• 한국정밀공학회지
• /
• 제27권5호
• /
• pp.56-62
• /
• 2010

This paper presents the development process of roof carrier assembly using a one side release system for a vehicle. An RV(Recreational Vehicle) or SUV(Sports Utility Vehicle) has a roof carrier system on an upper surface of a roof panel for loading large or long size baggage. Such a roof carrier system is comprised of a roof rack longitudinally mounted on a roof panel and cross bar perpendicularly installed in the horizontal direction. Several locking mechanisms used in most vehicle roof carrier systems are composed with both side releasable locking ones. The obvious drawback to this arrangement is that when the user desires to reposition the cross bar, first one of the locking members must be unlocked and then the user must walk around to the opposite side of the vehicle to unlock the other member. In this paper, we proposed a newly locking mechanism, which allows a user simultaneously place both locking members of the roof carrier in locked and unlocked positions. In order to estimate design compatibility, structural and modal analysis is performed. Furthermore, a prototype based on the proposed design has been made, and then durability test carried out. From the simulation and experimental results, the proposed roof carrier system is proved effective and safe.

• Journal of Electrical Engineering and Technology
• /
• 제6권1호
• /
• pp.67-75
• /
• 2011

The development of electric vehicle power electronics system control, composed of DC-AC inverters and DC-DC converters, attract much research interest in the modern industry. A DC-AC inverter supplies the high-power motor torques of the propulsion system and utility loads of electric vehicles, whereas a DC-DC converter supplies the conventional low-power and low-voltage loads. However, the need for high-power bidirectional DC-DC converters in future electric vehicles has led to the development of many new topologies of DC-DC converters. The nonlinear control of power converters is an active research area in the field of power electronics. This paper focuses on the use of the fuzzy sliding mode strategy as a control strategy for buck-boost DC-DC converter power supplies in electric vehicles. The proposed fuzzy controller specifies changes in control signals based on the surface and knowledge on surface changes to satisfy the sliding mode stability and attraction conditions. The performance of the proposed fuzzy sliding controller is compared to that of the classical sliding mode controller. The satisfactory simulation results show the efficiency of the proposed control law, which reduces the chattering phenomenon. Moreover, the obtained results prove the robustness of the proposed control law against variations in load resistance and input voltage in the studied converter.

• Journal of Advanced Marine Engineering and Technology
• /
• 제32권6호
• /
• pp.841-846
• /
• 2008

Recently the LNG(liquified natural gas) public buses have been introduced to prevent the air pollution in metropolitan areas. As the LNG temperature in fuel tank is as low as $-162^{\circ}C$. the thermal and structural effects of tank components need to be studied for safe introduction in the market. Especially the support system of LNG fuel tank in vehicle, which has connected with inside and outside of tanks, should put attention to reduce the structural stress due to cryogenic temperature and to restrict the heat flux from ambient. There are two supporting systems in the tank, that one is connected between inside and outside tanks by welding, and the other is the inserted support system which is a cylindrical SUS bar inserted in a hole of the supporting plate. In this study the temperature distribution and thermal stress of the inserted support system were evaluated by using the utility program as ANSYS. The results showed that the rate of heat transfer to inner tank through this support system was quite small due to limited contact of support bar with plate. but the thermal stress of support plate was obtained beyond the limited tensile value of SUS304. The cautious design for the support plate part, therefore, should be given to make the safe support system of LNG vehicle fuel tank.

• 산업경영시스템학회지
• /
• 제40권1호
• /
• pp.1-10
• /
• 2017

The difficulties in opening and closing a sport utility vehicle (SUV) tailgate is important aspect of JD (James David) power's Initial Quality Survey (IQS) assessment, and affective quality has a big impact on the the success of thesedays products. The purpose of this study is to evaluate the perceived difficulty and satisfaction of customers by the opening and closing of the tailgate and to grasp the relationship between them and the opening and closing reaction force. The mechanical force required to open and close 42 domestic and overseas SUV tailgates was measured with the help of an auto company. In the experiment, 100 male drivers in their 20s to 50s evaluated perceived difficulty and satisfaction with opening and closing the tailgate. The results of the analysis showed that perceived difficulty and satisfaction were statistically different depending on the vehicle, but did not depend on the personal characteristics of the participants. The perceived difficulty and satisfaction regression model of tailgate opening and closing was developed by mechanical force variables and had a relatively high adjusted $R^2$ ranging from 0.62 to 0.73. The models showed that the the initial close and open force, the difference between initial and maximum close force and the difference between initial and auto-fall angle should be small for the low perceived exertion and high satisfaction. In addition, the correlation analysis between IQS score of tailages and perceived difficulty and satisfaction showed that the IQS scores were more related to the perceived difficulty and satisfaction of closing than those of opening. The results of the study will be helpful to design and test mechanical open and close structure of SUV tailgates.

• 자원ㆍ환경경제연구
• /
• 제23권2호
• /
• pp.281-304
• /
• 2014

친환경 자동차의 보급을 활성화시키기 위해서는 자동차 소비자들을 분석하는 것이 필수적이다. 본 연구는 자동차 소비자들의 특성과 친환경 자동차 선호의 관계를 성별 연령 연료비 중심으로 분석하였다. 설문조사를 이용한 컨조인트법을 이용하여 응답자를 성별 연령 연료비의 기준으로 구분하여 친환경 자동차의 속성이 효용에 미치는 영향을 분석한 결과, 응답자의 특성에 따라 자동차의 속성에 대한 한계효용에 유의한 차이가 있는 것을 발견할 수 있었다. 또한 자동차의 속성이 응답자의 효용수준에 미치는 영향이 같을 지라도 보상변이로 표출될 때는 다르게 나타날 수 있고, 반대로 효용수준에 미치는 영향이 다를지라도 보상변이는 같은 수준으로 나타날 수 있다는 것을 알 수 있었다. 한계효용은 주관적인 기준이기 때문에 응답자마다 다를 수 있는 반면, 보상변이는 상충관계를 이용한 객관적인 기준이 될 수 있기 때문에 응답자 특성에 따른 실질적인 선호의 차이를 나타낼 수 있다. 보상변이에 의하면 남성과 장년이 연비가 높은 차량을 더욱 선호하는 것으로 나타났다. 고유류비 소비자는 저유류비 소비자보다 주유시간에 더욱 민감하에 반응하고, 휘발유 차량은 청년층에서 더욱 선호된다.

• 전기학회논문지
• /
• 제60권3호
• /
• pp.566-571
• /
• 2011

As Plug-in Hybrid Vehicle and Electric Vehicle (PHEV/EV) take a greater share in the personal automobile market, their high penetration levels may bring potential challenges to electric utility especially at the distribution level. Thus, there is a need for the flexible charging management strategy to compromise the benefits of both PHEV/EV owners and power grid side. There are many different management methods that depend on the objective function and the constraints caused by the system. In this paper, the schema and dispatching schedule of centralized PHEV/EV charging spot network are analyzed. Also, we proposed and compared three power allocation strategies for centralized charging spot. The first strategy aims to maximize state of vehicles at plug-out time, the rest methods are equalized allocation and prioritized allocation based on vehicles SoC. The simulation results show that each run of the optimized algorithms can produce the satisfactory solutions to response properly the requirement from PHEV/EV customers.

• 대한교통학회지
• /
• 제27권3호
• /
• pp.39-47
• /
• 2009

교통안전시설 실무편람에 의하면 현재 U-Turn 설치 가능한 지점으로 최소폭원을 '편도 폭 9m 이상'의 지점으로 하고 있으며, U-Turn 허용차량은 승용차로 제한하는 것을 원칙으로 하도록 규정하고 있다. 그러나 최근 대형화된 승용차와 보편화된 SUV(sports utility vehicle)차량이 한번에 U-Turn을 완료하지 못하면서 교통소통과 교통안전에 문제를 야기시키고 있다. 본 연구에서는 실제 차량을 이용한 U-turn 회전반경의 실차 조사치와 교통사고 재현 프로그램인 PC-Crash에 의한 예측치를 비교 검정한 후 PC-Crash를 이용하여 국내 승용차에 대해 U-turn 회전반경에 대해서 예측하고 U-Turn 설치를 위한 적정 폭원으로 제시하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제16권8호
• /
• pp.2666-2687
• /
• 2022

As a new alternative communication scheme in 5G, unmanned aerial vehicle (UAV) is used as a relay in the remote base station (BS) for assistant communication. In order to ameliorate the quality of the backhaul link, a UAV backhaul transmission scheme based on improved Nash equilibrium (NE) strategy is proposed. First, the capacity of air-to-ground (A2G) channel by the link preprocess is maximized. Then, the maximum utility function of each UAV is used as the basis of obtaining NE point according to the backhaul channel and the backhaul congestion. Finally, the improved NE strategy is applied in multiple iterations until maximum utility functions of all the UAVs are reached, and the UAVs which are rejected by air-to-air (A2A) link during the process would participate in the source recovery process to construct a multi-hop backhaul network. Simulation results show that average effective backhaul rate, minimum effective backhaul rate increases by 10%, 28.5% respectively in ideal A2G channel, and 11.8%, 42.3% respectively in fading channel, comparing to pure NE strategy. And the average number of iterations is decreased by 5%.

• 대한기계학회논문집A
• /
• 제36권11호
• /
• pp.1421-1426
• /
• 2012

차량 선회 시 조종안정성과 주행 승차감을 향상시키기 위하여 능동적으로 차체의 롤(roll)을 줄이기 위한 연구가 진행되고 있다. 전동식 능동 롤 제어(ARC) 시스템은 전후 스테빌라이저바 중앙에 위치한 전동 모터 방식의 구동기에 의해 차량의 차체 롤을 제어한다. 본 연구에서는 이러한 전동식 ARC 시스템의 제어 성능 및 차량 동역학적 특성을 평가하고 검증하기 위한 해석, 벤치 시험, 실차 시험의 3단계 절차와 방법을 제안하였다. ARC 제어로직의 성능 및 타당성 평가를 위한 Matlab/Simulink와 CarSim 간의 연동-해석 방법을 제안하였고, ARC 구동기 및 시스템의 성능을 평가하기 위한 벤치 시험 방법과 실차 시험 방법을 제안하였다.

• 한국산학기술학회논문지
• /
• 제19권2호
• /
• pp.689-694
• /
• 2018

최근 친환경 자동차 개발과 함께 대기 오염 문제 대응을 위해서 자동차 연비 개선은 차량 개발에 있어서 매우 중요하다. 개발 차량의 연비 향상을 위한 요소 중 차량 외관을 타고 흐르는 공기 흐름과 차량 후부에서의 공기 유동 현상은 중요한 요소이다. 특별히 SUV(Sports Utility Vehicle) 차량의 차량 후부 공기 유동은 리어 스포일러 설계 시 고려해야 하는 중요한 설계 항목 중 하나이다. 본 연구에서는 차량의 공기 유동에 영향을 주는 리어 스포일러의 제어 인자를 정하고 각 제어 인자의 공기 유동 특성에 대한 민감도를 시험을 통하여 비교 분석하고, 유동 저항력을 감소시킬 수 있는 스포일러의 최적 제어 인자를 결정하였다. 결정된 최적 제어 인자를 이용한 시험 모델을 만들어 시험평가하고 그 결과 값에 대한 S/N비와 평균값을 분석하여 제어 인자 값을 변경하였다. 변경된 최적 제어 인자 값을 이용한 개선 모델을 다시 제작하고 유동 시험을 실시하여 공기 저항력 감소 효과와 원가절감 효과를 확인하였다.