영상기반 차량인식 기법을 이용한 교통류 추정에 관한 연구

김민정,정대한,김회경 한국ITS학회 2019 한국ITS학회논문지 Vol.18 No.6

Traffic data is the most basic element necessary for transportation planning and traffic system operation. Recently, a method of estimating traffic flow characteristics using distance to a leading vehicle measured by an ADAS camera has been attempted. This study investigated the feasibility of the ADAS vehicle reflecting the distance error of image-based vehicle identification technology as a means to estimate the traffic flow through the normalized root mean square error (NRMSE) based on the number of lanes, traffic demand, penetration rate of probe vehicle, and time-space estimation area by employing the microscopic simulation model, VISSIM. As a result, the estimate of low density traffic flow (i.e., LOS A, LOS B) is unreliable due to the limitation of the maximum identification distance of ADAS camera. Although the reliability of the estimates can be improved if multiple lanes, high traffic demands, and high penetration rates are implemented, artificially raising the penetration rates is unrealistic. Their reliability can be improved by extending the time dimension of the estimation area as well, but the most influential one is the driving behavior of the ADAS vehicle. In conclusion, although it is not possible to accurately estimate the traffic flow with the ADAS camera, its applicability will be expanded by improving its performance and functions. 교통 데이터는 교통계획이나 교통시스템 운영에 필요한 기초 자료이며 최근 ADAS 카메라로측정한 선행 차량과의 거리를 이용하여 교통류를 파악하는 방법이 시도되고 있다. 본 연구는 영상기반 차량인식의 거리오차를 반영한 미시적 시뮬레이션 분석을 통해 교통류를 추정하기 위한ADAS 차량의 활용 가능성을 살펴보았다. 차로수, 교통수요, 프로브 차량의 점유율(MPR), 시공간검지영역 등에 따른 교통류 추정치의 표준 평균 제곱근 오차를 통해 분석을 수행하였다. 분석결과, ADAS 카메라의 최대 인식거리의 한계로 저밀도 교통류(LOS A, LOS B)의 추정치는 신뢰할 수 없는 수준이다. 다차로나 교통수요가 크고 점유율(MPR)이 높을 경우 추정치의 신뢰성이개선될 수 있지만, 인위적으로 점유율(MPR)을 높이는 것은 현실적으로 어려움이 있다. 또한, 검지영역의 시간범위를 연장함으로써 추정치의 신뢰성을 개선할 수 있지만, 가장 크게 영향을 미치는 것은 ADAS 차량의 주행행태로서 해당 차량이 도로의 교통류와 상이한 주행행태를 보일경우 그 추정치는 신뢰할 수 없게 된다. 결론적으로 모든 교통류를 정확히 추정하지는 못 하지만ADAS 카메라의 성능이나 기능을 개선함으로써 ADAS 차량의 활용 가능성은 확대될 것이다.

차량-인프라 연계(Ⅶ) 기반 교통정보시스템의 RSE 설치간격 결정 방법론 (연속류를 중심으로)

박준형,오철,임희섭,강경표 대한교통학회 2009 대한교통학회지 Vol.27 No.6

A variety of research efforts, using advanced wireless communication technologies, have been made to develop more reliable traffic information system. This study presents a novel decentralized traffic information system based on vehicle infrastructure integration (Ⅶ). A major objective of this study was also to devise a methodology for determining appropriate spacing of roadside equipment (RSE) to fully exploit the benefits of the proposed VII-based traffic information system. Evaluation of travel time estimation accuracy was conducted with various RSE spacings and the market penetration rates of equipped vehicle. A microscopic traffic simulator, VISSIM, was used to obtain individual vehicle travel information for the evaluation. In addition, the ANOVA tests were conducted to draw statistically significant results of simulation analyses in determining the RSE spacing. It is expected that the proposed methodology will be a valuable precursor to implementing capability-enhanced next generation traffic information systems under the forthcoming ubiquitous transportation environment. 실시간 교통자료 수집 기술의 혁신을 위해 유비퀴터스 환경기반의 교통정보시스템을 구성하는 인프라(RSE)의 적정 설치간격을 설정하는 방법론을 연구하였다. 적정설치간격을 도출하기 위해 연속류 교통상황 모니터링에 효과적으로 사용될 수 있는 구간통행시간을 평가척도로 설정하고, 인프라(RSE)의 통신반경 내에 위치하는 개별차량의 주행자료에서 속도자료를 추출하여 구간통행시간을 산출하였다. 교통상황에 따른 생성정보의 정확도와 적정 설치간격을 분석하기 위해 정상교통류와 교통사고로 인한 혼잡교통류 상황을 설정하여 개별차량 주행궤적을 수집하였다. RSE 설치간격, MPR(Market Penetration Rate), Time window를 주요변수로 정의하고 산출된 구간통행시간의 정확도를 MAPE(Mean Absolute Percentage Error)를 이용하여 평가하였다. 인프라(RSE) 설치간격 값은 1km에서 0.5km씩 증가시키면서 2.5km까지 적용하였다. 구간통행시간의 평가결과 2.5km의 간격으로 인프라(RSE)를 설치할 때 생성된 구간정보의 정확도가 급격히 감소되었다. 분석결과의 통계적 유의성을 평가하기 위해 분산분석을 수행하였다. 적정수준의 정확도가 확보된 구간정보의 생성이 가능하면서 인프라(RSE)를 최대간격으로 설치하기 위한 RSE 적정간격 설치방법론을 제시하였다. 본 연구에서 제시한 RSE의 적정설치간격 도출 방법론은 향후 차세대 교통수집체계인 유비퀴터스 환경기반 교통정보시스템의 요구사항 수립을 위해 효과적으로 사용될 것으로 기대된다.

차량 안정성 및 선회 성능을 고려한 휠 모터 구동 버스 시스템 제어 알고리즘 개발

정종렬(Jongryeol Jeong),최종대(Jongdae Choi),신창우(Chang Woo Shin),임원식(Wonsik Lim),차석원(Suk Won Cha) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5

Recently, many academies and vehicle companies have researched electric vehicle able to be a solution of global warming and increasing of oil price. Wheel motor drive system which do not utilizes complex transmission or differential gear is an effective vehicle system of various kinds of electric vehicle system. In wheel motor drive system, appropriate power distribution of traction motors should be conducted for the performance of cornering and safety of the vehicle. In this paper, a control algorithm based on PID control theory was developed for the traction of the vehicle. With the developed control algorithm, forward simulations were conducted using six degrees of freedom vehicle dynamics simulation program. From the simulation results, it was verified of safety and cornering performance of the vehicle. For the actual application of the control algorithm, further research, such as combining with regenerative braking algorithm or vehicle speed estimation algorithm, is on the plan.

100kW급 연료전지 열관리 시스템 실도로 운전조건 해석적 연구

이호성(Ho-Seong Lee),이무연(Moo-Yeon Lee),조중원(Choong-Won Cho) 한국산학기술학회 2019 한국산학기술학회논문지 Vol.20 No.2

본 연구의 목적은 100kW급 연료전지 시스템의 열관리 성능을 실도로 운전조건에서 분석하여, 성능 해석 모델링을 개발하는 것이다. 개발된 모델을 적용하여, 열관리 시스템의 운전조건 변화에 따른 성능 변화를 고찰하고자 한다. 해석 모델링은 핵심부품들에 대한 성능 평가 데이터를 바탕으로, 성능에 영향을 주는 변수들로 개발하였다. 개발된 연료전지 열관리 시스템 해석 모델링으로 다양한 실차 운전조건에서의 최적 열관리 시스템에 대한 전력소비량을 분석하였다. 주요하게, 연료전지 열관리시스템 핵심부품(워터펌프, 냉각 팬, 3 Way Valve, 라디에이터)에 대한 성능 특성 분석 후 모델링을 진행하였다. 개발된 모델링으로 운전조건에 따른 유량 예측을 하였고, 실험값과 예측값과의 비교분석을 통하여서, 해석 모델링에 대한 검증을 진행하였다. 과도해석을 통하여서, 냉시동시 냉각수 온도가 특정온도까지의 소요시간을 예측하였다. 스택 운전조건에서 스택 입출구 온도가 적정 수준에서 움직이기 위한 열관리 시스템 운전조건에 대한 예측을 진행하였다. 그 결과를 바탕으로, 소모전력과 열방출량과의 비교분석을 하였다. 개발된 해석 모델링은 핵심부품들의 성능 변화시 연료전지 시스템 운전에 대한 영향도를 분석할 수 있도록 활용할 예정이다. The objective of this study was to investigate performance characteristics of thermal management system(TMS) in a fuel cell electric vehicle with 100kW Fuel Cell(FC) system. In order to build up analytic modeling for TMS, each component was installed and tested under various operating conditions, such as water pump, radiator, 3-Way valve, COD heater, and FC stack etc. and as the results of them, correlations reflecting component’s characteristics with flow rate, air velocity were developed. Developed analytic modelling was carried out under various operating conditions on the road. To verify modelling’s accuracy, after prediction for optimum coolant flow rate was fulfilled under certain operating conditions, such as FC system, water pump speed, opening of 3-way valve, and pipe resistance, analytic and experimental values were compared and good agreement was shown. In order to predict cold-start operating performance for analytic modelling, coolant temperature variation was analyzed with –20℃ ambient temperature and duration was predicted to rise in optimum temperature for FC. Because there is appropriate temperature difference between inlet and outlet of FC stack to operate FC system properly, related analysis was performed with respect to power consumption for TMS and heat rejection rate and performance map was depicted along with FC operating conditions.

C-ITS 환경에서 차량 간 상호작용 분석을 통한 차내 경고 정보의 교통 안전성 효과 평가

고지은,장지용,오철 대한교통학회 2021 대한교통학회지 Vol.39 No.1

The cooperative-intelligent transport systems (C-ITS) shares useful real-time traffic information including upcoming hazards in support of vehicle-to-vehicle (V2V) and vehicle-to- infrastructure (V2I) wireless communications. The safety applications provided in the C-ITS environment allow the driver to respond quickly to unexpected hazardous situations and to prevent accidents. This study aims to quantitatively evaluate the safety benefits of C-ITS when the in-vehicle warning information is provided. A novel feature of this study is to use a multi-agent driving simulation method capable of analyzing vehicle interactions between a subject vehicle and a preceding vehicle in terms of crash risks. The crash potential index (CPI) is adopted to evaluate rear-end crash risks, and various compliance levels of C-ITS drivers are further taken into consideration in the analysis. In case the subject vehicle received the warning information was defined as the “With” scenario, and the case that the subject vehicle did not receive the warning information was defined as the “Without” scenario. In addition, to analyze the impact of providing alert information on traffic safety from compliance rates, it is defined in this study that drivers comply with given warning information in the case where the speed and CPI decrease after the warning message is displayed. And the changes in the probability of accidents caused by the subject’s compliance rate were compared. Results showed that the driving speeds and CPIs of the “With” scenarios were lower compared to the “Without” scenario, and 55.81% of CPI reduction was achievable due to the warning information provision. According to the CPI effectiveness analysis on the compliance rate, the average CPI decreased as the compliance rate increased. When all the drivers complied with the warning information in the C-ITS environment, the crash potential was reduced by 67.86% compared to the case that all drivers did not comply with the warning information. The outcomes of this study are expected to be useful as a fundamental for developing effective policies to fully exploit the benefits of C-ITS applications. Cooperative-Intelligent Transport Systems(C-ITS)은 차량과 차량, 차량과 인프라 간의 V2X 통신을 기반으로 전방의 위험 상황 정보를 운전자에게 실시간으로 제공한다. C-ITS 환경에서 제공되는 전방 위험상황 정보를 통해 운전자는 예기치 않은 위험 요소를 사전에 인지하고 신속하게 대응하여 사고를 예방하는 것이 가능하다. 본 연구의 목적은 C-ITS 환경에서 차량 내 경고 정보 제공에 대한 효과를 교통안전 측면에서 정량적으로 평가하는 것이다. 본 연구에서는 Multi-agent 주행시뮬레이터를 이용하여 주체 차량과 선행 차량 간의 상호 작용을 분석하였다는 점에서 기존연구와 차별성을 갖는다. 사고 발생 개연성을 정량적으로 평가하기 위한 평가지표로 주행 속도와 후미추돌 사고위험도를 나타내는 Crash Potential Index(CPI)를 사용하였다. 실험 시나리오는 주체차량에 경고 정보를 제공한 “With”시나리오와 경고 정보를 제공하지 않은 “Without”시나리오로 설정하였다. 또한 순응률에 따른 경고 정보 제공이 교통안전성에 미치는 영향을 분석하기 위해 경고 정보 제공 시 피실험자의 속도 및 CPI가 감소한 경우를 순응으로 정의하고, 피실험자의 순응률에 따른 사고 발생 개연성 변화를 비교하였다. 분석 결과, 경고 정보를 제공한 경우의 주행 속도 및 CPI가 경고 정보를 제공하지 않은 경우에 비해 감소하였으며 경고 정보를 제공 시 약 55.81%의 사고 발생 개연성 감소 효과가 있는 것으로 나타났다. 또한 순응률이 증가함에 따라 평균 CPI는 감소하며, 순응률이 100%인 경우가 순응률 0%인 경우에 비해 사고 발생 개연성이 약 67.86% 감소하는 것으로 나타났다. 즉 C-ITS 환경에서의 경고 정보 제공은 사고 발생 개연성을 감소시키고, 운전자의 순응률이 증가할수록 사고 발생 개연성 감소 효과가 증가하는 것으로 판단된다. 본 연구의 결과는 C-ITS 환경에서 순응률 향상을 통한 교통안전 개선 효과를 제고하기 위해 차량 내 경고 정보 서비스의 개발 및 운영관리 방안 수립 시 기초자료로 활용될 수 있을 것으로 기대된다.

Development of GNSS/WSS/YRS integration algorithm for land vehicle positioning

한중희,권재현,홍창기,이용 대한공간정보학회 2017 Spatial Information Research Vol.25 No.2

Since the Global Navigation Satellite System (GNSS) positioning technique provides precise navigation solutions for a long time, it has been broadly applied for the automotive navigation system. However, the inherent weakness of the GNSS technique is their reliance on the GNSS signal reception environment. To solve this problem, it is necessary to integrate dead reckoning sensors with GNSS positioning technique. Recently, the vehicle dynamic sensors are mounted on the passenger car to improve safety and convenience in driving. Among various vehicle dynamic sensors, wheel speed sensor (WSS) and yaw rate sensor (YRS) can measure the vehicle motion to operate dead reckoning system. In this study, GNSS/WSS/YRS integration algorithm for land vehicle positioning system is developed based on the loosely coupled integration using extended Kalman filter. The performance of the integration algorithm is evaluated based on two test data sets obtained by real test driving by simulating GNSS signal outage. It is found that the proposed algorithm estimates the horizontal positions with meter-level of accuracy when GNSS outage occurs for 30 s. However, the accuracy would be degraded due to irregular road surface so that the study to find additional constraints or integrate with other sensors is necessary in further study.

VEHICLE LONGITUDINAL AND LATERAL STABILITY ENHANCEMENT USING A TCS AND YAW MOTION CONTROLLER

J.-H. SONG,H.-S. KIM,B.-S. KIM 한국자동차공학회 2007 International journal of automotive technology Vol.8 No.1

This paper proposes a traction control system (TCS) that uses a sliding mode wheel slip controller and a PID throttle valve controller. In addition, a yaw motion controller (YMC) is also developed to improve lateral stability using a PID rear wheel steering angle controller. The dynamics of a vehicle and characteristics of the controllers are validated using a proposed full-car model. A driver model is also designed to steer the vehicle during maneuvers on a split μ road and double lane change maneuver. The simulation results show that the proposed full-car model is sufficient to predict vehicle responses accurately. The developed TCS provides improved acceleration performances on uniform slippery roads and split μ roads. When the vehicle is cornering and accelerating with the brake or engine TCS, understeer occurs. An integrated TCS eliminates these problems. The YMC with the integrated TCS improved the lateral stability and controllability of the vehicle.

VEHICLE LONGITUDINAL AND LATERAL STABILITY ENHANCEMENT USING A TCS AND YAW MOTION CONTROLLER

Song, J.H.,Kim, H.S.,Kim, B.S. The Korean Society of Automotive Engineers 2007 International journal of automotive technology Vol.8 No.1

This paper proposes a traction control system (TCS) that uses a sliding mode wheel slip controller and a PID throttle valve controller. In addition, a yaw motion controller (YMC) is also developed to improve lateral stability using a PID rear wheel steering angle controller. The dynamics of a vehicle and characteristics of the controllers are validated using a proposed full-car model. A driver model is also designed to steer the vehicle during maneuvers on a split ${\mu}$ road and double lane change maneuver. The simulation results show that the proposed full-car model is sufficient to predict vehicle responses accurately. The developed TCS provides improved acceleration performances on uniform slippery roads and split ${\mu}$ roads. When the vehicle is cornering and accelerating with the brake or engine TCS, understeer occurs. An integrated TCS eliminates these problems. The YMC with the integrated TCS improved the lateral stability and controllability of the vehicle.

A Study on Voltage Sag Considering Real-Time Traffic Volume of Electric Vehicles in South Korea

Go, Hyo-Sang,Kim, Doo-Ung,Kim, Jun-Hyeok,Lee, Soon-Jeong,Kim, Seul-Ki,Kim, Eung-Sang,Kim, Chul-Hwan The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

This paper analyzes the effect of voltage sag on distribution systems due to the connection of Electric Vehicles (EVs). In order to study the impact of the voltage sag on the power system, two scenarios have been selected in this paper. The distribution system and EVs are modeled using the Electro Magnetic Transients Program (EMTP). The numbers of EVs are predicted based on the number of vehicles in distribution system of Seoul. In addition, the number of EVs is set up using real-time traffic in Seoul to simulate Scenario I and II. The simulation results show that voltage sag can occur if the distribution system has more than 30% of the total number of vehicles.

A Study on Voltage Sag Considering Real-Time Traffic Volume of Electric Vehicles in South Korea

고효상,김두웅,김준혁,이순정,김슬기,김응상,김철환 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

This paper analyzes the effect of voltage sag on distribution systems due to the connection of Electric Vehicles (EVs). In order to study the impact of the voltage sag on the power system, two scenarios have been selected in this paper. The distribution system and EVs are modeled using the Electro Magnetic Transients Program (EMTP). The numbers of EVs are predicted based on the number of vehicles in distribution system of Seoul. In addition, the number of EVs is set up using realtime traffic in Seoul to simulate Scenario I and II. The simulation results show that voltage sag can occur if the distribution system has more than 30% of the total number of vehicles.