it is possible to produce the maximum torque and estimate the initial rotor position.

Study of Forming Analyzing Auto-body panel by Using One-step Finite Element Method (One-Step 유한요소법을 이용한 차체판넬 성형해석에 관한 연구)

  • Jung, D.W.;Lee, C.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 한국소성가공학회 2006년도 춘계학술대회 논문집
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    • pp.261-264
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    • 2006
  • Many process parameters have an effect on the auto-body panel forming process. A well-designed blank shape causes the material to flow smoothly, reduces the punch and yields a product with uniform thickness distribution. Therefore, the determination of an initial blank shape plays the important role of saving time and cost in the auto-body panel forming process. For these reasons, some approaches to estimate the initial blank shape have been implemented in this paper, the one-step approach by using a finite element inverse method will be introduced to predict the initial blank shape the developed program is applied to auto-body panel forming.

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Design of In-Motion Alignment System of SDINS using Robust EKF

  • Hong, Hyun-Su;Lee, Jang-Gyu;Park, Chan-Gook
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.177.3-177
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    • 2001
  • In this paper, the design of the in-motion alignment system of Strapdown Inertial Navigation System(SDINS) using Robust Extended Kalman Filter(REKF) is presented. The compensation of errors in the aided navigation system is accomplished by the indirect feedback filtering. The performance of the aided navigation algorithm is very sensitive to the accuracy of the initial estimate, which is the characteristic of the EKF. Unfortunately, the initial attitude error can be very large during the in-motion alignment. To overcome the in-motion alignment under large initial attitude error problem, the REKF using linear robust filtering technique is proposed. The linear robust H$_2$ filter can be adopted for nonlinear ...

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In-Flight Alignment of SDINS without Initial Heading Information (초기 기수각 정보가 필요 없는 SDINS의 운항중 정렬)

  • 홍현수;이장규;박찬국
    • Journal of Institute of Control, Robotics and Systems
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    • 제8권6호
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    • pp.524-532
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    • 2002
  • This paper presents a new in-flight alignment method for an SDINS under large initial heading error. To handle large heading error, a new attitude error model is introduced. The attitude errors are divided into heading error and leveling errors using a newly defined horizontal frame. Some navigation error dynamic models are derived from the attitude error model for indirect feedback filtering of the in-flight alignment system. A Kalman filter with Position measurement is designed to estimate navigation errors as the indirect feedback filter Simulation results show that the proposed in-flight alignment method reduces the heading error very quickly from more than 40deg to about 5deg so as to apply a refined navigation filter. The total alignment process including leveling mode and navigation mode in addition to the proposed one allows large initial values not only in heading error but also in leveling errors.

AN INITIAL VALUE METHOD FOR SINGULARLY PERTURBED SYSTEM OF REACTION-DIFFUSION TYPE DELAY DIFFERENTIAL EQUATIONS

  • Subburayan, V.;Ramanujam, N.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제17권4호
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    • pp.221-237
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    • 2013
  • In this paper an asymptotic numerical method named as Initial Value Method (IVM) is suggested to solve the singularly perturbed weakly coupled system of reaction-diffusion type second order ordinary differential equations with negative shift (delay) terms. In this method, the original problem of solving the second order system of equations is reduced to solving eight first order singularly perturbed differential equations without delay and one system of difference equations. These singularly perturbed problems are solved by the second order hybrid finite difference scheme. An error estimate for this method is derived by using supremum norm and it is of almost second order. Numerical results are provided to illustrate the theoretical results.

A Study of One-Step Finite element method (One-Step 유한요소법에 관한 연구)

  • Ahn H. G.;Lee C. H.;Moon W. S.;Go C. S.;Jung D. W.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 한국소성가공학회 2005년도 추계학술대회 논문집
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    • pp.414-417
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    • 2005
  • Many process parameters have an effect on the auto-body panel forming process. A well-designed blank shape causes the material to flow smoothly, reduces the punch and yields a product with uniform thickness distribution. Therefore, the determination of an initial blank shape plays the important role of saving time and cost in the auto-body panel forming process. For these reasons, some approaches to estimate the initial blank shape have been implemented in this paper, the one-step approach by using a finite element inverse method will be introduced to predict the initial blank shape the developed program is applied to auto-body panel forming.

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A new method for estimating the initial position of a PM synchronous motor with an incremental encoder (영구자석 동기전동기의 초기위치를 추정하는 새로운 방법)

  • 정두희;정동욱;하인중
    • Journal of the Korean Institute of Telematics and Electronics B
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    • 제33B권7호
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    • pp.183-188
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    • 1996
  • In this paper, we propose a new method which estimates the initial position of a PM synchronous motor (PMSM) using an incremental ecoder. in cremental encoders are widely used in detecting rotor position since they are inexpensive. At starting procedure, however, the incremental encoders cannot give the information of the absolute rotor position. Hence, additional absolue encoder, which has $60^{\circ}C$ resolutio electrically, and signal lines called U, V, W, have been used in practical systems for starting injection of a high frequency test current. It does not require any additional information such as U, V, W signals for starting procedure and allows for cheap and simple implementation. Experimental results show that the proposed method can estimate the initial rotor positon with higher accuracy than the conventional method using U, V, W signals.

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An Estimate for Convergence and Efficiency of Nonlinear Shape Analysis According to the Control Techniques (제어기법에 따른 비선형 형상해석의 수렴성 및 효율성 펑가)

  • Jeong, Eul-Seok;Jeon, Jin-Hyung;Shon, Su-Deog;Kim, Seung-Deog
    • Proceeding of KASS Symposium
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    • 한국공간구조학회 2006년도 춘계 학술발표회 논문집 제3권1호(통권3호)
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    • pp.214-223
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    • 2006
  • Membrane structures, a kind of lightweight soft structural system, are used for spatial structures. The material property of the membrane has strong axial stiffness, but little bending stiffness. The design procedure of membrane structures are needed to do shape finding, stress-deformation analysis and cutting pattern generation. In shape finding, membrane structures are unstable structures initially. These soft structures need to be introduced initial stresses because of its initial unstable state, and happen large deformation phenomenon. Therefore, in this study, to find the structural shape after large deformation caused by initial stress, we need the shape analysis considering geometric nonlinear term. And we investigate the evaluation of shape analysis technique's convergence and efficiency according to the control method

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Nonlinear Analysis of 345kV Transmission Tower Considering Initial Imperfection and Residual Stress (초기결함과 잔류응력을 고려한 345kV 송전철탑의 비선형해석)

  • Chang, Jin-Won;Kim, Seung-Jun;Park, Jong-Sup;Kang, Young-Jong
    • 한국방재학회:학술대회논문집
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    • 한국방재학회 2008년도 정기총회 및 학술발표대회
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    • pp.283-286
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    • 2008
  • There were two transmission tower collapses due to Typhoon 'Maemi' in 2003. The reason that a collapse was happened was excessive wind load. One was buckled in the leg part and the other was buckled in the middle bracing part. To investigate a steel transmission tower failure mechanism, 2nd order nonlinear analysis should be performed. Considering the effect of initial imperfection and theresidual stress of angle section during nonlinear analysis, this study can estimate the ultimate strength and the ultimate behavior of the transmission tower.

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The Estimation of Link Travel Speed Using Hybrid Neuro-Fuzzy Networks (Hybrid Neuro-Fuzzy Network를 이용한 실시간 주행속도 추정)

  • Hwang, In-Shik;Lee, Hong-Chul
    • Journal of Korean Institute of Industrial Engineers
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    • 제26권4호
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    • pp.306-314
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    • 2000
  • In this paper we present a new approach to estimate link travel speed based on the hybrid neuro-fuzzy network. It combines the fuzzy ART algorithm for structure learning and the backpropagation algorithm for parameter adaptation. At first, the fuzzy ART algorithm partitions the input/output space using the training data set in order to construct initial neuro-fuzzy inference network. After the initial network topology is completed, a backpropagation learning scheme is applied to optimize parameters of fuzzy membership functions. An initial neuro-fuzzy network can be applicable to any other link where the probe car data are available. This can be realized by the network adaptation and add/modify module. In the network adaptation module, a CBR(Case-Based Reasoning) approach is used. Various experiments show that proposed methodology has better performance for estimating link travel speed comparing to the existing method.

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