• Title, Summary, Keyword: 캠 함수

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A Study on the Selection Displacement Curve Function for Cam Design of Double Cam Type Beating Mechanism Based on Cam Mechanism Simulation (캠 기구의 시뮬레이션을 이용한 더블캠 방식 바디침 기구의 캠 설계를 위한 변위선도함수 선정에 관한 연구)

  • 김종수;윤호업
    • Textile Science and Engineering
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    • v.39 no.6
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    • pp.790-803
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    • 2002
  • A beating motion is one of the main motions of the rapier loom. The beating motion locates yarn to a desired position after weft insertion motion. There are two kinds of mechanism for beating motion. One is crank lever type and the other is double cam type. Crank lever type usually used low speed rapier loom. In other hand double cam type used high speed rapier loom. Cam part in double cam type beating mechanism is very important. Cam design starts at displacement curve design. This study investigated four different displacement curves selected from various kinds of displacement curve functions. Thus this paper proposed how to select optimized displacement curve function for double cam type beating mechanism of high speed rapier loom using cam simulation. And then, presents the comparable data of pressure angle, cam contact force and driving torque per each of displacement curve to determine the optimized displacement curve function.

Synthesis of Optimum CAM Curve by Cubic Spline (Cubic Spline을 사용한 최적 캠곡선의 합성)

  • 손태영;양민양
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.5
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    • pp.1168-1175
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    • 1995
  • The application of cubic spline is presented for basic curve (DRD motion) of cam motion. The purpose of this paper is to achieve better dynamic characteristics than general cam curves. A cubic spline is a piecewise function that is continuous in displacement, velocity and acceleration. The best cam curve is obtained by changing the weights of the object function. So the method can be used to any machine system case by case. For the proposed object function, the result has improved all characteristics such as velocity, acceleration and jerk compared with that of the modified sine curve.

Cam Design of Packer Holder in Egg Grading Machine (계란선별기 파커홀더 캠 개발)

  • Lee, Jang-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.10
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    • pp.897-904
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    • 2008
  • Egg grading machine is used in poultry raising industry to classify eggs by their weight and to pack up them. Packer holder mechanism is a main part of the egg grading machine, of which role is to take eggs fallen from conveyor belt, and afterward to transfer eggs vertically to mold tray. The vertical motion of packer holder is usually driven by slider-crank mechanism or cam. This paper describes development of the cam in packer holder based on kinematic analysis of packer holder mechanism and measurement of acceleration and noise of the cam to verify performance of it. Several cams that are designed and manufactured by the author of this paper according to different design specification are compared to determine the best solution for egg transfer in the packer holder mechanism.

Control of Crowning Using Residual Stress induced by the Difference of Tehermal Expansion Between Ceramic and Carbon Steel in Ceramic Cam Follower (열팽창계수차에 기인된 잔류응력을 이용한 세라믹 캠 팔로우어의 크라우닝 제어)

  • Choe, Yeong-Min;Lee, Jae-Do;No, Gwang-Su
    • Korean Journal of Materials Research
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    • v.10 no.10
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    • pp.703-708
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    • 2000
  • As the engine design changes to get high efficiency and performance of commercial diesel engine, surface w wear of the earn follower becomes an important issue as applied load increasing at the contact face between cam follower and cam. We developed the ceramic cam follower made of sili$\infty$n nitride ceramic which was more wear resistant than the cast iron or sintered metal cam follower. Ceramic cam follower was made by direct brazing of thin ceramic disk to steel body using an active brazing alloy without the interlayer. In-situ crowning(R), resulted from the difference of thermal expansion coefficient between ceramic and carbon steel after direct brazing without any stress-relieving inter]ayer, could be controlled. When a earbon steel was heated above $A_{c1}$ point and then c$\infty$led, the expansion curve represented a hysteresis. Appropriate crowning was achieved below the $A_{c1}$ point(about $723^{\circ}C$) and crowning increased with brazing temperature exponentially above the $A_{c1}$ point. Optimum brazing temperature range was from 700 to $720^{\circ}C$. We developed successfully the ceramic cam follower having appropriate crowning and being inexpensive. Also we could successfully control the crowning of ceramic earn follower by hysteresis behavior of thermal expansion of earbon steel during direct brazing process.

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Analysis of Stress Concentration Problems Using Moving Least Squares Finite Difference Method(I) : Formulation for Solid Mechanics Problem (이동최소제곱 유한차분법을 이용한 응력집중문제 해석(I) : 고체문제의 정식화)

  • Yoon, Young-Cheol;Kim, Hyo-Jin;Kim, Dong-Jo;Liu, Wing Kam;Belytschko, Ted;Lee, Sang-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.4
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    • pp.493-499
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    • 2007
  • The Taylor expansion expresses a differentiable function and its coefficients provide good approximations for the given function and its derivatives. In this study, m-th order Taylor Polynomial is constructed and the coefficients are computed by the Moving Least Squares method. The coefficients are applied to the governing partial differential equation for solid problems including crack problems. The discrete system of difference equations are set up based on the concept of point collocation. The developed method effectively overcomes the shortcomings of the finite difference method which is dependent of the grid structure and has no approximation function, and the Galerkin-based meshfree method which involves time-consuming integration of weak form and differentiation of the shape function and cumbersome treatment of essential boundary.

A Study on Reverse Design of Cam Mechanism using NURBS (NURBS를 이용한 캠 기구의 역설계에 관한 연구)

  • 김상진;신중호;김대원;윤호업
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.920-924
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    • 2002
  • This paper presents the reverse design of a cam mechanism using NURBS(Nonuniform Rational B-spline curve). Cam is very difficult to make the accurate shape on the design and the manufacture. Because the cam shape is commonly made in order to move in special functions. The reverse design can be used to check accuracy between the designed data and the manufactured data of the cam shape and also reproduce the cam without the design data. The reverse design procedures consist of motion analysis and curve fitting. The motion analysis is used the central difference method and the relative velocity method to find the displacement and velocity. The curve fitting is used NURBS to develope the whole curve. The central difference method is derived in the 3 dimensional space.

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A Vision-based Electronic Chalk System by Using Infrared Light (적외선을 이용한 카메라 기반의 전자 분필 시스템)

  • Kim, Ji-Ae;Park, So-Yeon;Lee, Seon-A;Choe, Hye-Yeong;Lee, Ui-Cheol;Hwang, Min-Cheol
    • Proceedings of the Korean Society for Emotion and Sensibility Conference
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    • pp.249-252
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    • 2009
  • 본 연구는 화면전환 및 필기 등의 프레젠테이션을 편리하게 제어 할 수 있는 시스템을 구현하고자 한다. 카메라를 이용한 컴퓨터 비전 분야에서 주변의 조명 환경의 영향을 적게 받는 적외선을 이용한 연구가 활발하게 진행되고 있다. 제안하는 방법에서는 USB(Universal Serial Bus) 타입의 카메라를 적외선 환경에 맞게 개조하고, 이를 이용하여 적외선 LED(Light Emitting Diode)를 이용한 전자 분필 영상을 취득하여, 실시간으로 전자 분필의 위치를 검출한다. 검출된 영역은 사전에 사용자가 설정한 '필기 가능 영역'과 변형 함수에 기반하여, 실제 모니터 좌표로 사상되어 화면에 표시되게 된다. 제안하는 시스템은 저렴한 가격의 웹 캠과 적외선 조명 이외에는 별도의 장비가 필요하지 않으면서도, 대형 스크린을 터치 방식으로 활용할 수 있다는 장점을 가진다. 실험 결과, 계산된 모니터 좌표와 사용자가 의도한 위치간의 평균 RMS(Root Mean Square) 오차는 약 15픽셀로 나타나서, 글씨를 필기하고 화면의 특정 부분을 강조하기 위한 활용이 가능함을 확인할 수 있었다.

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Aerodynamic Design Optimization of Airfoils for WIG Craft Using Response Surface Method (반응표면법을 이용한 지면효과익기 익형의 공력 설계최적화)

  • Kim, Yang-Joon;Joh, Chang-Yeol
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.5
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    • pp.18-27
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    • 2005
  • Airfoils with improved longitudinal static stability were designed for a WIG craft through aerodynamic design optimization. The response surface method is coupled with NURBS-based shape functions and Navier-Stokes flow analysis. The procedure runs in the network-distributed design framework of commercial-code based automated design capability to enhance computational efficiency and robustness.Lift maximization design maintaining similar static margin to a DHMTU airfoil successfully produced a new airfoil shape characterized by pronounced front-loading and the well-known reflexed aft-camber line. Another airfoil design of lower variation in pitching moment during take-off showed weakened front-loaded characteristics and hence decreased lift slightly. Investigations using the present design methodology on an existing optimization result based on potential flow analysis and NACA-type geometry generation demonstrated significance of carrying various geometry generations and more realistic flow analysis with optimization.