• Title/Summary/Keyword: ball

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A Visual Detecting System for The Rotation Axis of Golf Ball (영상 기반 회전 골프공 무게중심 검출 시스템)

  • Hyun, Woong-Keun
    • The Journal of the Korea institute of electronic communication sciences
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    • v.14 no.2
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    • pp.411-416
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    • 2019
  • In this paper, we describe a measurement system based on vision for detecting the rotation axis of dimpled golf ball. Some golf balls have wrong rotation axis owing to bad production and scratch. A flying golf ball makes sliced or curved motion mainly to owing the wrong rotation axis of golf ball. Dimples of golf ball make a golf ball higher and more straight flying. When we hit a golf ball by driver or iron club, the dimpled ball flies straight and rotates as well. While the ball flying, the rotating axis of the ball convergence. And this makes the ball motion curved. If we hit a golf ball in direction of the rotation axis, the flying ball makes straight motion. In this paper, we develop a control system to detect convergence axis and time of flying golf ball based on vision system. To show validity of the developed system, We experimented several case for dimpled golf balls.

A Study of Compensatio of Thermal Displacement of the Ball Screw in CNC Lathe (CNC 선반에서 BALL ACREW의 열변위 보정에 관한 연구)

  • 홍성오;김병철
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.10a
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    • pp.181-186
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    • 1993
  • Thermal expansion of ball screw in the semi-closed loop type CNC LATHE introduces positioning errors directly along the travelling the axis. In this paper the thermal displacements of the ball screw were estimated by using macro variable. The estimated displacements of the ball screw were given to the ball screw of the CNC LATHE under the constant driving conditions were measured to examine the effectiveness of the compensation method. The results showed that thermal displacements of the ball screw could be maintained less then 6 .mu.m positioning accaracy while using this compensation.

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A Study on the Driving System Using Ball Screw (볼나사를 이용한 이송계에 관한 연구)

  • 이상조;남원우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.981-984
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    • 1995
  • The feed system using ball screw is constructed by ball screw, support bering and LM guide, and servo system for driving ball screw. AC servo motr drives ball screw which was connected by coupling. In this study, a new axial direction dynamic modeling of ball screw driving system was developed, and forced vibraition test using the impact hammer was experimented. The simulation result is compared with experimental result, which defines the reliability of mathematical modeling.

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Volumetric Error Measurement and Calibration of Coordinate Measuring Machines Using a Ball-bar Artifact (Ball-Bar Artifact를 이용한 CMM의 공간 오차 측정 및 분석)

  • 구상서;이응석
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2001.04a
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    • pp.143-148
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    • 2001
  • Volumetric error measurement and calibration of a coordinate measuring machine are studied by using a Ball-Bar artifact. Examples of the Ball-Bar design are shown using inbar materials and precision steel balls. Also, for the uncertainty error using the Ball-Bar is discussed. Method of Ball-Bar artifact and the analysis of the error vectors are proposed. Using the Ball-Bar data, we studied the method of volumetric errors ana]ysis of a coordinate measuring machine.

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Pulmonary Function Tests of Athletes (각종(各種) 운동선수(運動選手)의 폐기능검사성적(肺機能檢査成績))

  • Cho, Ching;Yoon, Pyung-Jin
    • The Korean Journal of Physiology
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    • v.15 no.1
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    • pp.45-51
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    • 1981
  • The aim of this study was to investigate the pulmonary function tests of athletes related to Running, Swimming, Cycle, Taekwando, Wrestling, Boxing, Yudo, Badminton, Base-ball, Soccer, Hand-ball, Basket-ball and Volley-ball. Subjects were 269 athletes from 18 to 22 years of age. They were college students and citizens. The results are as follows: 1) Frequency of breath: (cycles/min., $M{\pm}S.D$) Running shows $13{\pm}3.6$, Swimming $12{\pm}3.2$, Cycle $13{\pm}3.4$, Taekwondo $12{\pm}4.0$, Wrestling $14{\pm}2.5$, Boxing $15{\pm}4.5$, Yudo $13{\pm}3.2$, Badminton $14{\pm}5.7$, Base-ball $15{\pm}6.2$, Soccer $13{\pm}2.5$, Hand-ball $14{\pm}2.5$, Basket-ball $12{\pm}5.6$, Volley-ball $12{\pm}4.2$(Table 2, Fig. 1). 2) Vital capacity: (1, $M{\pm}S.D$) Running shows $4.29{\pm}0.634$, Swimming $4.30{\pm}0.608$, Cycle $4.08{\pm}0.718$, Taekwondo $4.32{\pm}0.595$, Wrestling $4.40{\pm}0.663$, Boxing $4.45{\pm}0.779$, Yudo $4.58{\pm}0.389$, Badminton $3.98{\pm}0.556$, Base-ball $3.99{\pm}0.617$, Soccer $4.42{\pm}0.728$, Hand-ball $4.23{\pm}0.397$, Basket-ball $4.28{\pm}0.426$, Volley-ball $4.60{\pm}0.620$(Table 2, Table 3, Fig. 2). 3) Tidal volume: (ml, $M{\pm}S.D$) Running shows $615{\pm}180$, Swimming $603{\pm}121$, Cycle $529{\pm}189$, Taekwondo $726{\pm}112$, Wrestling $512{\pm}90$, Boxing$622{\pm}134$, Yudo $583{\pm}89$, Badminton $672{\pm}121$, Base-ball $714{\pm}97$, Soccer $579{\pm}89$, Hand-ball $507{\pm}69$, Basket-ball $628{\pm}133$, Volley-ball $597{\pm}144$(Table 2, Fig.3). 4) Breath holding time : (sec., $M{\pm}S.D$) Running shows $64{\pm}18.8$, Swimming $81{\pm}23.0$, Cycle $54{\pm}13.6$, Taekwondo $55{\pm}11.8$, Wrestling $78{\pm}12.5$, Boxing $63{\pm}9.6$, Yudo $71{\pm}14.4$, Badminton $62{\pm}9.8$, Base-ball $58{\pm}8.9$, Soccer $65{\pm}10.9$, Hand-ball $66{\pm}7.6$, Basket-ball $62{\pm}8.8$, Volley-ball $57{\pm}13.4$(Table 2, Fig.4).

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Precision Measurement System forBall Screw Pitch Error (볼스크류 전구간 피치오차 측정시스템)

  • 박희재;김인기
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.10a
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    • pp.279-285
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    • 1993
  • This paper presents a precision automatic measuring system for ball screw Pitch. Ball screw is mounted on a precision indexing table, and the ball screw pitch is measured via magnetic scale, where the indexing and measurement are performed by a PC. For precision indexing of ball screw, direct driven motor is coupled to the designed dead and live centers; the performance of the centers are assessed with a precision master sylinder,such as radial motion,tilt motion, and axial motions. An error compensation model is constructed for the measurement system of ball screw pitch, where the error motions of indexing system as well as the scale measurement system are combined to give the measurement error for the ball screw. The developed system proposes an automated precision measurement system for manufacturers and users of ball screw.

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Shape Optimization of a Segment Ball Valve Using Metamodels

  • Lee, Jin-Hwan;Lee, Kwon-Hee
    • Journal of Navigation and Port Research
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    • v.34 no.7
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    • pp.553-558
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    • 2010
  • This study presents the optimization design process of a segment ball valve that involves the reduction of the flow resistance coefficient and the satisfaction of the strength requirement. Numerical analysis of fluid flow and structural analysis have been performed to predict the flow resistance coefficient and the maximum stress of a segment ball valve. In this study, a segment ball valve incorporating the advantages of a ball valve and a butterfly valve has been devised. In general, ball valves are installed in a pipe system where tight shut off is required. Butterfly valves having smaller end-to-end dimension than ball valve can be installed in narrow spaces in a pipe system. The metamodels for the shape design of a segment ball valve are built by the response surface method and the Kriging interpolation model.

A Study on Ball Screw Polishing Using Magnetic Assisted Polishing (자기연마법을 이용한 볼나사의 연마가공에 관한 연구)

  • 이용철;이응숙;최헌종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.43-47
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    • 1995
  • The ball screw is one of the important mechanical parts for the linear motion feeding systems. The usage of the ball screw has been growing in various industrial fields such as CNC machine tool, industrial robot and automated systems. Because of ever increasing demand for ball screws, increased accuracy and quality of the ball screw is needed,especially the surface roughness of the ball contact area in order to diminish noise and vibration. Therefore to improve the surface roughness of the area,we introduced magnetic assisted polishing which is one of the new potential polishing methods. In this study, diamond slurry and iron powder was used for magnetic assisted polishing of the ball bearing surface. This polishing process was experimentally confirmed to improve the surface roughness of the ball bearing.

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Curve Fitting with Recursive Ball Curve (Ball 곡선을 이용한 Fitting 알고리즘)

  • Lee, A-Ri;Choe, Yeong-Geun
    • The KIPS Transactions:PartA
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    • v.8A no.1
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    • pp.42-47
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    • 2001
  • In this paper, we present a curve fitting algorithm using a ball curve. Our algorithm is recursive method for fitting, which is not a traditional ball function but a continuous ball function. This algorithm consists of two steps. The first step, it is classified the composite corner points to joint points until selected from the given data set. The second step is the curve fitting. The basis function for curve fitting is use to ball function. Also, the weighted least square method, to insert knot, is an efficient method for piecewise ball curve and ball curve segments will be smoothly connected at all composit points. The proposed algorithm will be applied to represent image representation, like fonts, digital image and GIS.

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NRRO Analysis of HDD Ball Bearings with Geometric Imperfections (기하학적 형상오차를 갖는 정보저장기기용 볼베어링의 NRRO 해석)

  • 김영철;최상규;윤기찬
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.810-816
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    • 2001
  • In this paper, we theoretically analyzed the NRRO(the non-repeatable run-out) of a ball bearing with geometric imperfection. The quasi-static and dynamic analysis of a ball bearing was performed to calculate the displacement of shaft center caused by the form errors while the shaft is rotating. From consideration of the generating mechanism of NRRO, it is found that the waviness of one ball generates vibrations with nf$\sub$b/${\pm}$f$\sub$c/(where n is odd) components. Also it is confirmed that the outer race waviness of the order n = jZ${\pm}$1 generates vibration with jZf$\sub$c/ components. The form errors of ball bearing elements were precisely measured and NRRO of a ball bearing was calculated using the measured data. It is concluded that the ball bearings must has large ball number and small ball diameter to obtain low NRRO.

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