• 제목/요약/키워드: Speed profile optimization

검색결과 47건 처리시간 0.021초

곡선부에서 차륜 마모 저감을 위한 차륜답면 형상 설계 (Design of Wheel Profile to Reduce Wear of Railway Wheel)

  • 최하영;이동형;송창용;이종수
    • 한국정밀공학회지
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    • 제29권6호
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    • pp.607-612
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    • 2012
  • The wear problem of wheel flange occurs at sharp curves of rail. This paper proposes a procedure for optimum design of a wheel profile wherein flange wear is reduced by improving an interaction between wheel and rail. Application of optimization method to design problem mainly depends on characteristics of design space. This paper compared local optimization method with global optimization according to sensitivity value of objective function for design variables to find out which optimization method is appropriable to minimize wear of wheel flange. Wheel profile is created by a piecewise cubic Hermite interpolating polynomial and dynamic performances are analyzed by a railway dynamic analysis program, VAMPIRE. From the optimization results, it is verified that the global optimization method such as genetic algorithm is more suitable to wheel profile optimization than the local optimization of SQP (Sequential Quadratic Programming) in case of considering the lack of empirical knowledge for initial design value.

듀얼 레일 형상에 적합한 철도차량의 차륜 형상 설계 (Design of Railway Vehicle Wheel Profile Suitable for Dual-rail Profile)

  • 변성광;이동형;최하영
    • 한국기계가공학회지
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    • 제16권3호
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    • pp.30-37
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    • 2017
  • When a wheel profile of a train-tram is designed, both train and tram tracks should be considered. This study designed a wheel profile that enables high-speed driving(200km/h) on the train track and low speed driving on the tram track with multiple sharp curves. The study used the approximation optimization method to reduce cost and time, used the sequential quadratic programming method as the optimized algorithm, and the central composite design and response surface method as an approximate model. The optimized wheel shape based on this approximation optimization method reduced wear of the initial wheel showed a better performance in terms of derailment and lateral force.

자동차용 타이어 단면형상의 최적설계 방법론 (Optimal Design Methodology of Automotive Tire Profile)

  • 황준;남궁석
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1996년도 추계학술대회 논문집
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    • pp.896-900
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    • 1996
  • New approach to determine the optimal design of automotive tire profile was introduced. In this study, optimal design technology was combined with a finite element method. Through tire profile optimization, tire profile was obtained and its profile improved high speed durability and maneuverability Static and dynamic behavior analysis of new concepted tire was compared with conventional tire profile. Optimal design methodology will provide much informations to improve various tire performances.

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고속 LCD 이송 시스템의 진동감소를 위한 Finite Jerk 적용 가속도 최적화 (Acceleration Optimization of a High-speed LCD Transfer Crane Using Finite Jerk)

  • 송태진;홍대선;김호종;방덕제;정원지
    • 한국정밀공학회지
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    • 제23권3호
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    • pp.110-117
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    • 2006
  • This paper presents the acceleration optimization of a high-speed LCD (Liquid Crystal Display) transfer system for the minimization of vibration. To reduce vibration is one of key requirements for the dynamic control of a high-speed LCD transfer system. In this paper, the concept of finite jerk (the first derivative of acceleration) has been introduced for realizing input acceleration. The profile of finite jerk has been optimized using a genetic algorithm so that vibration effect can be minimized. In order to incorporate a genetic algorithm, the dynamic model of a LCD transfer system which is realized by using the ADAMS software has been linked to the simulation system constructed by the MATLAB. The simulation results illustrated that the duration of finite jerk can be optimized so as to minimize the magnitude of vibration. It has been also shown that the acceleration optimization with finite jerk can make the high-speed motion of a LCD transfer system result in low vibration, compared with the conventional motion control with trapezoidal velocity profile.

다수 드론의 충돌 회피를 위한 경로점 구간 속도 프로파일 최적화 (Multiple Drones Collision Avoidance in Path Segment Using Speed Profile Optimization)

  • 김태형;강태영;이진규;김종한;유창경
    • 한국항공우주학회지
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    • 제50권11호
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    • pp.763-770
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    • 2022
  • 다수의 드론이 운용되는 환경에서 경로점이 겹칠 때 충돌이 발생할 수 있으며 이를 대비한 충돌 회피는 필수적이다. 다수의 드론이 여러 임무를 수행하는 경우 드론의 경로가 복잡하고 충돌 예상점이 너무 많아 경로계획 단계에서 충돌을 회피하는 경로를 생성하는 방법을 사용하는 것은 적합하지 않다. 본 논문에서는 일반적으로 사용하는 경로 생성 알고리즘을 통해 경로를 생성하고, 그 경로에서 속도 프로파일 최적화를 이용한 충돌 회피 방법을 제안한다. 드론의 경로 간 충돌 예상점에서 드론 사이의 안전거리를 고려하였고, 경로 구간에 속도 프로파일을 할당하도록 설계하였다. 최적화 문제는 드론 간 거리에 대한 식을 비행시간을 변수로 두어 정의하였다. 선형화와 컨벡스화를 통해 구속 조건을 구성하고, 다수 드론 운용 환경에서 SQP(Sequential Quadratic Programming)알고리즘과 컨벡스 최적화 기법의 연산시간을 비교하였다. 마지막으로 20대 드론 운용 환경에서 컨벡스 최적화를 수행한 결과가 본 연구에서 제시한 다수 드론 운용에 적합한지 확인하였다.

Linear Motor 이송계의 진동 최소화를 위한 이송속도 최적화 (A Study on the Feed Rate Optimization of a Linear Motored Feed Drive System for Minimum Vibrations)

  • 최영휴;홍진현;최응영;김태형;최원선
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2004년도 추계학술대회 논문집
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    • pp.321-325
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    • 2004
  • Linear motor feed drive systems have been broadly used in machine tools or precision automatic feed systems. Recently, modem machine tools require high speed and high precision feed drive system to achieve high productivity. Unfortunately, a feed drive system, even though it was optimum designed, may experience severe transient vibrations during high-speed operation if its feed rate control is unsuitable. A rough feed rate curve having discontinuity in its acceleration profile causes a serious vibration problem in the feed slides system. This paper presents a feed rate optimization of a machine tool feed slide system, which is driven by a linear motor, for its minimum vibrations. Firstly, a 4-degree-of-freedom lumped parameter model is proposed for the vibration analysis of a linear motor driven machine tool feed drive system. Next, a feed rate optimization of the feed slide is carried out for minimum vibrations. The feed rate curve optimization strategy is to find out the most appropriate acceleration profile with jerk continuity. Of course, the optimized feed rate should approximate to the desired one as possible. A genetic algorithm with variable penalty function was used in this feed rate optimization.

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볼스크류 이송계의 진동 최소화를 위한 이송속도 최적화 (A Study on the Feed Rate Optimization of a Ball Screw Feed Drive System for Minimum Vibrations)

  • 최영휴;홍진현
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 추계학술대회논문집
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    • pp.962-966
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    • 2004
  • Ball screw feed drive systems have been broadly used in machine tools or precision automatic feed systems. Recently, modern machine tools require high speed and high precision and drive system to achieve high productivity. Unfortunately, a feed drive system, even though it was optimum designed, may experience severe transient vibrations during high-speed operation if its feed rate control is unsuitable. A rough feed rate curve having discontinuity in its acceleration profile causes a serious vibration problem in the feed slide system. This paper presents a feed rate optimization of a machine tool feed slide system, which is driven by a ball screw, for its minimum vibrations. Firstly, a 6-degree-of-freedom lumped parameter model was proposed for the vibration analysis of a ball screw driven machine tool feed drive system. Next, a feed rate optimization of the feed slide was carried out for minimum vibrations. The feed rate curve optimization strategy is to find out the most appropriate acceleration profile having finite jerk. Of course, the optimized feed rate should approximate to the desired one as possible. A genetic algorithm with variable penalty function was used in this feed rate optimization.

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등가답면구배를 목적함수로 하는 차륜답면형상 설계기법 (Design Method of Railway Wheel Profile with Objective Function of Eqivalent Conicity)

  • 허현무;유원희;박준혁;김민수
    • 한국정밀공학회지
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    • 제27권8호
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    • pp.13-19
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    • 2010
  • A design method of railway wheel profile with objective function of equivalent conicity considering wheel dimension constraint, two points contact problem between wheel and rail was proposed. New design method shows good results. New wheel profile generated from optimization process shows better dynamic performance compared with initial profile as the purpose of wheel profile design. And to verify the design method with testing the stability of new wheel profile, we conducted a critical speed test for new wheel profile using scale model applied scaling method of railway vehicle dynamics. The result of critical speed test show good agreement with that of numerical analysis. From the above results, it is seen that the design method with objective function of equivalent conicity is feasible and it could be applied to design new wheel profile efficiently.

퍼지 이론을 이용한 고속 회전용 스위치드 리럭턴스 모터의 형상 최적 설계 (Optimal Shape Deign of a High Speed Switched Reluctance Motor Vsing Fuzzy Set Theory)

  • 최창환;유재선;박기환
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제49권10호
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    • pp.659-664
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    • 2000
  • This paper presents a new design method for improving the torque performance of a switched reluctance motor (SRM) for high speed applications. The drawback of the conventional design method based on the overall static average torque maximization is that the torque control performance is degraded at high speed. On the other hand, the proposed method optimizes the torque profile by diving it into several regions so that it is suitable for high speed operation. This multi-objective optimization problem is solved by using a fuzzy optimization algorithm which incorporates a finite element method. The torque performance of the motor for various speed ranges is investigated and the optimally designed motor show a better performance at high speed.

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제한 주행시간을 만족하는 에너지 효율적인 전기자동차 주행 최적화 기법 (Energy Efficient Electric Vehicle Driving Optimization Method Satisfying Driving Time Constraint)

  • 백돈규
    • 한국산업정보학회논문지
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    • 제25권2호
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    • pp.39-47
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    • 2020
  • 본 논문은 추가 비용 없이 전기자동차(EV) 주행 범위를 확장하기 위해 에너지 효율적인 전기자동차 주행 프로파일을 도출하는 새로운 시스템 수준의 프레임 워크를 소개한다. 이 논문은 먼저 운전 차량에 작용하는 힘과 모터 효율을 고려한 전기차 파워 트레인 모델을 구현한 후, 경로에 의해 정의된 주행 임무에 대한 최소 에너지 주행 프로파일을 도출한다. 이를 위해서 본 프레임워크는 먼저 최적화 문제를 공식화하고, 가중치 계수를 이용한 동적 프로그래밍 알고리즘을 사용하여 에너지 소비와 운전 시간을 모두 최소화하는 주행 프로파일을 도출한다. 본 논문은 주행 시간 제약을 만족시키기 위한 다양한 가중치 계수 도출 방법을 소개한다. 시뮬레이션 결과, 제안 된 스케일링 알고리즘의 연산시간이 이진 검색 알고리즘 및 탐욕 알고리즘보다 각각 34 % 및 50 % 더 작음을 보여준다.