• Title/Summary/Keyword: dynamic variable

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Development of An Optimal Design Program for Open-Chain Dynamic Systems (불구속연쇄 동적시스템을 위한 최적설계 프로그램 개발)

  • 최동훈;한창수;이동수;서문석
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.1
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    • pp.12-23
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    • 1994
  • This paper proposes an optimal design software for the open-chain dynamic systems whose governing equations are expressed as differential equation. In this software, an input module and an automatic creation module of the equation of motion are developed to contrive the user's convenience. To analyze the equation of motion of the dynamic systems, variable-order and variable-stepsize Adams-Bashforth-Moulton predictor-corrector method is used to improve the efficiency. For the optimization and the design sensitivity analysis, ALM(augmented lagrange multiplier)method and adjoint variable method are adopted respectively. An output module with which the user can compare and investigate the analysis and the optimization results through tables and graphs is also provided. The developed software is applied to three typical dynamic response optimization problems, and the results compare very well with those available in the literature, demonstrating its effectiveness.

A Dynamic Output Feedback Variable Structure Controller for Uncertain Systems with Unmatched System Matrix Uncertainty (부정합 시스템 행렬 불확실성을 갖는 시스템을 위한 동적 출력 궤환 가변 구조 제어기)

  • Lee, Jung-Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.11
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    • pp.2066-2072
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    • 2010
  • In this paper, a variable structure dynamic output feedback controller with an transformed sliding surface is designed for the improved robust control of a uncertain system under unmatched system uncertainty, matched input matrix uncertainty, and disturbance satisfying some conditions. This paper is extended from the results of the static output feedback VSS in [9]. To effectively remove the reaching phase problems, an initial condition of the dynamic output is determined. The previous some limitations on the dynamic output feedback variable structure controller is overcome in this systematic design. A stabilizing control is designed to generate the sliding mode on the predetermined sliding surface S=0 and as a results the closed loop exponential stability is obtained and proved together with the existence condition of the sliding mode on S=0 for all unmatched system matrix uncertainties. To show the usefulness of the algorithm, a design example and computer simulations are presented.

The Study of Dynamic Characteristic of PMLSM According to Variable Load (영구자석형 선형 동기 전동기의 가변부하에 따른 동특성 해석)

  • Lee, Seung-Hoon;Jang, Ki-Bong;Kim, Gyu-Tak
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.4
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    • pp.596-602
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    • 2008
  • This paper presents the dynamic characteristic analysis of Permanent Magnet Linear Synchronous Motor(PMLSM) according to variable load. In order to analyze dynamic characteristics, finite element method(FEM) was used for calculation of the parameter and the Matlab simulink was used for dynamic characteristic simulation. The measuring system of the dynamic characteristics was manufactured and the experiment results were compared with the simulation results.

Analysis of Dynamic Instability in a Variable-reluctance Stepping Motor Operated on Frequency-modulated Supply (주파수변조 구동에 의한 가변릴럭턴스 스텝핑모우터의 불안정 해석)

  • Kwon, Yong-Soo
    • Proceedings of the KIEE Conference
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    • 1994.07a
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    • pp.114-118
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    • 1994
  • A comprehensive analytical study of frequency-modulated supply of the dynamic instability in a variable-reluctance stepping motor, is described. It is shown that stability can be achieved by frequency modulation provided that the phase displacement between the modulating signal and the rotor velocity oscillation lies between certain limits. A simplified expression is derived. based on the assumption of high inertia. This model is used to obtain a qualitative understanding of how frequency modulation influences the dynamic stability of the variable-reluctance motor.

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The Optimum Modification of Dynamic Characteristics of Stiffened Plate Structure Including the Number of Stiffener (보강재의 수를 포함한 보강판 구조물의 동특성의 최적변경)

  • 박성현;고재용
    • Journal of the Korean Institute of Navigation
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    • v.25 no.4
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    • pp.461-469
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    • 2001
  • The purpose of this paper is the optimum modification of dynamic characteristics of stiffened plate structure including the number of stiffener. This paper shows the optimum structural modification method by dynamic sensitivity analysis and quasi-least squares method and considers it's validity. In the method of the optimization, finite element method, sensitivity analysis and optimum structural modification method are used. The change of natural frequency and total weight are made to be an objective function. Thickness of plate, the number of stiffener and cross section moment of stiffener become a design variable. The dynamic characteristics of stiffened plate structure is analyzed using finite element method. Next, rate of change of dynamic characteristics by the change of design variable is calculated using the sensitivity analysis. Then, amount of change of design variable is calculated using optimum structural modification method. It is shown that the results are effective in the optimum modification for dynamic characteristics of the stiffened plate structure including the number of stiffener.

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Dynamic Decisions using Variable Neighborhood Search for Stochastic Resource-Constrained Project Scheduling Problem (확률적 자원제약 스케줄링 문제 해결을 위한 가변 이웃탐색 기반 동적 의사결정)

  • Yim, Dong Soon
    • Journal of Korean Institute of Industrial Engineers
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    • v.43 no.1
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    • pp.1-11
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    • 2017
  • Stochastic resource-constrained project scheduling problem is an extension of resource-constrained project scheduling problem such that activity duration has stochastic nature. In real situation where activity duration is not known until the activity is finished, open-loop based static policies such as activity-based policy and priority-based policy will not well cope with duration variability. Then, a dynamic policy based on closed-loop decision making will be regarded as an alternative toward achievement of minimal makespan. In this study, a dynamic policy designed to select activities to start at each decision time point is illustrated. The performance of static and dynamic policies based on variable neighborhood search is evaluated under the discrete-event simulation environment. Experiments with J120 sets in PSPLIB and several probability distributions of activity duration show that the dynamic policy is superior to static policies. Even when the variability is high, the dynamic policy provides stable and good solutions.

Dynamic analysis of rigid roadway pavement under moving traffic loads with variable velocity

  • Alisjahbana, S.W.;Wangsadinata, W.
    • Interaction and multiscale mechanics
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    • v.5 no.2
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    • pp.105-114
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    • 2012
  • The study of rigid roadway pavement under dynamic traffic loads with variable velocity is investigated in this paper. Rigid roadway pavement is modeled as a rectangular damped orthotropic plate supported by elastic Pasternak foundation. The boundary supports of the plate are the steel dowels and tie bars which provide elastic vertical support and rotational restraint. The natural frequencies of the system and the mode shapes are solved using two transcendental equations, obtained from the solution of two auxiliary Levy's type problems, known as the Modified Bolotin Method. The dynamic moving traffic load is expressed as a concentrated load of harmonically varying magnitude, moving straight along the plate with a variable velocity. The dynamic response of the plate is obtained on the basis of orthogonality properties of eigenfunctions. Numerical example results show that the velocity and the angular frequency of the loads affected the maximum dynamic deflection of the rigid roadway pavement. It is also shown that a critical speed of the load exists. If the moving traffic load travels at critical speed, the rectangular plate becomes infinite in amplitude.

Modeling and Dynamic Characteristics Analysis of a Continuously Variable Damper with Electro-Hydraulic Pressure Control Valve (반능동현가장치용 전자제어식 연속가변댐퍼의 모델링 및 동특성 해석)

  • Do, Hong-Mun;Hong, Gyeong-Tae;Hong, Geum-Sik
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.2
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    • pp.158-166
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    • 2002
  • A mathematical model and dynamic characteristics ova continuously variable damper for semi-active suspen- sion systems are investigated. After analyzing the geometry of a typical continuously variable damper, mathematical models fur individual components including piston, orifices, spring, and valves are first derived and then the flow equations for extension and compression strokes are investigated. To verify the developed mathematical model, the dynamic response of the model are simulated using MATLAB/SIMULINK and are compared with experimental results. The proposed model can be used not only for mechanical components design but also for control system design.

An Asymptotic Solution and the Green's Function for the Transverse Vibration of Beams with Variable Properties

  • Kim, Yong-Chul
    • Journal of Ocean Engineering and Technology
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    • v.24 no.1
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    • pp.34-38
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    • 2010
  • An analytical solution procedure for the dynamic response of beams with variable properties is developed by using an asymptotic solution and the Green's function. This asymptotic closed form solution is derived for the transverse vibration of beams under the assumption of slowly varying properties, such as mass, cross-section, tension etc., along the beam length. However, this solution is still found to be very accurate even in the case of large variation, such as step change in cross-section, mass, and tension. Therefore, this derived asymptotic closed form solution and the Green's function can be easily applied to find dynamic responses for various kind of beam vibration problems.

Stabilization of elevation for gunner primary sight using variable structure control (가변구조제어에 의한 조준경 고각 안정화)

  • 김중완;이정규;김주상;이만형
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10a
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    • pp.643-647
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    • 1990
  • Gunner primary sight(GPS) stabilization system lays line of sight(LOS) to find out a target and transmits informations to the fire control system (FCS). In a moving vehicle, accuracy of LOS and FCS depends on the design of GPS and servomechanism system. The heavy vibration of vehicle on the severe off-road environment degenerates the stabilization capability of GPS. In this study, to stabilize of elevation for GPS using the variable structure control, we derived the dynamic equation of GPS system and designed the variable structure controller. Computer simulation results fulfilled the static and dynamic stability of GPS using the variable structure control.

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