• 제목/요약/키워드: Nonlinear optimal design

검색결과 595건 처리시간 0.026초

디지틀 컴퓨터에 의한 복합영농(複合營農) 시스템의 최적화(最適化) 연구(硏究)(II) -최적설계(最適設計) (Optimizing Diversified Farming Systems by Digital Computer(II) -Optimal Design)

  • 장동일;김기철;이상우;김만수
    • Journal of Biosystems Engineering
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    • 제11권2호
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    • pp.77-87
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    • 1986
  • This study was carried out to design the optimal systems of diversified farming by the mathematical model developed. In order to achieve this goal, a computer program named DFSDINGP was developed by the nonlinear goal programming(NGP), and for testing its effectiveness, the optimal systems of diversified farming were designed for three regions surveyed and compared them with those of the conventional. DFSDINGP was programmed with FORTRAN 77 and it could handle the NGP problem having 25 independent variables and 75 constraint functions. The study results showed that the developed models and DFSDINGP could design the optimal systems of diversified farming satisfying two goals which are maximum agricultural income and maximum power inputs of agricultural machinery. The agricultural incomes and power inputs of farm machinery of the optimal systems were more than those of the conventional as much as 29-62% and 9-134%, respectively.

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경사기능재료 판의 최적설계 (Optimal Design of Functionally Graded Plates)

  • 나경수;김지환
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2006년도 춘계학술대회논문집
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    • pp.1061-1064
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    • 2006
  • Optimal design of functionally graded plates is investigated considering stress and critical temperature. Material properties are assumed to be temperature dependent and varied continuously in the thickness direction. The effective material properties are obtained by applying linear rule of mixtures. The 3-D finite element model is adopted using an 18-node solid element to analyze more accurately the variation of material properties and temperature field in the thickness direction. For stress analysis, the tensile stress ratio and compressive stress ratio of the structure under mechanical load are investigated. In the thermo-mechanical buckling analysis, temperature at each node is obtained by solving the steady-state heat transfer problem and Newton-Raphson method is used for material nonlinear analysis. Finally, the optimal design of FGM plates is studied for stress reduction and improving thermo-mechanical buckling behavior, simultaneously.

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Robust Optimization with Static Analysis Assisted Technique for Design of Electric Machine

  • Lee, Jae-Gil;Jung, Hyun-Kyo;Woo, Dong-Kyun
    • Journal of Electrical Engineering and Technology
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    • 제13권6호
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    • pp.2262-2267
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    • 2018
  • In electric machine design, there is a large computation cost for finite element analyses (FEA) when analyzing nonlinear characteristics in the machine Therefore, for the optimal design of an electric machine, designers commonly use an optimization algorithm capable of excellent convergence performance. However, robustness consideration, as this factor can guarantee machine performances capabilities within design uncertainties such as the manufacturing tolerance or external perturbations, is essential during the machine design process. Moreover, additional FEA is required to search robust optimum. To address this issue, this paper proposes a computationally efficient robust optimization algorithm. To reduce the computational burden of the FEA, the proposed algorithm employs a useful technique which termed static analysis assisted technique (SAAT). The proposed method is verified via the effective robust optimal design of electric machine to reduce cogging torque at a reasonable computational cost.

A Model Predictive Controller for Nuclear Reactor Power

  • Na Man Gyun;Shin Sun Ho;Kim Whee Cheol
    • Nuclear Engineering and Technology
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    • 제35권5호
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    • pp.399-411
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    • 2003
  • A model predictive control method is applied to design an automatic controller for thermal power control in a reactor core. The basic concept of the model predictive control is to solve an optimization problem for a finite future at current time and to implement as the current control input only the first optimal control input among the solutions of the finite time steps. At the next time step, the second optimal control input is not implemented and the procedure to solve the optimization problem is then repeated. The objectives of the proposed model predictive controller are to minimize the difference between the output and the desired output and the variation of the control rod position. The nonlinear PWR plant model (a nonlinear point kinetics equation with six delayed neutron groups and the lumped thermal-hydraulic balance equations) is used to verify the proposed controller of reactor power. And a controller design model used for designing the model predictive controller is obtained by applying a parameter estimation algorithm at an initial stage. From results of numerical simulation to check the controllability of the proposed controller at the $5\%/min$ ramp increase or decrease of a desired load and its $10\%$ step increase or decrease which are design requirements, the performances of this controller are proved to be excellent.

진동특성 및 측면충돌 성능을 고려한 차체의 점용접 치수 최적화 연구 (A Study on Optimal Spot-weld Layout Design of the Vehicle Body Structure Considering Vibration and Side Impact)

  • 신경호;이준영;박홍익;임홍재
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2012년도 추계학술대회 논문집
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    • pp.750-755
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    • 2012
  • In this study we conduct the optimal spot-weld layout design of vehicle body structure considering dynamic stiffness and side impact. We conduct both linear static analysis and nonlinear analysis with a baseline model to verify the process. 13 design variables will be selected for the effect analysis. Then, topology optimization is conducted to each selected design variable. The design constraints are formulated to improve the dynamic stiffness and side impact performance. Objective function is to set the density of weld component. Optimal spot-weld layout design are compared with the baseline model to show the improvement.

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Robust ILQ controller design of hot strip mill looper system

  • Kim, Seong-Bae;Hwang, I-Cheol
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.75.5-75
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    • 2001
  • In this paper, we study design of a ILQ(Inverse Linear Quadratic optimal control) looper control system for hot strip mills. The looper which is placed between stands plays an important role in controlling strip width by regulating strip tension variation generated from the velocity difference of main work rolls. A Looper servo controller is designed by ILQ control theory which is an inverse problem of LQ(Linear Quadratic optimal control) control. The mathematical model for looper system is obtained by Taylor´s linearization of nonlinear differential equations. Then we designed linear controller for linearization model by using the ILQ control algorithm. Thereafter this controller is applied to the nonlinear model for model identification. As a result, we show the controller´s robustness for the model error, external disturbance and sensor noise.

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구동 링크기구 최적설계 분석 및 대부하 구동제어 성능추정 프로그램 개발 (Optimal Design Analysis of Link-Mechanism and Development of Control Performance Estimation Program for Unbalanced Heavy-Loaded Drive System)

  • 최근국;이만형;안태영
    • 한국정밀공학회지
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    • 제16권6호
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    • pp.7-13
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    • 1999
  • The unbalanced heavy-loaded elevation-driving system is composed of link-mechanism, hydraulic cylinder and compensator for the static unbalanced moment of the load. Control and compensation of elevation-driving system is very difficult because these mechanisms imply highly nonlinear properties due to hydraulic fluid characteristics and mechanical rotation of link-mechanism. In this study, through the analysis of the link-mechanism, the optimal design of the link-mechanism is suggested. Also to estimate the control performance of the unbalanced, heavy-loaded servo-controlled system, modeling and simulation of nonlinear system are carried out. To prove the validity of performance estimation program, simulation results are compared with the experimental results. Both results are similar, therefore this program will be helpful to study the improvement of the system control performance.

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유전 알고리즘을 이용한 비선형 시스템의 최적 신경 회로망 구조에 관한 연구 (A Study on Optimal Neural Network Structure of Nonlinear System using Genetic Algorithm)

  • 김홍복;김정근;김민정;황승욱
    • 한국항해항만학회지
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    • 제28권3호
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    • pp.221-225
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    • 2004
  • 본 논문은 신경 회로망과 유전 알고리즘을 이용한 비선형 시스템 모델링을 다룬다. 비선형 함수의 근사성 때문에 시스템을 식별하고 제어하기 위해서 신경 회로망을 응용한 연구가 실제로 많이 이루어지고 있다. 빠른 응답시간과 최소의 오차를 위해서는 최적구조 신경 회로망을 설계하는 것이 중요하다. 유선 알고리즘은 최근에 단순성과 견고성 때문에 점점 많이 이용되는 추세이다. 따라서 본 논문에서는 유선알고리즘을 이용하여 신경회로망을 최적화한다. 오차와 응답시간을 최소화하는 신경 회로망 구조를 위해서 유전알고리즘의 유전자로 이진 코딩하여 최적 신경회로망을 탐색하고자 한다. 시뮬레이션을 통해서, 최적 신경회로망 구조가 비선형 시스템 식별에 효과적인 것을 입증하고자 한다.

단일상태 귀환 제어계의 최적 비선형제어기 설계에 관한 연구 (A Study on the Design of the Optimal Nonlinear Controller for Single State Feedback)

  • 노용균;조겸래;이진걸
    • 한국정밀공학회지
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    • 제6권1호
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    • pp.85-92
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    • 1989
  • For feedback control of a linear dynamic system the optimum linear state regulator (OLSR) can be implemented only if all states are available for feedback. This work demonstrates that when only the output state is available for feedback, a nonlinear controllers can give improved performance over that obtained by a proportional controller. This paper found the optimal control law by dynamic programming and principles of optimalityl. This, performances of both proportional and nonlinear controllers are compared with performance of optimum linear state regulator.

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Improved Two Points Algorithm For D-optimal Design

  • Ahn, Yunkee;Lee, Man-Jong
    • Communications for Statistical Applications and Methods
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    • 제6권1호
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    • pp.53-68
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    • 1999
  • To improve the slow convergence property of the steepest ascent type algorithm for continuous D-optimal design problems. we develop a new algorithm. We apply the nonlinear system of equations as the necessary condition of optimality and develop the two-point algorithm that solves the problem of clustering. Because of the nature of the steepest coordinate ascent algorithm avoiding the problem of clustering itself helps the improvement of convergence speed. The numerical examples show the performances of the new method is better than those of various steepest ascent algorithms.

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