• Title/Summary/Keyword: Analytical precision

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Modeling and Uncertainty Analysis of Ballscrew Nut Stiffness (볼스크류 너트부의 강성 모델링과 불확도 해석)

  • Min, Bog-Ki;Cao, Lei;Khim, Gyungho;Park, Chun-Hong;Chung, Sung-Chong
    • Journal of the Korean Society for Precision Engineering
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    • v.32 no.5
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    • pp.415-422
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    • 2015
  • Ballscrews are important motion transfer and positioning units of industrial machinery and precision machines. Positioning accuracy of the feed drive system depends upon axial stiffness of ballscrew systems. As the nut stiffness depends upon preload and operating conditions, analytical modeling of the stiffness is performed through the contact and body deformation analysis. For accurate contact analysis, the contact angle variation between balls and grooves is incorporated in the developed model. To verify the developed mathematical stiffness model, experiments are conducted on the test-rig. Through the uncertainty analysis according to GUM (Guide to the expression of Uncertainty in Measurement), it is confirmed that the formulated stiffness model has over 85% estimation accuracy. After constructing the ballscrew DB, a quick turnaround system for the nut stiffness estimation has been developed in this research.

The Measurement Method of Small Deformation by using Holographic Interferometry (홀로그래픽 산섭법을 이용한 미소변형 측정법)

  • 강영준;문상준;최장섭
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.10a
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    • pp.273-278
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    • 1993
  • Conventional measurement methods for non-destructive testing(NDT) in nuclear power plants other industrial plants have been performed as the methods of contact with objects to be inspect, but those methods have been taken relatively much time to be inspected. Holographic interferometry which is a non-contact optical measurement method using a coherent light can overcome these demerit, and also has an advantage that the quantitative measurement of small deformation for large areas can be accomplished at a time with high precision. In this paper the comparisons of the experimental results from holographic interferometry with those form the finite element method(FEM) and the analytical solutions of elastic equation are discussed.

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A Study of Dynamic Characteristics for Frame Base of the Chip Mounter (표면실장기 기저부의 동특성 연구)

  • 성기창;박진무
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.807-811
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    • 2002
  • As the requirements on precision and speed of motion in chip mounter increase, vibration forces are always exerted on operating conditions. To insure safety of the chip mounter, the vibration must be kept within an acceptable limit. The focus of this paper is on the identification of dynamic load characteristics and the estimation of static and dynamic stiffness characteristics for Frame Base by judicious selection of the number and the location of the support points. This study carried an analytical and experimental method to estimate the dynamic characteristics in structure.

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The Spinnability of Multi-step Cylindrical Cup in Spinning Process (스피닝 공정을 이용한 다단 원형 컵 형상의 성형성에 관한 연구)

  • 박중언;한창수;최석우;김승수;나경환
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.1016-1020
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    • 2001
  • The spinning is a very effective manufacturing technology for short production runs in a variety of sizes and shapes, because it can form the cross-section or tubular parts various shapes. However extensive experimental and analytical research has not been carried out. In this study, and fundamental experiment was conducted to improve productivity with process parameter such as tool path, angle of roller holder(a), feed rate(v) and corner radius of forming roller(Rr). These factors were selected as variables in the experiment because they were most likely expected to have and effect on spring back. The clearance was controlled in order to achieve the precision product which is comparable to deep drawing one. And also thickness and diameter distribution of a multistage cup obtained by shear spinning process were observed and compared with those of a commercial product produced by conventional deep drawing.

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Ruled Surface의 곡률이론을 이용한 새로운 로봇궤적제어기법

  • 김재희;김상철;유범상
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.683-691
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    • 1997
  • This paper presents a new robot trajectory generation method based on the curvatre theory of ruled surfacees. robot trajectory is represented as a ruled surface generated by the TCP (Tool center point ) and any one unit vector among the tool frame (usually denoted O, A,N). The curvature theory of ruled surfaces provides the robot control algorithm with the motion property oarameters. The proposed method eliminates the necessity of approximation technic of either joint or cartesian interpolation. This technic may give new methodology of precision robot control. Especially this is very efficient when the robot traces an analytical or form surface if the surface is geometrically modelled.

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Analysis of flexure stiffness and stiffness test in DTG (동조 자이로스코프 서스펜션의 굽힘자 해석 및 시험)

  • Youn, J.O.;Kim, J.H.;Lee, J.G.
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.5
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    • pp.30-37
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    • 1996
  • The objective of this research is to explore the analysis and test method for the reliable design and fabrication of a high precision dynamically tuned gyroscope. The tuning frequency is decided by the calculation of mass moment of inertia of rotor and gimbal and the stiffness of flexures. Due to the complex geometry of the flexure, calculation of the stiffness of the suspension flexure is difficult. In this paper, three analytical methods for obtaining the stiffness of the flexure are porposed and a special testing method is used for checking the accuracy of the computed results.

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Time Delay Controller Design for the High Speed Precision Servo-Control of the Direct Drive Multi-axis Manipulator (고속정밀 서보제어를 위한 직구동 다관절 메니플레이터의 시간제어기 설계)

  • 이태경;김학성;정상철;최용제;안태영
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.1004-1011
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    • 1996
  • This paper covers the technology developmental stage work for the automatic ammunition loading system mainly focusing on the controller design of the electro-hydranlic type direct drive multi-axis manipulator. Mathematical model of the plant derived and PIDM servo-controller structured. Comparative study between the analytical and experimental work has been carried out to help understand the response property of the direct dine multi-axis robot. In the direct drive robot, non-negligible amount of disturbance and load Induced dynamics variation are transmitted to the drive axis and nonlinearity is highly observed. Thereupon a robust controller Implementing time-delay control law is proposed, and computer simulation confirms the possibility for the time-delay control application against the unpredictable disturbance and load-Induced dynamics variation.

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An Analytical Investigation on the Ratio of Angular Velocity in Spherical Involute Bevel Gearsets (구형 인볼류트 베벨기어쌍의 각속도비에 관한 해석적 연구)

  • Park, N.G.
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.5
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    • pp.40-45
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    • 1995
  • The kinematical relationship of bevel gearsets lies at the root of the gear design. As the demand on precision bevel gears is increased in the related industries, the kinematic analysis of a pair of sperical involute bevel gears needs to be exactly evaluated for the computer aided design. Pitch cone angles of bevel gearsets have been calculated under the assumption that the geared system is equivalent to a coned roller system without slipping. But this kinematical model involves some errors in the value of the ratio of angular velocity. In this paper, the ratio of the angular velocity is exactly derived, based on the perfect involute tooth surface. Four nonlinear equations representing the kinematical relationships are numerically solved to obtain the pitch and base cone angles. The ratios of angular volocities according to pressure and shaft angles are calculated and compared with those of the approximate gear model.

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The Measurment Method of Small Deformation by using Holographic Interferometry (홀로그래픽 간섭법을 이용한 미소변형 측정법)

  • Kang, Young-June;Moon, Sang-Joon
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.9
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    • pp.52-58
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    • 1995
  • Conventional measurement methods for non-destructive testing(NDT) in nuclear power plants and other industrial plants have been performed as the methods of contact with objects to be inspect, but those methods have been taken relatively much time to be inspected. Holographic interferometry which is a non-contact optical measurement method using a coherent light can overcome these demerit, and also has an advantage that the quantitative measurement of small deformation for large areas can be accomplished at a time with high precision. In this paper the comparisons of the experimental results form holographic interferometry with those from the finite element method(FEM) and the analytical solutions of the elastic equation are discussed.

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Quality Control on Neutron Activation Analysis for Urban Dust by the Proficiency Test (비교숙련도 시험을 통한 도시대기분진에 대한 중성자방사화분석법의 품질관리)

  • Moon, Jong-Hwa;Kim, Sun-Ha;Chung, Yong-Sam
    • Analytical Science and Technology
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    • v.15 no.5
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    • pp.433-438
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    • 2002
  • Trace elements in two air filters (V-50, P-50) artificially loaded with urban dust provided from IAEA were determined non-destructively using instrumental neutron activation analysis. Standard reference material (Urban Particulate Matter, SRM 1648) of National Institute of Standard and Technology was used for analytical quality control. About 20 elements in both of loaded filter samples were determined. To evaluate inter-laboratory comparison and proficiency test, analytical data were statistically treated with the results which collected from 49 laboratories, 40 countries participated in this study using neutron activation analysis, particle induced X-ray emission, inductively coupled plasma mass spectroscopy, etc,. From the results of statistical treatment, Z-scores are within ${\pm}2$. Furthermore, accuracy and precision of obtained analytical values are passed according to the criteria of the proficiency test. Consequently, it was proved that analytical quality for air dust samples being performed has been controlled properly.