• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.12
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• pp.953-960
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• 2020

This paper presents an optimization of gear web design used in a main gear train of an engine reduction gearbox for a rotorcraft. The optimization involves the minimization of a total weight, transmission error, misalignment, and face load distribution factor. In particular, three design variables such as a gear web thickness, location of rim-web connection, and location of shaft-web connection were set as design parameters. In the optimization process, web, rim and shaft of gears were converted from the 3D CAD geometry model to the finite element model, and then provided as input to the gear simulation program, MASTA. Lastly, NSGA-II optimization method was used to find the best combination of design parameters. As a result of the optimization, the total weight, transmission error, misalignment, face load distribution factor were all reduced, and the maximum stress was also shown to be a safe level, confirming that the overall gear performance was improved.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2004.05a
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• pp.268-271
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• 2004

반도체 가공공정에서 웨이퍼의 정렬이나 각종 초정밀 가공에서 가공물의 각도를 미체 조정하기 위한 초정밀 메커니즘을 제안하였다. 일반적으로 각도를 결정하는 메커니즘은 기어를 이용한다. 기어를 이용할 경우 회전 분해능을 높일 수 있으나 기어의 백래쉬에 의한 오차가 있어 보다 높은 정밀도를 구현하기가 어렵다. 본 논문에서는 직접구동(direct drive) 방식과 이중서보(dual servo) 방식을 이용하여 기어를 사용하지 않고 회전 스테이지를 구현하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.31-36
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• 2002

Even through the problem of misalignment is of great importance, not much work has been reported in the literature on the effect of misalignment on the vibrations of the gear-bearing systems. Therefore, the nonlinear dynamic characteristics of the gear drive system due to misalignment are investigated in this work. Transmission error for helical gear and bearing nonlinear stiffness is calculated. The equation of motion of the gear drive system is modelled using the time-varying gear meshing stiffness, bearing nonlinear stiffness, and bearing pre-load due to the housing deformation. Numerical analysis lot the gear drive system show the result of misalignment effect - sub-harmonic component, bearing pre-load effect, and another nonlinear phenomenon. And the numerical analysis are verified by the experimental result.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.117-120
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• 2000

본 논문은 이동로봇이 주행 중 발생하는 heading 오차를 지자기센서를 이용하여 보정하고 주행을 정확히 제어하는 것에 관한 것이다. 일반적으로 이동로봇의 주행제어는 여러 원인에 의한 부정확성을 내포하고 있다. 예를 들어 바퀴의 부정확한 기계적 정렬, 기어의 헐거워짐, 센서 신호의 잡음과 오차, 바퀴의 미끄러짐, 평탄하지 않는 표면에 의한 제도변동 등이다. 따라서, 이동명령어 수행 시 이동로봇의 heading이 의도된 대로 유지되는지를 측정하는 오차 검출이 필요하며 이를 위한 센서 본 논문에서는 지자기센서를 이용하여 오차를 보정하였다. 실험은 무선 원격 제어되는 이동로봇에 지자기 센서를 부착하여 자계의 영향이 비교적 적은 평탄한 옥외에서 수행하였고, 실험 결과를 통해 지자기 센서를 이용한 이동로봇의 heading 오차 보정과 주행제어효과를 보여주었다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.5
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• pp.8-16
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• 2021

This study develops a shaft analysis model for the optimization of the power transmission system. The finite element method was used for the shaft analysis model. The shaft and gear were assumed Timoshenko beams. Strength was evaluated according to DIN 743, and gear misalignment was calculated through ISO 6336 and the coordinate system rotation. The analysis software for a power transmission system was developed using Visual Studio 2019. The analysis results of the developed program were compared with those of commercial software (MASTA, KISSsoft, and Romax). We confirmed that the force, deformation, and safety factors at each node were the same as those of the commercial software. The absolute value of the gear misalignment of the developed program and commercial software was different. However, the gear misalignment tended to increase with increasing the displacement in the tooth width direction.