• 제목/요약/키워드: Constrained nonlinear optimization

검색결과 112건 처리시간 0.029초

Time-optimal multistage controllers from the theory of dynamical cell-to-cell mappings

  • Yoon, Joong-Sun
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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    • pp.118-123
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    • 1989
  • This work deals with fast-to-compute global control laws for time-optimal motion of strongly nonlinear dynamic systems like resolute robots. the theory of cell-to-cell mappings for dynamical systems offer the possibility of doing the vast majority of the control law computation offline in case of time optimization with constrained inputs. These cells result from a coarse discretization of likely swaths of state space into a set of nonuniform, contiguous volumes of relatively simple shapes. Once the cells have been designed, the bang-bang schedules for the inputs are determined for all likely starting cells and terminating cells. the resulting control law is an open-loop optimal control law with feedback monitoring and correction.

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혼합 유전알고리즘을 이용한 비선형 최적화문제의 효율적 해법

  • 윤영수;이상용
    • 한국산업정보학회논문지
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    • 제1권1호
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    • pp.63-85
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    • 1996
  • This paper describes the applications of genetic algorithm to nonlinear constrained optimization problems. Genetic algorithms are combinatorial in nature, and therefore are computationally suitable for treating continuous and idstrete integer design variables. For several problems , the conventional genetic algorithms are ill-defined , which comes from the application of penalty function , encoding and decoding methods, fitness scaling, and premature convergence of solution. Thus, we develope a hybrid genetic algorithm to resolve these problems and present two examples to demonstrate the effectiveness of the methodology developed in this paper.

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Nonlinear section model for analysis of RC circular tower structures weakened by openings

  • Lechman, Marek;Stachurski, Andrzej
    • Structural Engineering and Mechanics
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    • 제20권2호
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    • pp.161-172
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    • 2005
  • This paper presents the section model for analysis of RC circular tower structures based on nonlinear material laws. The governing equations for normal strains due to the bending moment and the normal force are derived in the case when openings are located symmetrically in respect to the bending direction. In this approach the additional reinforcement at openings is also taken into account. The mathematical model is expressed in the form of a set of nonlinear equations which are solved by means of the minimization of the sums of the second powers of the residuals. For minimization the BFGS quasi-Newton and/or Hooke-Jeeves local minimizers suitably modified are applied to take into account the box constraints on variables. The model is verified on the set of data encountered in engineering practice. The numerical examples illustrate the effects of the loading eccentricity and size of the opening on the strains and stresses in concrete and steel in the cross-sections under consideration. Calculated results indicate that the additional reinforcement at the openings increases the resistance capacity of the section by several percent.

Optimal vibration energy harvesting from nonprismatic piezolaminated beam

  • Biswal, Alok R;Roy, Tarapada;Behera, Rabindra K
    • Smart Structures and Systems
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    • 제19권4호
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    • pp.403-413
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    • 2017
  • The present article encompasses a nonlinear finite element (FE) and genetic algorithm (GA) based optimal vibration energy harvesting from nonprismatic piezo-laminated cantilever beams. Three cases of cross section profiles (such as linear, parabolic and cubic) are modelled to analyse the geometric nonlinear effects on the output responses such as displacement, voltage, and power. The simultaneous effects of taper ratios (such as breadth and height taper) on the output power are also studied. The FE based nonlinear dynamic equation of motion has been solved by an implicit integration method (i.e., Newmark method in conjunction with the Newton-Raphson method). Besides this, a real coded GA based constrained optimization scheme has also been proposed to determine the best set of design variables for optimal harvesting of power within the safe limits of beam stress and PZT breakdown voltage.

표류신뢰도를 고려한 경제적 회로 설계에 대한 몬테칼로법의 적용 (An Application of the Monte Carlo Method to the Economical Circuit Design in Consideration of the Drift Reliability)

  • 차균현
    • 전기의세계
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    • 제24권5호
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    • pp.72-80
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    • 1975
  • In this paper an application of the Monte Carlo method to optimum circuit design is discussed. T. Tsuda and T. Kiyono's algorithm based on the Monte Carlo method for solving multiple simul-taneous nonlinear equations is generalized to apply it to finding solutions of the constrained nonlinear optimization problem. The generalized algorithm derived here is directly applied to economical circuit design. In the cirsuit design, the object function is a cost function which is related to the cost of each circuit component. The constraint is the variance of the total system expressed by the variances of each circuit component. The design is to be determined so that the circuit has specified drift reliability with minimum cost. A practical example of economical circuit design and a general nonlinear function minimization is presented with food results.

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영구자석 계자형 동기발전기의 고조파 저감을 위한 자기회로 최적설계 (Shape Optimization for the EMF Harmonics Reduction of PM type Synchronous Generators)

  • 이재건;임양수;김영균;장규홍;홍정표;장기찬
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.57-59
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    • 2001
  • This paper presents the shape optimization to minimize the BEMF(Back Electro-Motive Force) harmonics of PM type synchronous generators. RSM(Response Surface Methodology) is used to find the optimal solution. We used the 2D-Finite Element Method to obtain the observed data of the BEMF and SQP(Sequential Quadratic Problem method) is used to solve the constrained nonlinear optimization problem.

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반응표면방법론에 의한 BLDC 전동기의 코깅토크저감을 위한 최적화 (Optimization of BLDC Motor for Reduction of Cogging Torque Using Response Surface Methodology)

  • 김영균;홍정표
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 하계학술대회 논문집 B
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    • pp.647-649
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    • 2000
  • This paper presents a optimization procedure by using Response Surface Methodology(RSM) to determine design Parameters for reducing cogging torque in BLDC motor of Electric Power Steering (EPS). RSM is achieved through using the experiment design method in combination with Finite Element Method and well adapted to make analytical model for a complex problem considering a lot of interaction of these parameters. Moreover, Sequential Quadratic Problem (SQP) method is used to solve the resulting of constrained nonlinear optimization problem.

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A New Constraint Handling Method for Economic Dispatch

  • Li, Xueping;Xiao, Canwei;Lu, Zhigang
    • Journal of Electrical Engineering and Technology
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    • 제13권3호
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    • pp.1099-1109
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    • 2018
  • For practical consideration, economic dispatch (ED) problems in power system have non-smooth cost functions with equality and inequality constraints that makes the problems complex constrained nonlinear optimization problems. This paper proposes a new constraint handling method for equality and inequality constraints which is employed to solve ED problems, where the incremental rate is employed to enhance the modification process. In order to prove the applicability of the proposed method, the study cases are tested based on the classical particle swarm optimization (PSO) and differential evolution (DE) algorithm. The proposed method is evaluated for ED problems using six different test systems: 6-, 15-, 20-, 38-, 110- and 140-generators system. Simulation results show that it can always find the satisfactory solutions while satisfying the constraints.

Shape Optimization of a Plate-Fin Type Heat Sink with Triangular-Shaped Vortex Generator

  • Park, Kyoungwoo;Park, Dong-Hoon
    • Journal of Mechanical Science and Technology
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    • 제18권9호
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    • pp.1590-1603
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    • 2004
  • In this study the optimization of plate-fin type heat sink with vortex generator for the thermal stability is performed numerically. The optimum solutions in the heat sink are obtained when the temperature rise and the pressure drop are minimized simultaneously. Thermal performance of heat sink is influenced by the heat sink shape such as the base-part fin width, lower-part fin width, and basement thickness. To acquire the optimal design variables automatically, CFD and mathematical optimization are integrated. The flow and thermal fields are predicted using the finite volume method. The optimization is carried out by means of the sequential quadratic programming (SQP) method which is widely used for the constrained nonlinear optimization problem. The results show that the optimal design variables are as follows; B$_1$=2.584 mm, B$_2$=1.741 mm, and t=7.914 mm when the temperature rise is less than 40 K. Comparing with the initial design, the temperature rise is reduced by 4.2 K, while the pressure drop is increased by 9.43 Pa. The relationship between the pressure drop and the temperature rise is also presented to select the heat sink shape for the designers.

상대위치 직접 제어를 통한 정지궤도 위성의 Collocation에 관한 연구 (Station Collocation of Geostationary Spacecraft Via Direct Control of Relative Position)

  • 이재규;노태수
    • 한국항공우주학회지
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    • 제34권5호
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    • pp.56-64
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    • 2006
  • 정지궤도 위성의 상대위치보정은 제한된 위지보정 박스내에 다수의 위성을 운용함으로서 발생하는 위성간 충돌, 전파간섭, 가림현상 등을 해결하기 위해 반드시 필요한 기술이다. 본 논문에서는 정지궤도 위성의 상대 궤도 운동 분석과 최적화 기법에 근거한 문제의 정립으로 상대위치보정을 수행하였다. 이상적인 정지궤도에 대한 상대운동을 다수의 멱함수와 주기함수로 표현하고, 상대위치보정에 필요한 조건들을 이들 함수로 표현한다. 이러한 구속 조건식과 더불어 연료 최소화 같은 가격 함수를 최소화하는 과정에서 궤도 수정에 필요한 절차를 수립하게 된다. 비선형 시뮬레이션을 통하여 본 논문에서 제시하고 있는 절차의 타당성을 검증하였고 또한 기존의 고전적인 방법과 비교하였다.