• 제목/요약/키워드: High Accuracy

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2차원과 3차원에서의 비정렬 동적 적응격자 형성법에 관한 연구 (A Dynamic Adaptation Technique on 2-D and 3-D Unstructured Meshes)

  • 박영민;오우섭;권오준
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2000년도 춘계 학술대회논문집
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    • pp.146-152
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    • 2000
  • Two and Three dimensional dynamic adaptation code is developed for transient computations. This code involves mesh refinement and coarsening to either add points in high gradient regions of flow or remove points where they are not needed, for high spatial accuracy. Temporary cell algorithm is used to maintain the original grid quality. To show the assessment of the accuracy and efficiency, two dimensional study and unsteady flows are computed. Also, three dimensional steady computations are made to assess the refinement using temporary cell algorithm. The result shows the high spatial accuracy primarily in discontinuity regions in steady and unsteady computation.

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Linear모터의 위치 제어 성능 시험을 위한 Dynamometer 개발 (Development of a Linear Motor Dynamometer for Positioning Control Performance Test)

  • 노창렬;노명환;김주경;박종진;이응석
    • 대한기계학회논문집A
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    • 제30권5호
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    • pp.609-614
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    • 2006
  • Recently linear motor has been used mainly for high speed feeding performance of machine tools. The advantages of linear motor are not only high speed but high accuracy, because it is not required the coupling and ballscrew for converting rotary to liner motion. Before applying in different moving system, the dynamometer is necessary to test the performance. In Korea, the linear motor is producing in a couple of company However, the liner motor dynamometer is not commercialized yet, like as rotary motor dynamometer. In this paper, a linear motor dynamometer is designed and manufactured using a MR damper. The dynamometer system developed in this study could be used for testing the positioning accuracy fur different loading conditions, traction forces, dynamic performance and so on.

하드터닝에서 CBN 공구홀더의 열변형이 가공정밀도에 미치는 영향 (Analysis of Thermal Displacement of PCBN Tool Holder for Machining Accuracy in Hard Turning)

  • 노승국;이찬홍;하재용
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2003년도 춘계학술대회 논문집
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    • pp.363-366
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    • 2003
  • The hard turning is a turning operation performed in high strength alloy steels (HRC>30) in order to reach surface roughness close to those obtained in grinding. This is possible because of availability of improved tool materials (polycrystalline cubic boron nitride. PCBN), ad more rigid machine tools. According to many previous work of hard turning mechanism, the maximum temperature of cutting can be raised up to 100$0^{\circ}C$. As the heat generation rate is very high, the thermal displacement of tool holder cannot be negligible. Therefore, the aim of this paper is to analyze effects of high heat generation at CBN tool tip to the thermal displacement of a tool holder in hard turning and finally geometric accuracy. The thermal behavior of a CBN tool holder is investigated by numerical simulation and experiment, and the result shows thermal elongation of microns order is possible during hard turning process.

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초정밀서보기구의 제어성능 평가(II) (Control performance evaluation of ultra precision servo apparatus(II))

  • 김재열;김영석;곽이구;마상동;한재호
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2000년도 춘계학술대회 논문집
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    • pp.617-620
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    • 2000
  • Recently, High accuracy and precision are required in various industrial field especially, semiconductor manufacturing apparatus, Ultra precision positioning apparatus, Information field and so on. Positioning technology is a very important one among them. Is such technology has been rapidly developed, this field needs the positioning accuracy as high as submicron. It is expected that the accuracy of 10nm and 1nm is required in precision work and ultra precision work field, respectively by the beginning of 2000s. High speed and low vibration are also needed. This work deals with the design method and control system of Ultra precision positioning apparatus. We will examine the control performance and stability before manufacturing the real apparatus by using MATLAB SIMULINK based or pre-designed controller and system modeling.

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Structural Analysis and Design of Robust Motion Controllers for High-Accuracy Positioning Systems

  • Kim, Bong-Keun;Chung, Wan-Kyun
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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    • pp.467-467
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    • 2000
  • In this paper, a structural design method of robust motion controllers for high-accuracy positioning systems, which makes it possible to predict the performance of the whole closed-loop system, is proposed. First, a stabilizing control input is designed based on robust internal-loop compensate.(RTC) for the system in the presence of uncertainty and disturbance. Next, using the structural characteristics of the RIC, disturbance attenuation properties and the performance of the closed-loop system determined by the variation of controller gains are analyzed. Through this analysis, in some specific applications, it is shown that if the control gain of RIC is increased by N times, the magnitude of error is reduced to its 1/N. Finally, the proposed method is verified through experiments using a high-accuracy positioning system used in the semiconductor chip mounting devices.

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고정밀 24비트 디지털 데이터로거를 이용한 철도구조물의 경사계측에 관한 연구 (A Study of Incline Measurement using High Accuracy Digital Datalogger System for Railway Structures)

  • 이승원;이근호;정재민
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2008년도 춘계학술대회 논문집
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    • pp.249-254
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    • 2008
  • The objective of this study is the developement of real time automatic incline measurement using high accuracy digital datalogger for safety and maintence of railway construction sites. For the replacement of current 16 bit analog/digital converter, Digital datalogger system using 24 bit analog/digital converter is studied for the first time with in a country. Therefore data communication method and analyzing program of automatic measurement data is developed for the automatic high accuracy digital datalogge system. The results of this study will be using real time automatic incline measurement of railway structures.

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포항가속기연구소 디지탈 전자석 전원장치의 LC 출력필터 (LC output filter for high accuracy and stability digital controlled MPS at PLS)

  • 김성철;하기만;황정연;최진혁
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2005년도 전력전자학술대회 논문집
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    • pp.106-108
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    • 2005
  • High accuracy and stability digital controlled power supply for magnet is developed at PLS. This power supply has three sections. The first section is digital controller including DSP&FPGA and precision ADC, the second section consists of IGBT driver and four quad IGBT switch, and the third section is LC output filter section. AC input voltage of power supply is 3-phase 21V, output current is 0 ${\sim}$ 150 A dc. Switching frequency of four quad IGBT switch is 25 kHz. The output current of power supply has very high accuracy of 100 A step resolution at full range and the stability of +/- 1.5 ppm for short term and +/- 5 ppm for long term. This paper describes characteristics of filter and output current performance improvement after LC output filter at four quad digital power supplies.

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DC Servo Motor를 이용한 초정밀 위치결정기구의 컴퓨터 시뮬레이션 및 제어성능 평가 (Computer Simulation and Control performance evaluation of Ultra Precision Positioning Apparatus using DC Servo Motor)

  • 박기형;김재열;윤성운;이규태;곽이구;송인석;한재호
    • 한국생산제조학회지
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    • 제9권6호
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    • pp.164-169
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    • 2000
  • Recently, High accuracy and precision are required in various industrial field especially, semiconductor manufacturing apparatus, Ultra precision positioning apparatus, Information field and so on. Positioning technology is a very important one among them. As such technology has been rapidly developed, this field needs the positioning accuracy as high as submicron. It is expected that the accuracy of 10nm and 1nm is required in precision work and ultra precision work field, respectively by the beginning of 2000s. High speed and low vibration are also needed. This work deals with the design method and control system of Ultra precision positioning apparatus. Control performance and stability analysis were performed in advance by modeling and designing the controller with Simulink.

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철도구조물 진동계측에의 고정밀 디지털 데이터로거 적용성 연구 (A Study of Dynamic Measurement using High Accuracy Digital Datalogger System for Railway Structures)

  • 이승원;이근호;정재민
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2008년도 추계학술대회 논문집
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    • pp.1006-1011
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    • 2008
  • The objective of this study is the developement of real time automatic dynamic measurement using high accuracy digital datalogger for safety and maintence of railway construction sites. For the replacement of current 16 bit analog/digital converter, Digital datalogger system using 24 bit analog/digital converter is studied for the first time with in a country. Therefore data communication method and analyzing program of automatic measurement data is developed for the automatic high accuracy digital datalogger system. The results of this study will be using real time automatic dynamic measurement of railway structures.

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고정밀 이송을 위한 볼스크류용 체결기구에 관한 연구 (Study on the floating coupling for high precision feeding with ballscrew)

  • 박천홍;김인찬;정윤교;이후상
    • 한국정밀공학회지
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    • 제14권5호
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    • pp.157-163
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    • 1997
  • In the case of direct connecting the nut of ballscrew to guide table, machining error and misalignment of ballscrew largely affect to the motional accuracy of guideway. For decreasing these influences, two type of floating couplings: leaf spring type and hybrid type which releases the table from nut of ballscrew except feed and rotational direction is proposed in this study. In order to verify practical availability of the proposed floating couplings, motional accuracy, dynamic characteristics and micro step response of hydrostatic guideway, mounted with each type of couplings are tested. The conventional fixed type coupling is also tested as the reference in characteristics. From the results of experiments, it is proved that the hybrid type coupling is superior to other couplings and is available to high precision feeding system with ballscrew.

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