• Title, Summary, Keyword: Mechanism

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Mechanism Analysis and Optimal Desing of feeding Mechanism of Industrial 2 needle Sewing Mechine (공업용 2본침 침송 재봉기의 이송 메카니즘 해석 및 최적설계)

  • 이장용;전경진
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.803-807
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    • 1996
  • In this paper, we perform a mechanism anlysis and optyimal designof the feeding system in a industrial sewing machine. Sewing machines are classified by the transfer mechanism as (1) transferred by feed dog only (2) transferred by feed dog and needle (3) transferred by feed dog, needle and pressure bar. We took the dewing machine classified as (2) which is more efficient in transferring the clothes than the machine classified as (1). In analyzing the mechanism, we divide the feeding mechanism as feed dog mechanism and needle bar mechanism. The two mechanisms are connected with each other kinematically because the clothes are transferred by needle and feed dog simultaneously and stitched by needle which pass through the feed dog in every stitchcycle. We define good stitch as coincidence of stitch between the forward and reverse motion of feeding. And we optimize feeding mechanism for that purpose. It is illustrated that stitching performance of the optimized mechanism is compared to original feeding mechanism.

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Generation of a skeletal mechanism of coal combustion based on the chemical pathway analysis

  • Ahn, Seongyool;Watanabe, Hiroaki;Shoji, Tetsuya;Umemoto, Satoshi;Tnno, Kenji
    • 한국연소학회:학술대회논문집
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    • pp.5-7
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    • 2014
  • A skeletal mechanism of coal combustion was derived from a detailed coal combustion kinetic mechanism through an importance analysis of chemical pathways. The reduction process consists of roughly two parts. The first process is performed based on a connectivity analysis between species. In this process, DRGEPSA is chosen for reduction process. Strongly connected species and related reactions from the important species set as start species by the operator are sorted into the reduced mechanism. About 70% of species and reactions can be removed with a limited accuracy loss. Subsequently the second reduction process, CSP, is performed. This method focuses on an importance of each reaction and can reduce a volume of mechanism appropriately. Through these analyses, a skeletal mechanism is generated that is including 65 species and 150 reactions. The generated skeletal mechanism is verified through a comparison with the detailed mechanism in the homogeneous reactor model of CHEMKIN-PRO under wide range of conditions. The generated mechanism can give an advantage in the analysis of coal combustion characteristics in detail in large scale simulations such as LES and DNS.

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Functional Verification of Engineering Model of Non-explosive Shockless Holding and Release Mechanism Using Heating Wire Cutting Method (열선 절단 방식을 적용한 비폭발식 무충격 구속분리장치 EM의 기능검증)

  • Oh, Hyun-Ung;Jeon, Su-Hyeon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.5
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    • pp.401-406
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    • 2013
  • Non-explosive shockless holding and release mechanism for a nano class small satellite application has been proposed and investigated. The great advantages of the mechanism are a much lower shock level and larger constraint force than the conventional mechanism using pyro and the heating wire cutting mechanism which has been generally applied to the cube satellite program. To investigate the effectiveness of the mechanism design, EM mechanism was developed and tested to verify the basic function of the mechanism. The test results indicate that the proposed mechanism is well functioning as the mechanism design intends.

Study on quasi-static crawling system using a four bar mechanism (4절 메카니즘을 이용한 준정적 포복 시스템에 관한 연구)

  • 전용호;송낙윤;김희국
    • 제어로봇시스템학회:학술대회논문집
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    • pp.924-927
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    • 1996
  • In this work, we investigate the quasi-static crawling of the four-bar mechanism. Since the crawling of the mechanism is based on sliding of contact points of the mechanism with the ground, interaction forces and friction forces at contact points of the mechanism with the ground should be computed. For this purpuse, we introduce the concept of imaginary joints to find these forces. Therefore, we are able to treat the closed mechanism as a serial one. Also, sliding conditions of the mechanism in quasi-static equilibrium are examined. Lastly, the required torques for the mechanism to crawl with respect to various configurations of the mechanism but with a fixed ground friction are investigated.

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Feasible Design Area of 4 Bar Input Crank for 3 Position Synthesis of Watt-II 6 Bar Mechanism (6 절기구 응용을 위한 3 위치 운동 생성용 4절 가구 합성을 위한 입력 크랭크의 합당해 영역)

  • 범진환
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.3
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    • pp.88-98
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    • 1998
  • In many automatization applications, a rigid body is required to go forward and backward repeatedly through a set of given position/orientations precisely while a crank is rotated. Such a motion can be generated by 6 bar mechanism adding a dyad to a 4 bar mechanism. If this is the case for 3 position synthesis of the 4 bar mechanism, the feasible solution area for designing the 4 bar mechanism will be limited over the general solution area. This paper proposes a procedure to synthesize 4 bar mechanism to be used to generate the required motion. It is found that the only input crank of the 4 bar mechanism should be limited to satisfy the condition. And the feasible design area for the circle point/ center point of the input crank is identified so that design of the undesired mechanism could be avoided. The method is tested and the results are shown.

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A Study on Component Modular Approach for Type Synthesis Automation of Mechanism (기구 형태설계 자동화를 위한 컴포넌트 모듈 접근법에 관한 연구)

  • 김봉주;윤호업;신중호;권순만;장세원
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1270-1273
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    • 2004
  • The mechanism design is synthesis of suitable mechanism which can be output motions about input motions. That has generally two steps which are the type synthesis and the dimensional synthesis. And required mechanism analysis step for confirming middle or final result. The type synthesis is definition of mechanism type which required aim and the dimensional synthesis is calculation of dimension about defined type mechanism. The type synthesis of mechanism is included qualitative design field which isn't defined systematic design method. especially, the most difficult step for mechanism design automation. In this paper proposed the component modular design method which is figured mechanism types automate with component modules using component modular approach. And develop CAD(Computer Aided Program) program for application.

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Analysis of Multiple Displacement Magnification Mechanism in Ultraprecision Nano Stage (초정밀 나노 스테이지에서의 다중 변위 확대 기구 해석)

  • Min K.S.;Choi W.C.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1273-1276
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    • 2005
  • A displacement magnification mechanism is usually employed in a nano-positioning stage to achieve a large stage motion. A lever mechanism is the most widely used displacement magnifying mechanism. For more large stage motion, double or multiple lever mechanisms can be used. In this case, a more accurate analysis model is needed. This study proposes a more reasonable analysis model for a multiple lever mechanism based on the single lever mechanism model. This paper describes that the high equivalent stiffness of the lever is the most important factor reducing the magnification ratio of the lever mechanism through increasing the deflection of the link and including the axial displacement of the pivot.

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Quasi-Static Crawling System Using a Four Bar Mechanism (4절 메커니즘을 이용한 준정적 포복 시스템)

  • Kim, Hae-Soo;Kim, Min-Gun;Yim, Nam-Sik;Kim, Wheekuk;Yi, Byung-Ju
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.3
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    • pp.226-232
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    • 2002
  • In this work, the quasi-static crawling of the four-bar mechanism is investigated. Since the crawling of the mechanism is based on sliding of contact points of the mechanism with the ground, interaction forces and friction forces at contact points of the mechanism with the ground should be computed. For this purpose, we introduce the concept of imaginary joints to find these forces and treat the closed mechanism as a serial one. Lastly, the required torques for the mechanism to crawl with respect to various configurations of the mechanism on a flat ground with uniform friction coefficient, based on sliding conditions of the mechanism in quasi-static equilibrium, are investigated.

A Forward Closed-Form Position Solution, Kinematic Analysis And Implementation of a Translational 3-DOF Parallel Mechanism Formed by Constraining a Stewart Platform Structure (스트워트 플랫폼 구조를 구속하여 얻어지는 병진형 3 자유도 병렬 메커니즘의 정위치 해석해와 기구학 해석 및 구현)

  • Shin Dong-Min;Chung Jae-Heon;Oh Se-Min;Yi Byung-Ju;Kim Whee-Kuk
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.10
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    • pp.1035-1043
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    • 2006
  • In this study, a translational 3-DOF parallel mechanism formed by constraining the Stewart Platform Mechanism is investigated. The translational 3-DOF parallel mechanism has three struts(3-UPS type serial subchains) and in addition, has a PPP type serial subchain in the middle of the mechanism. Firstly, the closed-form forward and reverse position solutions are derived for this mechanism. And analysis on kinematic characteristics using isotropic index of the Jacobian is conducted to examine effects of design parameters for the mechanism. Lastly, a prototype mechanism is implemented and the kinematic performance of the translational 3-DOF parallel mechanism was verified through experimental work.

Implementation of a New Parallel Spherical 3-Degree-of-Freedom Mechanism With Excellent Kinematic Characteristics (우수한 기구학 특성을 가지는 새로운 병렬형 구형 3자유도 메커니즘의 구현)

  • 이석희;김희국;오세민;이병주
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.299-303
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    • 2004
  • In our pervious paper, a new parallel-type spherical 3-degree-of-freedom mechanism consisting of a two-degree-of-freedom parallel module and a serial RRR subchain was proposed[1]. In this paper, its improved version is suggested and implemented. Differently from the previous 3-dof spherical mechanism, gear chains are incorporated into the current version of the mechanism to drive the distal revolute joint of the serial subchain from the base of the mechanism and in fact, the modification significantly improves kinematic characteristics of the mechanism within its workspace. Firstly, after a brief description on its structure, the closed-form solutions of both the forward and the reverse position analysis are derived. Secondly, the first-order kinematic model of the mechanism for the inputs which are assumed to be located at the base is derived. Thirdly, through the simulations of the kinematic analysis via. kinematic isotropic index, it is confirmed that the mechanism has much more improved isotropic properties throughout the workspace of the mechanism than the previous mechanism in [1]. Lastly, the proposed mechanism is implemented to verify the results from this analysis.

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