• 한국신뢰성학회지:신뢰성응용연구
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• 제13권3호
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• pp.217-227
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• 2013

Reliability growth is defined as the positive improvement in a reliability parameter over a period of time due to implementation of corrective actions to system design, operation or maintenance procedures, or the associated manufacturing process. In recent, the importance of reliability growth management has emerged in the military authority and industries. For effective application of reliability growth models, it is necessary to understand their characteristics and differences. This paper presents the concepts of reliability growth management and compares the features of reliability tracking and projection models centered on MIL-HDBK-189C for selecting the appropriate model for an one-shot system under development.

• 산업경영시스템학회지
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• 제19권39호
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• pp.255-264
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• 1996

This Paper presents a heuristic algorithm for machine-part group formation considering part production information (Production volume, roution sequence, unit operation time, facility size) in cellular manufacturing logistics system. In general, factory space is restricted within limited size when cells are located. A twofold heuristic algorithm is developed for considering factory space restrictions of located cells. The first phase is a aggregation procedure to minimize inter cell movement for satisfactoring space restriction. The second phase is a rearrangement procedure to maximize line balancing efficiency between machines within the cell and non assigned machine during first phase. Numerical example is presented to verify the efficiency of proposed algorithm.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2005년도 추계 학술대회
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• pp.155-159
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• 2005

High speed presses with high resolution in semiconductor lead frame manufacturing process are needed . But high speed operation accompanies mechanical vibration. therefore optimized kinematic structure to minimize vibration is required for a high speed press. And the growing competition in the industry asks a press with low cost, high speed, high resolution, and high pressing force, For this purpose a high speed press was modeled with 3D CAD solid modeling system and dynamic analysis were performed with CAE S/W for multibody dynamic analysis, Through these analyses a motor appropriate to a high speed press was selected and link structure for feeding system of the press was modified to reduce vibration. To perform this analysis working Model which is 2D kinematics and dynamic analysis software was used.

• Design & Manufacturing
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• 제13권1호
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• pp.36-41
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• 2019

A large plastic molding requires an injection molding with a large clamping force. However, it could not be prepared in the manufacturing at any time. In order to solve the problem, the injection molding analysis study was conducted on the back cover of 55 inch LED TV. The study compared the case of applying the existing flow system such as hot runner, the improvement of the hot runner lay-out and the precise control of the gate operation time, From the results of using the improved flow system, it was found that the welding and the clamping force were considerably improved as compared with before the improvement. In particular, the clamping force was reduced by 50% compared with before the improvement.

• 반도체디스플레이기술학회지
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• 제5권4호
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• pp.11-15
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• 2006

Expose equipment system that is used for manufacturing process of Flat Panel Display, is most important equipment in whole process. Expose equipment that is for making pattern of mask on substrate, consists of optical part, stage part and transport part. The stage is an important part that aligns mask and substrate for delivering pattern of mask to substrate exactly. In this paper, control system of expose stage that is able to use mask and substrate of diverse size, with PC controller using GUI interface instead of PLC control system. The existing PLC control system does not have the suitable structure for using mask of diverse size. GUI interface integration control system is based on PC. So it has the advantage of convenient use and active operation. We embodied PLC control system in integration control system based on PC, and verified utility possibility through the standard test course.

• International Journal of Automotive Technology
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• 제8권5호
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• pp.555-562
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• 2007

The Variable Valve Timing(VVT) system for high performance is a key technology used in newly developed engines. The system realizes higher torque, better fuel economy, and lower emissions by allowing an additional degree of freedom in valve timing during engine operation. In this study, a model-based control method is proposed to enable a fast and precise VVT control system that is robust with respect to manufacturing tolerances and aging. The VVT system is modeled by a third-order nonlinear state equation intended to account for nonlinearities of the system. Based on the model, a controller is designed for position control of the VVT system. The sliding mode theory is applied to controller design to overcome model uncertainties and unknown disturbances. The experimental results suggest that the proposed sliding mode controller is capable of improving tracking performance. In addition, the sliding mode controller is robust to battery voltage disturbance.

• 로봇학회논문지
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• 제19권3호
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• pp.311-317
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• 2024

Large-scale three-wheeled cleaning robots are utilized to clean large spaces such as warehouses and manufacturing plants where significant floor contamination occurs. Although there are autonomous cleaning robots, user-operated cleaning robots are often preferred because they are easy to repair and inexpensive. Therefore, workers have to spend extra time on cleaning, which reduces work efficiency. In this paper, we propose an autonomous driving system designed to automate the operation while maintaining the structure of existing cleaning robots. The contributions of this paper are as follows: 1) Hardware modules that control the driving and steering components. 2) A LiDAR-based autonomous driving system and path point generation system considering the mechanical characteristics of the cleaning robot. 3) The proposed system is implemented on an actual cleaning robot and driving tests are performed. As a result, when path planning is performed to cover the cleaning area, the average RMSE for each straight path is 0.0802 m, which is smaller than the minimum cleaning overlap of 0.3 m that occurs during the straight cleaning of the robot. This shows that the proposed system effectively covers the entire cleaning area.

• 기술사
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• 제28권3호
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• pp.121-134
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• 1995

본 논문에서는 생산 환경에서 MAP 네트워크에 접속된 여러 단위제어기기의 운영을 지원하기 위한 네트워크 관리 모듈을 설계하여 공정 모델 시스템에서 시범 운영하였다. 설계된 네트워크 모델의 안정성 해석을 위하여 토큰의 사용권의 공정한 배분과 시스템의 동작이 공정상의 특정한 시간 범위 내에 완료되어야 한다. 따라서 본 논문에서는 네트워크의 부하 파라미터로서 데이타 패킷의 크기와 노드의 수의 변화로 선정하여 이에 따른 네트워크 운영을 위한 토큰 로테이션 시간과 대기 시간의 대응된 변화값을 해석하였다. MAP 네트워크의 운영에서 데이타 패킷의 크기를 10바이트에서 100바이트까지 변화시킬 경우, 이에 대응한 토큰 로테이션 시간과 대기 시간의 변화는 주어진 조건하에서 10msec 이하의 값을 가진다. 따라서 프로그래머블 콘트를러 등의 단위 제어기기가 수십 msec 정도의 응답 하한선을 가지고 있으며 데이타 패킷의 크기는 50바이트를 넘지 않으므로 이의 실시간 처리에 충분히 적용 가능함을 알 수 있다.

• 한국기계가공학회지
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• 제16권2호
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• pp.7-15
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• 2017

Recently, an electricity sensor system has been installed and operated to prevent failures and accidents by identifying whether a transformer is normal in advance of failure. This electricity sensor system is able to both measure and monitor the transformer's power and voltage remotely and send information to a manager when unusual operation is discovered. However, a battery is required to operate power detection devices, and battery systems need ongoing management such as regular replacement. In addition, at a maintenance cost, occasional human resources and worker safety problems arise. Accordingly, we apply a linear electromagnetic generator using vibration energy from a transformer for an electric sensor system's drive in this research and we conduct optimal design to maximize the linear electromagnetic generator's power. We consider design variables using the provided design method from Process Integration, Automation, and Optimization (PIAnO), which is common tool from process integration and design optimization (PIDO). In addition, we analyze the experiment point from the design of the experiments using "MAXWELL," which is a common electromagnet analysis program. We then create an approximate model and conduct accuracy verification. Finally, we determine the optimal model that generates the maximum power using the proven approximate kriging model and evolutionary optimization algorithm, which we then confirm via simulation.

• 한국기계가공학회지
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• 제16권2호
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• pp.69-80
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• 2017

In or To use, manage, and preserve sustainable water resources for the current and future generations amid the threat of abnormal climate, it is necessary to establish a smart water grid system, the next-generation intelligent water management system. In this study, sensors, which make use of the five senses to watch, listen, and detect machine vibration, bearing temperature, machine operation sounds, current, voltage, and other symptoms that cannot be verified when the irrigation facilities are running, are used to establish various decision-making criteria appropriate to on-site situations. Based on such criteria, the unmanned conditions in the facilities were verified and analyzed. Existing technologies require on-site workers to check any defects caused by overloading of machines, which is the biggest constraining factor in the application of an unmanned control system for irrigation facilities. The new technology proposed in this study, on the other hand, allows for the unmanned analysis of the existence of machine vibration. This controls the decision-making process of any defect based on the analysis results, and necessary measures are taken automatically, resulting in improved reliability of the unmanned automation.