• 대한기계학회논문집A
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• 제29권7호
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• pp.1005-1012
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• 2005

An OHT(Over Head Transportation) vehicle is an example of the industrial monorail vehicle, and it is used in the automobile, semiconductor, LCD manufacturing industries. OHT vehicle is moved by main wheels and guide rollers. The major function of the main wheel is to support and drive the OHT vehicle. The roles of the guide roller is the inhibition of derailment and steering of the OHT vehicle. Since the required vehicle velocity becomes faster and the required load capacity is increased, the durability characteristics of the wheel and roller, which was made of urethane, need to be increased. So it is necessary to estimate the fatigue life cycle of the wheel and roller. In this study, OHT dynamic model was developed by using the multi body dynamic analysis program ADAMS. Wheel and roller are modeled by the 3-D surface contact module. Especially, motor cycle tire mechanics is used in the wheel contact model. The OHT dynamic model can analyze the dynamic characteristic of the OHT vehicle with various driving conditions. And the result was verified by a vehicle traveling test. As a result of this study, the developed model is expected to predict wheel dynamic load time history and makes a contribution to design of a new monorail vehicle.

• 대한기계학회논문집A
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• 제33권5호
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• pp.521-528
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• 2009

One of reliability measurements of vehicle is estimated by driving mileage but the reliability of component, such as an hydraulic clutch system, is defined from the number of successful operational cycle. Relationship between these reliability measurement variables(mileage and cycle) should be examined first of all in the reliability estimation of components. Relationship between mileage and cycles is commonly known as linear function. However, the gradient depends on the operational environmental condition. Therefore, estimation of mission profile variable should be done with correlation analysis at the same time. In this paper, we derive mission profile variable of an hydraulic clutch system by field vehicle test and suggest the determination process of durability test parameters of CMC(Clutch Master Cylinder) with mission profile variable.

• 한국수소및신에너지학회논문집
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• 제29권3호
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• pp.299-305
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• 2018

The domestic label fuel economy measurement method is the same as the North American measurement method. The results of two test modes (city [FTP-75 mode], highway [HWFET mode]) are calculated to be equivalent to the final fuel economy value calculated as the result of five test modes reflecting various environmental conditions and driving patterns 5-cycle correction formula is used. In this study, we tried to find out that the difference between the domestic label fuel economy of the vehicle and the real road fuel economy felt by the driver compared to the new vehicle condition as the mileage increases. Using domestic label fuel economy measurement method, Four gasoline vehicles and four diesel vehicles were tested for the fuel economy of a new vehicle with a mileage of 150 km or less and domestic fuel economy test $6,500{\pm}1,000km$ durability condition and 15,000 km durability. It is confirmed that the certain portion (6,500 km endurance vehicle) The increase in mileage did not affect the fuel economy or the emission gas significantly, indicating that vehicle durability was limited.

• 한국산학기술학회논문지
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• 제12권4호
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• pp.1495-1501
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• 2011

본 연구는 동력전달 장치인 추진축이 차량 주행중 상하운동에 따라 생기는 자재이음의 내구성에 대한 강도 해석을 하였다. 유니버설 조인트에서의 최대 등가 응력과 전변형량은 요크 부분에서 $1.3177{\times}10^3$Pa및 $3.6148{\times}10^{-4}$m로 크게 나타났다. 'SAE bracket', 'SAE transmission' 및 Sample history'의 불규칙 피로 하중들 중에서는 하중의 변화가 극심한 SAE bracket'의 경우가 사용 가능 수명이 15951 Cycle 정도로 가장 짧은 것을 볼 수가 있고 하중의 변화가 가장 완만한 Sample history'에서 사용가능 수명이 $2{\times}10^7$ Cycle 정도로 가장 긴 것을 알 수 있었다. 피로 하중의 빈도수로서는 SAE Bracket history'가 80% 정도로서 가장 높게 나타나 파손의 가능성이 큼을 알 수 있었고 Sample history'가 5%로서 가장 낮게 나타났다. 그리고 구속 조건을 가하여 한 Harmonic response 해석에서의 최대 변위는 58Hz에서 일어났다. 이러한 진동수에서의 최대 변위는 0.00261m가 되었다. 본 연구의 결과를 종합하여 동력전달 장치인 추진축에 응용한다면 그 파손 방지 및 내구성을 예측하는데 활용이 클 것으로 사료된다.

• 한국산학기술학회논문지
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• 제21권11호
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• pp.851-860
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• 2020

인구 고령화와 건강 복지에 대한 사회적 관심이 높아지면서 재활복지기를 포함한 실버 및 헬스케어 산업과 관련한 연구들이 활발하게 진행되고 있다. 본 연구에서는 기존에 1차적으로 설계·제작되었던 이·승강 전동휠체어를 사용자 측면에서 보다 더 안전성과 편의성을 갖도록 개선하고자 하였다. 사용자 체형을 고려한 헤드레스트 높이조절 기능의 시트 디자인, 사용성 증대를 위한 암레스트의 길이조절 및 95° 회전 기능, 사용자 탑승 편의성을 위한 바닥까지의 시트하강 및 운행 시 승강할 수 있는 기능, 캐스터 회전반경 및 안전성 증대를 위한 발판 추가 및 풋레스트 길이 조절 기능, 승·하강 시 흔들림 방지를 위한 프레임 및 승·하강 링크 설계 등을 개선시켰다. 또한 안전주행을 위한 컨트롤러 및 드라이브 부문과 사용자 편의성 측면의 기능들을 추가적으로 설계·제작하였다. 추가 기능을 보완하여 제작된 실내 전동휠체어의 동작 상태를 평가하기 위해 구동 실험을 수행하였다. 연속 주행시간, 회전반경, 승·하강 최대 하중, 최대 승강 높이, 소음레벨, 운행 보조센서 센싱 최소거리, 서버 및 앱 프로그램 상호연동 및 기기호환성, 듀티 사이클 최대 오차율의 성능실험을 수행하였다. 실험 결과, 더 개선하여 설계·제작한 전동휠체어는 시험 목표 값을 달성하였으며, 성공적으로 동작하는 것을 확인할 수 있었다. 향후 연구로는 개선하여 제작된 이·승강 전동휠체어에 대해 사용자 측면에서의 사용성 평가를 수행할 것이다.

• 에너지공학
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• 제17권4호
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• pp.227-232
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• 2008

이산화탄소는 지구온난화를 일으키는 온실가스의 하나의 주요요인으로 생각되어진다. $CO_2$는 탄화수소를 연료로 사용하는 연소에서 배기가스의 주성분이다. 자동차의 $CO_2$ 배출물에 대한 규제는 최근에 더욱 절박하게 대두되어 왔다. 이러한 심각한 규제는 배기가스를 저감하는 대체연료를 개발할 수 있는 자동차 제품들에게 요구되는 것이다. 본 논문은 가솔린, 디젤, LPG 자동차를 사용하여, FTP-75와 NEDC(ECE15+EUDC) 모두에 따라서 $CO_2$ 배출물과 연료소비율(연비)과의 상관관계를 검토했다. 이 논문을 통해서 탄소중량비가 낮은 연료 일수록 $CO_2$ 발생량의 감소율이 큰 것을 알 수 있다. 사용한 연료에 따라서 $CO_2$ 배출량과 연비와의 관계를 함수로 표현할 수 있었으며, 높은 상관관계를 갖는 것을 알 수 있었다. LPG차량은 휘발유와 디젤차량보다 $CO_2$ 배출량이 적게 배출되는 것을 알 수 있었다.

• 한국자동차공학회논문집
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• 제13권3호
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• pp.1-9
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• 2005

In this paper, an operation algorithm and a performance simulator are developed for a 42-volt ISG vehiclewhich consists of 5 kW ISG, 2500cc IC engine, torque converter and 4 speed automatic transmission. Modularapproach using MATLAB Simulink is used to construct a dynamic model of the vehicle powertrain which is obtainedfrom each component such as engine, battery, ISG, torque converter, etc.. An operation strategy for a 42-volt ISG vehicle including the function such as engine idle stop and regenerative braking is proposed. Performance simulator is developed based on the dynamic models of the powertrain. It is found from the simulation results that fuel economy can be improved as much as 6 percent for FTP75 driving cycle mostly owing to the engine idle stop.

• Molecules and Cells
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• 제43권11호
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• pp.899-908
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• 2020

Intrinsically disordered proteins or regions (IDPs or IDRs) are widespread in the eukaryotic proteome. Although lacking stable three-dimensional structures in the free forms, IDRs perform critical functions in various cellular processes. Accordingly, mutations and altered expression of IDRs are associated with many pathological conditions. Hence, it is of great importance to understand at the molecular level how IDRs interact with their binding partners. In particular, discovering the unique interaction features of IDRs originating from their dynamic nature may reveal uncharted regulatory mechanisms of specific biological processes. Here we discuss the mechanisms of the macromolecular interactions mediated by IDRs and present the relevant cellular processes including transcription, cell cycle progression, signaling, and nucleocytoplasmic transport. Of special interest is the multivalent binding nature of IDRs driving assembly of multicomponent macromolecular complexes. Integrating the previous theoretical and experimental investigations, we suggest that such IDR-driven multiprotein complexes can function as versatile allosteric switches to process diverse cellular signals. Finally, we discuss the future challenges and potential medical applications of the IDR research.

• Journal of Power Electronics
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• 제17권2호
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• pp.398-410
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• 2017

This work presents the design of a dual extended Kalman filter (EKF) as a state/parameter estimator suitable for adaptive state-of-charge (SoC) estimation of an automotive lithium-iron-phosphate ($LiFePO_4$) cell. The design of both estimators is based on an experimentally identified, lumped-parameter equivalent battery electrical circuit model. In the proposed estimation scheme, the parameter estimator has been used to adapt the SoC EKF-based estimator, which may be sensitive to nonlinear map errors of battery parameters. A suitable weighting scheme has also been proposed to achieve a smooth transition between the parameter estimator-based adaptation and internal model within the SoC estimator. The effectiveness of the proposed SoC and parameter estimators, as well as the combined dual estimator, has been verified through computer simulations on the developed battery model subject to New European Driving Cycle (NEDC) related operating regimes.

• 한국분무공학회지
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• 제23권3호
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• pp.136-148
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• 2018

Major countries have tighten their NOx regulation of diesel passenger cars. In the case of the EU, the regulation has been toughen up to 6.25 times since 2000. Despite the regulation the NOx concentration of the ambient has not been reduced proportionally. As these issues, to reduce NOx emission practically, Korea and the EU introduced the real-world driving emission (RDE) regulation and the test method that will be applied after 2017. In this paper, for the regulation to make a soft landing in Korea, 6 diesel passenger cars which met Euro 6a~6d regulation and were equipped with LNT/SCR were tested at a chassis dynamometer with environmental chamber applying the off-cycles (FTP, US06, SC03, HWFET and CADC) and several ambient conditions (-7 and $14^{\circ}C$) as well as certification modes (NEDC, WLTC@ $23^{\circ}C$). The result of the test showed that the ambient temp. and the engine load as a test mode impacted the NOx emission of the cars while the vehicles with SCR emitted NOx lower than with LNT. Additionally, to propose an effective RDE test method, the above result was compared with the results of the other papers which tested RDE using the same cars.