• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.54-63
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• 2022

Among the various industrial robots, palletizing robots have received particular attention because of their higher productivity in accordance with technological progress. When designing a palletizing robot, the main components, such as the servo motors and reducers, should be properly selected to ensure its performance. In this study, a practical method for selecting the motors and reducers of a robot was proposed by performing the dynamic analysis of rigid-flexible multibody systems using ANSYS and ADAMS. In the first step, the links and frames were selected based on the structural analysis results obtained from ANSYS. Subsequently, a modal neutral file (MNF) with information on the flexible body was generated from the links and frames using modal analysis through ANSYS and APDL commands. Through a dynamic analysis of the flexible bodies, the specifications of the major components were finally determined by considering the required torque and power. To verify the effectiveness of the proposed method, the analysis results were compared with those of a rigid-body model. The comparison showed that rigid-flexible multibody dynamic analysis is much more useful than rigid body analysis, particularly for movements heavily influenced by gravity.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.2
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• pp.117-122
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• 2014

A novel method to reduce the vibration of drum type washing machine is proposed. Recently, as the capacity of the drum-type washing machine gets expanded and its washing performance is improved, its market share is increasing in the whole world. But, the capacity of washing machine is limited because of door size and built-in washing machine size. The vibration of washing machine is caused by unbalanced cloths in high spining drum, and the displacement of tub is maximized at transient range about 3 Hz(180 rpm). Previous researches were concerned about steady-state vibration in spinning. In this study, concerned about transient vibration and the displacement of tub is decreased by using gyroscope system. Mutibody dynamic model of washing machine include gyroscope is designed and the vibration of tub have been reduced by 44.7 % over original.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.97-102
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• 2008

The vibration of a vehicle, which is caused by and transmitted from the engine, has significant effect on the ride comfort and the dynamic characteristics of the engine mount system have direct influence on the vibration and noise of the vehicle. This paper examines the body shake caused by the engine excitation force on engine key on/off of a medium truck by experiment and simulation. The analysis model consists of the engine, a body including the frame, front and rear suspensions and tires. The force element between the body and the suspension is modeled as a combination of a suspension spring and a damper. The engine shake obtained from the experiment was compared with the result of the computer simulation, and by using the verified computer model, parametric study of the body shake on engine key on/off is performed with changing the stiffness of an engine mount rubber, the engine mount angle, and the position of engine mounts.

• Journal of Aerospace System Engineering
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• v.12 no.1
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• pp.17-26
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• 2018

The interaction model between variable-speed control moment gyros and a satellite has been studied based on the multi-body dynamics. Using the interaction model, we could obtain data for the design of VCMG motors and the strength design of structure. The interaction effects of flexible modules such as solar panels were included. Flexible modes are excited by the satellite's maneuver, and these modes cause perturbations in the satellite attitude. We developed a simulation program by Modelica and verified the proposed model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.166-172
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• 1997

In order to find out relationship between hit probability and gun firing of a moving tank, a turret and flexible gun system model has been developed using the recursive flexible multibody dynamics. For a firing simulation model, nodal coordinates for a finite element model of a flexible gun have been employed to include traverse loads to the gun tube due to moving bullet and ballistic pressure. Modal coordinates are also used to represent the motion induced gun vibration before a firing occurs. An efficient switching technique from modal equations to nodal equations has been introduced for an entire gun firing simulation with rotating turret.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.422-427
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• 2001

The component mode synthesis method allows the elastic deformation of each component in the flexible multibody system by a sum of modes and modal coordinates. This paper focuses on the selection of boundary conditions and deformation modes for redundantly constrained flexible components in mechanical system dynamics. The result of a flexible body dynamic analysis with only normal modes is used to identify proper boundary conditions of a static modes and a desired set of static modes which will be used in the final model. A simple four bar mechanism is used to explain the procedure and a space satellite with solar panels is analyzed using the proposed method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.3
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• pp.303-311
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• 2013

This research deals with the analysis and design of a driving mechanism for an automatic pneumatic drug injector, which can precisely control the injection volume using a relatively simple friction-driven mechanism, without any complicated control system. Through a dynamic analysis, the effects of the design parameters of the driving mechanism associated with the geometry, spring stiffness, and fiction are analyzed, and the results are reflected in a proto-type drug injector design, which is under development for mass production. A test is performed to assess the durability of the mechanism for up to one million operations, and comparison of its displacement after one million operations, verifies the mechanism's durability.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.74-74
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• 2017

밀식파종 묘 이앙 시스템은 벼농사 생력화를 위한 재배법으로 비용 및 노동력을 획기적으로 줄일 수 있어 시간과 잉여 공간의 유효 활용을 통해 영농 규모의 확대로 인한 농업의 경쟁력을 높일 수 있다. 하지만 밀식 파종한 육묘를 관행과 동일한 1개 소당 3~4주 이앙 가능한 식부부 개발은 미흡한 실정이다. 밀식 파종한 육묘를 기존 이앙기로 이앙작업을 할 경우, 1개 소당 이앙되는 양이 많아져, 벼 생육을 저하 시키는 요인이 된다. 이러한 부분을 해결하기 위해서는 이앙 작업에 직접적으로 영향을 주는 이앙기식부부의 로터케이스, 이앙암을 분석하여 밀식파종 묘에 적용할 수 있는 기술이 필요한 실정이다. 본 연구에서는 식부부의 로터케이스, 이앙암을 3D 스캐너를 활용하여 스캐닝 작업을 한 뒤 역설계를 통하여 도면화 작업을 실시하여 식부부 궤적 분석을 실시하였다. 분석은 다물체 동역학 해석 프로그램인 Recurdyn(V8R4, Functionbay)을 활용하여 진행하였다. 분석결과, 식부부에 위치하는 이앙집게의 형상 및 로터케이스의 기어 배열에 따라 식부부가 형성하는 궤적의 형태가 달라지는 것을 확인 할 수 있었다. 이러한 부분은 밀식파종 묘에 적합한 궤적 분석 및 현장 필드 실험에 필요한 기초자료로 활용하고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.2
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• pp.330-340
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• 2009

A naval shipboard inevitably movies in a pitch and roll direction under the influence of wave and wind in the sea. As a result, the shipboard gets in a continuous turning motion back/front and right/left. And the shipboard is also constantly exposed to many different kinds of disturbance signals including the vibrations of various frequencies from the internal equipments and their vibrations, strong waves, and impact from explosion. This paper formulates multi-body dynamic models similar to an actual system and simulates the pitch/roll positions of a 2-axes gimbals with PI controller for consecutive behavior of a naval shipboard including disturbance.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.46-46
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• 2018

메모리 소자의 수요가 데스크톱 컴퓨터의 정체와 모바일 기기의 폭발적인 증가로 NAND flash 메모리의 고집적화로 이어져서 3차원 집적 기술의 고도화가 중요한 요소가 되고 있다. 1 mm 정도의 얇은 웨이퍼 상에 만들어지는 메모리 소자는 실제 두께는 몇 마이크로미터 되지 않는다. 수직방향으로 여러 장의 웨이퍼를 연결하면 폭 방향으로 이미 거의 한계에 도달해있는 크기 축소(shrinking) 기술에 의지 하지 않고서도 메모리 소자의 용량을 증대 시킬 수 있다. CPU, AP등의 논리 연산 소자의 경우에는 발열 문제로 3D stacking 기술의 구현이 쉽지 않지만 메모리 소자의 경우에는 저 전력화를 통해서 실용화가 시작되었다. 스마트폰, 휴대용 보조 저장 매체(USB memory, SSD)등에 수 십 GB의 용량이 보편적인 현재, FEOL, BEOL 기술을 모두 가지고 있는 국내의 반도체 소자 업체들은 자연스럽게 TSV 기술과 이에 필요한 장비의 개발에 관심을 가지게 되었다. 특히 이 중 TSV용 스퍼터링 장치는 transistor의 main contact 공정에 전 세계 시장의 90% 이상을 점유하고 있는 글로벌 업체의 경우에도 완전히 만족스러운 장비를 공급하지는 못하고 있는 상태여서 연구 개발의 적절한 시기이다. 기본 개념은 일반적인 마그네트론 스퍼터링이 중성 입자를 타겟 표면에서 발생시키는데 이를 다시 추가적인 전력 공급으로 전자 - 중성 충돌로 인한 이온화 과정을 추가하고 여기서 발생된 타겟 이온들을 웨이퍼의 표면에 최대한 수직 방향으로 입사시키려는 노력이 핵심이다. 본 발표에서는 고전력 이온화 스퍼터링 시스템의 자기장 해석, 냉각 효율 해석, 멀티 모듈 회전 자석 음극에 대한 동역학적 분석 결과를 발표한다. 그림1에는 이중 회전 모듈에 대한 다물체 동역학 해석을 Adams s/w package로 해석하기 위하여 작성한 모델이고 그림2는 180도 회전한 서브 모듈의 위상이 음극 냉각에 미치는 효과를 CFD-ACE+로 유동 해석한 결과를 나타내고 있다.