• Title/Summary/Keyword: effective parameter

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Design of an Adaptive Variable Structure Control using Fredholm Integral Formulae for the Uncertainties (불확실성의 Fredholm 적분 수식화를 통한 적응가변구조제어기 설계)

  • 유동상
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.9
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    • pp.658-663
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    • 2003
  • In deterministic design of feedback controllers for uncertain dynamic systems, the upper bound of the uncertainty is very important to guarantee the stability of the closed loop system. In this paper, we assume that the upper bound of the uncertainty is formulated using a Fredholm integral equation of the first kind, that is, an integral of the product of a predefined kernel with an unknown influence function. We propose an adaptation law that is capable of estimating this upper bound. Using this adaptive upper bound, we design an adaptive variable structure control (AVSC), which guarantees asymptotic stability/ultimate boundedness of uncertain dynamic systems. The illustrative example shows the proposed AVSC is effective for uncertain dynamic systems.

On Designing A Fuzzy-Neural Network Control System Combined with Genetic Algorithm (유전알고리듬을 결합한 퍼지-신경망 제어 시스템 설계)

  • 김용호;김성현;전홍태;이홍기
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.32B no.8
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    • pp.1119-1126
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    • 1995
  • The construction of rule-base for a nonlinear time-varying system, becomes much more complicated because of model uncertainty and parameter variations. Furthemore, FLC does not have an ability of adjusting rule- base in responding to some sudden changes of control environments. To cope with these problems, an auto-tuning method of the fuzzy rule-base is required. In this paper, the GA-based Fuzzy-Neural control system combining Fuzzy-Neural control theory with the genetic algorithm(GA), which is known to be very effective in the optimization problem, will be proposed. The tuning of the proposed system is performed by two tuning processes(the course tuning process and the fine tuning/adaptive learning process). The effectiveness of the proposed control system will be demonstrated by computer simulations using a two degree of freedom robot manipulator.

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A Study of Basic Design for the Traction Motor (Traction Motor 설계에 관한 연구)

  • Kim, Won-Ho;Bae, Jae-Nam;Jang, Ik-Sang;Lee, Ju
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.1395-1401
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    • 2010
  • A paradigm shift in driving system of transportation vehicle from engine to electric motor is required as the problems on air pollution and drain of petroleum resource are on the rize. Moreover while it is possible to control the motor with variable frequency driver, the application of motor in various kinds of vehicles is spread rapidly. In the paper, the effective design method of IPMSM for EV and HEV by using equivalent magnetic circuit and finite element method (FEM) is suggested. First of all, load conditions of the application are calculated. And basic design process of IPMSM is proposed with two design point. Finally, in order to verify the proposed design process, it was compared with the basic design parameter and the FEM analysis results.

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Geostatistics for Bayesian interpretation of geophysical data

  • Oh Seokhoon;Lee Duk Kee;Yang Junmo;Youn Yong-Hoon
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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    • pp.340-343
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    • 2003
  • This study presents a practical procedure for the Bayesian inversion of geophysical data by Markov chain Monte Carlo (MCMC) sampling and geostatistics. We have applied geostatistical techniques for the acquisition of prior model information, and then the MCMC method was adopted to infer the characteristics of the marginal distributions of model parameters. For the Bayesian inversion of dipole-dipole array resistivity data, we have used the indicator kriging and simulation techniques to generate cumulative density functions from Schlumberger array resistivity data and well logging data, and obtained prior information by cokriging and simulations from covariogram models. The indicator approach makes it possible to incorporate non-parametric information into the probabilistic density function. We have also adopted the MCMC approach, based on Gibbs sampling, to examine the characteristics of a posteriori probability density function and the marginal distribution of each parameter. This approach provides an effective way to treat Bayesian inversion of geophysical data and reduce the non-uniqueness by incorporating various prior information.

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The Characteristics of Soil Remediation by Soil Flushing System Using PVDs (연직배수재를 이용한 토양세정시스템의 오염토양정화 특성)

  • Park, Jeong-Jun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.10 no.5
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    • pp.76-86
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    • 2007
  • For the purpose of ground improvement by means of soil flushing systems. Incorporated technique with prefabricated vertical drains have been used for dewatering from fine-grained soils. The laboratory model tests were performed by using the flushing tracer solutions for silty soils and recorded the tracer concentration changes with the elapsed time and flow rates. A mathematical model for prediction of contaminant transport using the PVD technology has been developed. The clean-up times for the predictions on both soil condition indicate more of a sensitivity to the dispersivity parameter than to the extracted flow rate and vertical velocity parameters. Based on the results of the analyses, numerical analysis indicate that the most important factor to the in-situ soil remediation in prefabricated vertical drain system is the effective diameter of contaminated soil.

Zeroth-Order Shear Deformation Micro-Mechanical Model for Periodic Heterogeneous Beam-like Structures

  • Lee, Chang-Yong
    • Journal of Power System Engineering
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    • v.19 no.3
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    • pp.55-62
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    • 2015
  • This paper discusses a new model for investigating the micro-mechanical behavior of beam-like structures composed of various elastic moduli and complex geometries varying through the cross-sectional directions and also periodically-repeated along the axial directions. The original three-dimensional problem is first formulated in an unified and compact intrinsic form using the concept of decomposition of the rotation tensor. Taking advantage of two smallness of the cross-sectional dimension-to-length parameter and the micro-to-macro heterogeneity and performing homogenization along dimensional reduction simultaneously, the variational asymptotic method is used to rigorously construct an effective zeroth-order beam model, which is similar a generalized Timoshenko one (the first-order shear deformation model) capable of capturing the transverse shear deformations, but still carries out the zeroth-order approximation which can maximize simplicity and promote efficiency. Two examples available in literature are used to demonstrate the consistence and efficiency of this new model, especially for the structures, in which the effects of transverse shear deformations are significant.

An Experimental Study on Automobile Tire Road Noise for Design of Automobile Chassis (자동차 섀시 설계를 위한 자동차 타이어 도로소음에 관한 실험적 연구)

  • Kim, Byoung-sam
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.4 s.97
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    • pp.375-381
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    • 2005
  • The purpose of this study is to obtain a foundation data for chassis design and road noise reduction of automobiles. Using the combination of the automobile, radial tires and instrumentation equipment, experimental investigation were carried out to examine the characteristics of the structural vibration of tire as the key to obtaining the effective parameters for reducing road noise. From the results of experimental studies it has been confirmed that the existence of important frequency ranges, which were attributable to the suspension and chassis system. The tire, axle and chassis natural frequency of automobile govern the road noise. Results that material property of tire and experimental condition are parameter for shifting of tire natural frequency, which enables a designer of an automobile to foresee the influence of the various design factors on the road noise.

A Development of the Test Apparatus for Measuring the Acoustic Stiffness of Resilient Mounts (마운트의 음향강성 측정을 위한 시험장치 개발)

  • 배수룡;정우진;함일배;김두기;이헌곤
    • Journal of KSNVE
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    • v.9 no.1
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    • pp.141-148
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    • 1999
  • Resilient mounting is effective measures to reduce the structure-borne noise and radiated noise for many applications. The acoustic stiffness (frequency-dependent stiffness) of resilient mounts is an important parameter required in order to model vibration isolation with high accuracy. It is general to use measurement method for obtaining acoustic stiffness of complex resilient mounts under static preload. In this paper, the principles of measuring acoustic stiffness were described and the developed test apparatus was introduced. Also, the feasibility of the test apparatus is illustrated by measurement results of a resilient mount.

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Mode-decoupling controller for feedback model updating (궤환 모델 개선법을 위한 모드 분리 제어기)

  • 정훈상;박영진
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.05a
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    • pp.864-869
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    • 2004
  • A novel concept of feedback loop design for modal test and model updating is proposed. This method uses the closed -loop natural frequency information for parameter modification to overcome the problems associated with the conventional method employing the modal sensitivity matrix. To obtain new modal information from closed-loop system, controllers should be effective in changing modal data while guaranteeing the stability of closed-loop system. It is very hard to guarantee the stability of the closed-loop system with non-collocated sensor and actuator set. Ill this research, we proposed a controller called mode-decoupling controller that can change a target mode as much as the designer wants guaranteeing the stability of closed-loop system. This controller can be computed just using measured open-loop modeshape matrix. A simulation based on time domain input/output data is performed to check the feasibility of proposed control method.

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Vibration Analysis of Boring Bar with Dynamic Vibration Absorber (동흡진기형 보링바의 진동해석)

  • Lee, Jae-Hyuk;Rim, Kyung-Hwa
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.1796-1802
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    • 2000
  • The purpose of this work is to analyze the vibration characteristic of boring bar with dynamic vibration absorber and find out the effective design parameters. Using the finite element method and modified optimum design concept, conventional optimum design based on approximate lumped parameter model is checked and practical design to be measured with modal analysis is compared with optimum design from numerical analysis. Also, the performance of reducing vibration is investigated with variation of shape of boring bar. The considered model of boring bar with dynamic vibration absorber is selected among manufactured boring bars with the best performance.

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