• 드라이브 ㆍ 컨트롤
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• 제19권1호
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• pp.69-75
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• 2022

This study aimed to develop solutions for the intermittent performance deterioration of self-propelled spinach harvesters through analysis model. The study was conducted in the following manner. First, changes in performance deterioration and surplus flow, which result from oil temperature changes, were analyzed by simulating actual sequential harvesting movements, which involve driving with actuators operated simultaneously, by analysis model developed in a previous study. Second, fundamental solutions for surplus flow problems were presented. Third, the solutions were applied to a virtual environment to present their practicality and quantitative effects. The two solutions based on the study results were as follows. First, a closed center-type directional control valve was applied to the hydraulic circuit. Second, an unloading system was set up through an on-off solenoid valve.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.447-452
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• 2001

An automated system is developed to perform fatigue crack growth tests under constant effective stress intensity factor range ${\Delta}K_{eff}$. In the system, crack length and crack opening load are measured in real-time by using the unloading elastic compliance method. The system consists of two personal computers, an analogue electrical subtraction circuit, a stepping motor, a stepping motor driver, a PIO board, and the application software used to integrate the whole system. The performance of the developed system was tested and discussed performing constant ${\Delta}K_{eff}$ crack growth tests on a CT specimen of 7075-T6 aluminum alloy. The performance of the system is found to be strongly dependent on the accuracy of measurements of crack opening load. Besides constant ${\Delta}K_{eff}$ testing, the system is expected to be successfully applied for automation of various fatigue tests.

• 반도체디스플레이기술학회지
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• 제4권4호
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• pp.27-31
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• 2005

This article contains the development of FPC bonder that used for repair or trial product. Nowadays, in FPO module process (including PDP) accept the thermo-compress bonding method when attach FPC(Flexible Printed Circuit Board), TCP(Tape Carrier Package) and COF(Chip on the FPC) by ACF(Anisotropic Conductive Film). This system consists of ACF attachment part, pre-bonding part, main bonding part, loading / unloading part. This composition is a stand-alone system, not an in-line system. Hereafter, this composition should be developing into in-line system in all area of FPD industry.

• 한국산학기술학회논문지
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• 제14권2호
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• pp.554-560
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• 2013

본 연구에서는 양쪽 대칭으로 지지할 수 있는 쉴드캔 클립을 제안하며, 그 특징은 장착과 탈착의 하중을 일정하게 하고 납땜 부위의 평판도를 유지 할 수 있도록 개발하였다. 또한 인쇄회로기판에 부착 고정되는 베이스부 및 쉴드캔의 측벽을 집게 형태로 집을 수 있도록 하는 클립부로 구성되며, 클립부 중앙을 절단하여 2군데를 지지 할 수 있게 이루어진다. 또한 넓어진 베이스부와 인쇄회로기판 사이에 납땜이 잘될 수 있도록 오목한 홈을 만들었다. 연구절차는 우선 메커니즘을 설정하고 구조해석 및 진동모드 해석을 수행하여 설계변수를 확정한 후, 제품을 설계하였다. 제조를 위한 전용기를 개발한 후 시제품을 제작하여 성능 평가 후 해석값과 비교 분석하였다.

• 드라이브 ㆍ 컨트롤
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• 제20권4호
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• pp.17-26
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• 2023

A forklift is an industrial vehicle that lifts or transports heavy objects using a hydraulically operated fork, and is equipped with an automatic transmission for the convenience of repetitive transportation, loading, and unloading work. The Transmission Control Unit (TCU) is a key component in charge of the shift control function of an automatic transmission. It consists of an electric circuit with an input/output signal interface function and firmware running on a microcontroller. To develop TCU firmware, the development process of shifting algorithm design, firmware programming, verification test, and performance improvement must be repeated. A simulator is a device that simulates a mechanical system having dynamic characteristics in real time and simulates various sensor signals installed in the system. The embedded transmission simulator is a simulator that is embedded in the TCU firmware. information related to the mechanical system that is necessary for TCU normal operation. In this study, an embedded transmission simulator applied to the originally developed forklift TCU firmware was designed and used to verify various forklift shift control algorithms.

• 한국기계가공학회지
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• 제14권4호
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• pp.151-159
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• 2015

In this study, we developed an automated contact-type thickness measurement machine that continuously and precisely measures the thickness of a PCB module product using multi-LVDT sensors. The system contains a measurement part to automatically measure the thickness in real time according to the set conditions with an alignment supply unit and unloading unit to separate OK and NG products. The sensors were calibrated before assembly in the measuring machine, and precision and accuracy performance tests were also performed to reduce uncertainty errors in the measurement machine. In the calibration test, the precision errors of the LVDT sensor were determined to be $1-3{\mu}m$ as 0.1% at the measuring range. A measurement error of 0.8 mm and 1.0 mm thickness test standards were found to be $1{\mu}m$ and $4{\mu}m$, and the standard deviations of two 1.0 mm products were measured as $14{\mu}m$ and $8{\mu}m$, respectively. In the measurement system analysis, the accuracies of test PCB standards were found to be $2{\mu}m$ and $3{\mu}m$, respectively. From the results of gage repeatability and reproducibility (R & R) crossed, we found that the machine is suitable for the measurement and process control in the mass production line as 7.92% of total gage R & R and in seven distinct categories. The maximum operating speed was limited at 13 pcs/min, showing a value good enough to measure.