• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.181-183
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• 2008

반도체 칩 마운터는 PCB기판위에 칩을 마운팅 하는 장비로 짭은 시간내에 많은 양의 칩을 정확하게 마운팅 하기 위해 매우 빠른 가감속 운전과 정밀한 작업을 수행할 수 있는 선형전동기를 사용해 오고 있다. 고가임에도 빠른 응답특성, 높은 정밀도, 유지보수의 최소화 등 선형전동기가 가지고 있는 여러 가지 장점으로 인해 반도체를 포함한 LCD 및 기타 일반 산업에 까지 점진적으로 수요가 증가하고 있지만, 이동자에 전기자 권선을 가지고 있어 장거리 이송용으로 적합한 선형전동기의 경우 전원 케이블을 반복적으로 끌고 다녀야 하는 단점이 있어, 이런 문제점을 극복하기 위한 비접촉 방식의 전원 공급에 대해 많은 연구가 진행되고 있는 실정이다. 따라서 본 연구에서는 직병렬 공진 원리를 이용하여 움직이는 이동자의 전기자 권선에 비접촉으로 전원을 공급하는 전원 장치를 제안하며, LCD 자동 반송 장비인 스토커에 적용하여 특성을 분석하였다.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.3
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• pp.147-154
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• 2004

This paper presents a procedure for analysis and design of a fine positioning stage, which has many applications in industries for machine tools, semiconductor, LCD and so forth. The stage considered here is based on a single module with 3 axes which is composed of flexures hinges, piezoelectric actuators and their peripherals. Through a series of analysis, the structural analysis model is simplified as a rigid body(the moving part) and springs(the flexures hinges). An experimental design procedure is applied to determine the dimension of flexures hinges. A sensitivity analysis on the notch positions is also performed to obtain a guideline of fabrication accuracy for the stage. An actual fine stage is made and verified through an experiment on the dynamic characteristics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2604-2611
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• 2013

The Personal Rapid Transit(PRT) system has been highly interested in future transportation developments due to its on-demand and optimized door-to-door transport capability. However, the major impediments to the commercialization of PRT are the high cost for construction of infrastructures as opposed to the small transport capacity and difficulty in defining the role of PRT in building a balanced transportation system. In this study, the vertical transfer device for the PRT vehicle is developed to provide more flexible and better compatible urban mobility services between means of transportation, which is expected to meet particular demands in a particular environment. This apparatus was initially designed based on the basis of vertical circulating conveyors with steel chains, which is frequently used in logistics. Its advantages are capable of the non-stop loading and reduced head-way time. Most importantly, it was intensified by the additional idea to ensure the stable and reliable transfer of the PRT vehicle fully loaded with passengers. The 1/10-scale prototype was successfully tested to demonstrate a fundamental mechanism of vertical transfer and identify unexpected user requirements prior to a real manufacturing process.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.6
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• pp.511-518
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• 2013

To implement an automatic picking system (APS) in distribution center with high precision and high dynamics, this paper presents a design of a linear induction motor (LIM) drive and robust position controller based on integral variable structure control (IVSC) scheme. The force disturbance as well as the mechanical parameter variation such as the mass and friction coefficient gives a direct influence on the position control performance of APS. To guarantee a robust control performance in the presence of such uncertainty, a robust position controller is designed. A Simulink library is developed for the LIM model from the state equation. Through this model and comparative simulation based on Matlab - Simulink, it is proved that the proposed scheme has a robust control nature and is most suitable for APS.

• Journal of the Korea Society for Simulation
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• v.32 no.4
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• pp.11-18
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• 2023

This study analyzes the effect of a handshake location of an AS/RS with twin cranes for mixed-model production line at an automobile plant. Implementing a handshake operation has the advantage for preventing route interference between twin cranes that operate without crossing into each other's working areas. However the handshake operation requires additional unloading and loading processes to retrieve assembly parts beyond the handshake area. Therefore the decision regarding the handshake location is crucial to improve efficiency of storage and retrieval operations. Simulation results show that the handshake operation with the optimal handshake location reduces the average response time of storage requests to 87% compared to non-handshake operation.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.8
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• pp.906-912
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• 2012

This paper presents the new method for a six-degree-of-freedom (DOF) motion measurement and those dynamic characterizations in an ultraprecision linear stage using angle sensor-implemented grating interferometry. It consists of a diffractive optical element, a corner cube, four separate two-dimensional position sensitive detectors, four photodiodes and auxiliary optics components. From the previous study, it was confirmed that the proposed optical system could measure a six-DOF motion error in a linear stage. In this article, six-DOF motion dynamic characteristics of the stage were investigated through the step response and with respect to the conditions with a different speed of a slide table. As a result, the natural frequency and damping ratio according to a six-DOF direction was obtained. Also, it was seen that the speed of slide table had an significant effect on a six-DOF displacement motion, especially, X, which was considered as the effect of friction mechanism and local elastic mechanical deformation in a slide guide.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.3
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• pp.398-405
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• 2003

A fast response analyzer for measuring carbon dioxide concentration has been developed for transient characteristic and researches tested on internal combustion engine. The analyzer uses the well known NDIR(Non-Dispersive Infrared) method with miniaturized detection system, giving a time constant of approximately 30 microsecond, and sampling module consists of capillary tube. Since the transit time and the time constant of the sampling system depend on the sampling conditions, it is necessary to investigate the characteristics of sampling system before applied to exhaust gas measurement in engine. A unique method was designed to study the influence of the diameter of transfer sample line and operating conditions of the FRNDIR on transit time and time constant. A database of transit time and time constant was built up for different measured and simulated pressure conditions. The database can be used for correcting eventual $CO_2$ concentration measurement.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.99-104
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• 2015

Today the most efficient way to transport the natural gas is carried via the liquid. In order to liquefy the natural gas to be cooled to $-160^{\circ}C$ or less. Cooling method has a number of different ways. In this paper, we studied control method for the representative liquefaction process, C3MR. Natural gas liquefaction control is a tool that can maintain the quality of natural gas is a means to ensure stable operation. Analyzing the C3MR process, and select the control parameters for the control valve. We find control structure for mixed refrigerant cycle through the step response. A control result obtained through the dynamic simulation arbitrarily given a disturbance was found to maintain a steady-state results.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.1
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• pp.7-14
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• 2015

To implement an automatic picking system (APS) in distribution center with high precision and high dynamics, this paper presents a high gain observer-based robust speed controller design for a linear induction motor (LIM) drive. The force disturbance as well as the mechanical parameter variations such as the mass and friction coefficient gives a direct influence on the speed control performance of APS. To guarantee a robust control performance, the system uncertainty caused by the force disturbance and mechanical parameter variations is estimated through a high gain disturbance observer and compensated by a feedforward manner. While a time-varying disturbance due to the mass variation can not be effectively compensated by using the conventional disturbance observer, the proposed scheme shows a robust performance in the presence of such uncertainty. A Simulink library has been developed for the LIM model from the state equation. Through comparative simulations based on Matlab - Simulink, it is proved that the proposed scheme has a robust control nature and is most suitable for APS.

• Fire Science and Engineering
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• v.30 no.1
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• pp.130-137
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• 2016

The purpose of this study is to investigate the circumstances surrounding collisions involving ambulances with an aim to improving the safe operation of emergency services. Collisions are relatively common within paramedic emergency services. We analyzed the time, injury site, and any other specific factors of 908 collisions occurring within four cities. Within our study 29.6% of paramedics have been involved in accidents while responding to an emergency call, with the main cause of the accident being signal violation (35.7%), and is the other party's negligence (22.2%). 92.1% of these accidents occurred while the emergency lights were being operated. XX% of accidents took place in the afternoon, while xx% took place within the hours of xx:xx and xx:xx, during which time there is generally lower levels of traffic, which can cause severe brain and neck damage of 14.4% but the other part is 62.1%. (Ed note; this is not clear at all. 14.4% of collisions resulted in severe head and neck injuries, while 23.5% of collisions resulted in no injury. According to the respondents, defensive driving (xx%), observance of traffic laws (xx%), safe driving habits (xx%)to paramedics were the most critical factors in evading collision. Signal passes were identified as the most common cause of collision (70.1%). Although the majority of collisions occurred while the emergency lights were operational, the damage can cause severe damage at the time of accident occurred.