고해상도 차량 주행 데이터의 수집 및 속도 정보 활용 방안

김상기 한국도로학회 2021 한국도로학회논문집 Vol.23 No.3

PURPOSES : This study introduces the use of instantaneous speed collected by in-vehicle sensing devices for space mean speed and time mean speed estimation. METHODS : Using probe vehicles’ instantaneous speed data and GPS location at each designated time interval enables analysts to calculate the link-based space mean speed and time mean speed for a certain time-space domain directly. This study proves the equations mathematically and compares the results of time mean speed using Wardrop’s equation and section average speed by trips. RESULTS : This study introduces the concept of link-based average speed using both time mean and space mean speed definitions. First, an unbiased space mean speed was explained for a roadway section can be calculated from high-resolution vehicle trajectory data without necessarily continuously tracking a vehicle. Second, this study proves that the average section speed by occupancy resulted in identical values to the true space mean speed formulation by Wardrop. In addition, the average section speed by trip was nearly identical to the time mean speed. CONCLUSIONS : Each section on a signalized intersection corridor yielded various speed distributions whose parameters varied as measurements were taken closer to the intersection proper. By exploring the space mean speed with speed distribution, the intersection impact area can be defined more accurately.

A model for investigating vehicle-bridge interaction under high moving speed

Hanyun Liu,Zhiwu Yu,Wei Guo,Yan Han 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.77 No.5

The speed of rail vehicles become higher and higher over two decades, and China has unveiled a prototype highspeed train in October 2020 that has been able to reach 400 km/h. At such high speeds, wheel-rail force items that had previously been ignored in common computational model should be reevaluated and reconsidered. Aiming at this problem, a new model for investigating the vehicle-bridge interaction at high moving speed is proposed. Comparing with the common model, the new model was more accurate and applicable, because it additionally considers the second-order pseudo-inertia forces effect and its modeling equilibrium position was based on the initial deformed curve of bridge, which could include the influences of temperature, pre-camber, shrinkage and creep deformation, and pier uneven settlement, etc. Taking 5 km/h as the speed interval, the dynamic responses of the classical vehicle-bridge system in the speed range of 5 km/h to 400 km/h are studied. The results show that ignoring the second-order pseudo-inertia force will underestimate the dynamic response of vehicle-bridge system and make the high-speed railway bridge structure design unsafe.

An Experimental Study on the Re-Useable Self-Locking Nut for High-Speed Rail Vehicle Bogie and Car Body Connection Device

이찬우(Chan Woo Lee) Korean Society for Precision Engineering 2017 한국정밀공학회지 Vol.34 No.12

The self-locking nuts that are used in high-speed railway-vehicle bogies and car-body connections are key components of the fastening system. These bogies and connection systems should withstand the high vibrations and shocks that are generated by high-speed operations. Since the first high-speed railway was developed, the antiloose nuts that are globally used in all of the high-speed rail-vehicle bogies and car-body connection systems are single-use limited to prevent nutloosening accidents during train operations. In this study, we developed a double reusable nut for the self-locking nuts of high-speed rail vehicles with a 100-% lifetime improvement. The proposed nut design was subjected to the KS R 9144 and NAS 3350 vibration-performance evaluation tests, and following the DIN 65151 method, a Junker test was performed for an impact-performance test. As the final step, a practical-application test was performed to assess the reusability of the proposed nut for which the self-locking nut of the HEMU-430X high-speed rail vehicle was utilized, and two reusability tests were subsequently carried out to evaluate the safety

Research on the Calculation of Rotor’s Convective Heat Transfer Coefficient of High-Speed Drive Motor for EVs Based on Multiple Scenarios

Wu Zhigang,Li Weili,Tang Haoyue,Luo Shifan,Zhang Liangliang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.6

In order to adapt the development demand of electric vehicle (EV) drive motor with high power density, high-speed motor is an inevitable trend. There have been numerous studies on the optimisation of cooling structures and losses in high-speed motor, but little has been said about the mechanism of heat transfer problems. Especially in the context of diverse driving scenarios and high-speed drive for EVs, it is crucial to study the differences in heat transfer mechanisms between high-speed motors and normal-speed motors. The research work is based on a principle prototype with a maximum speed of 50 kW-30,000 rpm. A dynamic calculation method is proposed for the rotor’s convective heat transfer coefficient (CHTC) over a wide speed range and multiple scenarios. This method has the advantages of simplicity and high efficiency in calculating the CHTC of rotor, and avoids the complex preprocessing and difficult convergence problems of the fluid–solid coupling calculation. Finally, the accuracy of the calculation results is verified by the temperature rise test of the high-speed motor.

고속철도 상 교량의 정밀 동적해석을 위한 개선된 수치적분법

오순택,심영우,이동준,윤준관 한국방재학회 2011 한국방재학회논문집 Vol.11 No.5

A dynamic analysis procedure is developed to provide a better estimation of the dynamic responses of bridge during the passage of high speed railway vehicles. Particularly, a three dimensional numerical model including the structural interaction between high speed vehicles, bridges and railway endures to analyse accurately and evaluate with in-depth parametric studies for dynamic responses of bridge running high speed railway vehicles. Three dimensional frame element is used to model the prestressed concrete box girder bridges. (40m simple types) Track irregularity employed as a stationary random process from the given spectral density functions and irregularities of both sides of the track are assumed to have high correlation. The high-speed railway vehicle (KTX) is used as 38-degree of freedom system. Three displacements (vertical, lateral, and longitudinal) as well as three rotational components (pitching, rolling, and yawing) are considered in the 38-degree of freedom model. The dynamic amplification factors are evaluated by the developed procedure under various traveling conditions, such as track irregularity camber, train speed and ballast. The dynamic analysis such as Newmark and Runge-Kutta methods which are able to analyse considering the dynamic impact factors are compared and contrasted. 고속철도상 교량의 동적응답을 보다 정밀하게 해석하기 위한 동적해석방법을 개발하였다. 고속으로 주행하는 동력차에 의한 교량의 동적거동을 면밀한 속도변수분석과 고속철, 교량 그리고 궤도구조물의 상호작용을 포함한 수치모델로 구성하였다. 40미터 단순지간의 PSC박스거더교를 3차원 유한 프레임요소로 모델링 하였다. 스펙트럼 밀도함수로 산출된 궤도불규칙값과 궤도간 상이한 거리차이를 고려하여 고속철 차량은(KTX) 38자유도로 구성하였다. 38자유도 모델은 3방향 변위와 상응하는 회전각을 고려하였다. 동적증폭계수는 다양한 궤도의 불규칙성, 켐버, 주행속도, 자갈도상과 같은 주행조건에 의해 결정된다. 이와 같은 동적증폭계수를 해석하기 위하여 Newmark-β 기법과 Runge-Kutta 기법을 적용하여 비교분석하였다.

QoS-aware Cross Layer Handover Scheme for High-Speed vehicles

( Heba Nashaat ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.1

High-Speed vehicles can be considered as multiple mobile nodes that move together in a large-scale mobile network. High-speed makes the time allowed for a mobile node to complete a handover procedure shorter and more frequently. Hence, several protocols are used to manage the mobility of mobile nodes such as Network Mobility (NEMO). However, there are still some problems such as high handover latency and packet loss. So efficient handover management is needed to meet Quality of Service (QoS) requirements for real-time applications. This paper utilizes the cross-layer seamless handover technique for network mobility presented in cellular networks. It extends this technique to propose QoS-aware NEMO protocol which considers QoS requirements for real-time applications. A novel analytical framework is developed to compare the performance of the proposed protocol with basic NEMO using cost functions for realistic city mobility model. The numerical results show that QoS-aware NEMO protocol improves the performance in terms of handover latency, packet delivery cost, location update cost, and total cost.

초고속 비행체를 위한 준 자유흐름식 고공환경 모사시험설비의 설계 및 상온실험

이성민,유이상,박진수,고영성,김선진,이정민 한국추진공학회 2018 한국추진공학회지 Vol.22 No.2

In this study, a cold flow test was carried out on a high-speed vehicle facility with a high-altitude environment simulator. Variable test was carried out according to the blockage ratio, angle, and length of the test model. It is confirmed that the blockage rate can be operated in the range of 40%, and that the model should be selected at an angle of 45 degrees or less. The variables of length are less dominant compared to the variables of blockage rate and angle. Through this, a database is obtained according to the parameters of the conical model of the high-speed vehicle test facility. 본 연구에서는 초고속 비행체 고공환경 모사실험 설비에 대한 설계와 상온실험을 진행하였다. 시험모델의 폐색율, 각도, 길이에 따른 변수실험을 진행하고, 변수에 따른 벽면압력변화를 확인하였다. 폐색율은 40%의 영역에서도 운용이 가능하며, 각도는 45도 이하의 크기에서 모델을 선정해야함을 확인하였다. 길이의 변수는 폐색율과 각도의 변수에 비하여 영향이 크지 않은 것을 확인하였다. 이를 통해서 초고속 비행체 시험설비에서 원뿔형 모델의 설계 변수에 따른 성능 데이터베이스를 확보하였다.

고속철도차량 제어카드 회로 개선을 통한 트리포드 고장 검지 신뢰성 향상에 관한 연구

오효석,박태용,최용은,김재문 대한전기학회 2023 전기학회논문지 Vol.72 No.10

High-speed railway vehicles require substantial power output to achieve high-speed operation, making the performance of the propulsion system, responsible for power supply, of utmost importance. The propulsion control system for high-speed railway vehicles varies in terms of output and control methods based on the vehicle type, but malfunctions can significantly disrupt railway operations. An analysis of recent three-year breakdown data from high-speed railways reveals issues such as short circuits, power supply failures, fan malfunctions, and converter overcurrent faults. Notably, control card replacements account for approximately 30% of all failures. However, control cards for propulsion control systems are not included in routine inspections, and their operational lifespan remains undefined, leading to the practice of replacement with spare parts upon failure. Furthermore, fault detection of control cards, resulting in erroneous fault identification, also impacts train operations. This paper confirms that the ESB3 card, responsible for detecting the unbalance of the tripod that transmits power among the control cards of the propulsion control system, detects an imbalance due to organic noise voltage generated during train operation. After improving the existing circuit, it was applied to a current vehicle test and verified as an improvement measure for fault detection.

궤도불규칙성에 의해 발생하는 복선고속철도교량의 충격응답에 관한 연구

송명관(Song Myung-Kwan) 대한토목학회 2007 대한토목학회논문집 A Vol.27 No.1A

본 연구에서는 교량-열차 상호작용을 고려한 고속철도교량의 3차원 유한요소 해석모델을 이용하여 고속열차가 복선궤도를 주행할 때 발생하는 고속철도교량의 충격응답에 관해 연구한다. 이 3차원 유한요소 해석모델에서는 고속철도교량의 각 구조 부재들을 모형화하기 위해서 개선된 다양한 유한요소들을 사용하였고, 특히,6자유도를 갖는 비적합 평면쉘 유한요소를 사용하여 박스형태의 교량상판을 모형화하였다. 이매개변수를 갖는 Winkler 탄성지반상의 보유한요소를 사용하되, 보절점 오프셋(offset) 개념을 적용하여 궤도구조물을 모형화하고, 관절형 대차시스템이 도입된 고속열차의 모형화를 위한 관절형 열차모형을 이용하였다 라그랑쥐 운동방정식을 이용하여 교량-열차 시스템의 운동방정식을 정식화하였다. 그리고, 교량-열차 상호 작용을 고려하여 교량 상에 작용하는 하중의 방정식을 유도함으로써, 교량-열차 전체 시스템의 완전한 시스템 행렬의 구성이 가능하다. 제안된 해석알고리즘을 이용하여 고속열차가 복선궤도를 주행할 때 궤도불규칙 정도에 따라 발생하는 고속철도교 량의 충격응답에 대해 고찰한다. In this study, the impact response of high-speed railway bridges due to trains on double tracks is investigated by using the 3-dimensional finite element analysis model of railway bridges considering high-speed train-bridge interaction. In the 3-dimensional finite element analysis model, the bridge deck of a railway bridge is modeled by the NFS (Nonconforming Flat Shell) elements with 6 degrees of freedom. And, track structures are idealized by using beam finite elements with the offset of beam nodes and those on two-parameter elastic foundation. The vehicle model devised for a high-speed train is employed, which has an articulated bogie system. By Lagrange's equations of motion, the equations of motion of the vehicle-bridge system can be formulated. In addition, by deriving the equations of the forces acting on the bridge considering the vehicle-bridge interaction forces, the complete system matrices of total vehicle-bridge system can be constructed. By using the proposed analysis algorithm, the impact response of high-speed railway bridges due to trains on double tracks as the degree of track irregularities is studied only through numerical analyses.

Dynamics of high-speed train in crosswinds based on an air-train-track interaction model

Wanming Zhai,Jizhong Yang,Zhen Li,Haiyan Han 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.20 No.2

A numerical model for analyzing airtraintrack interaction is proposed to investigate thedynamic behavior of a high-speed train running on a track in crosswinds. The model is composed of atraintrack interaction model and a trainair interaction model. The traintrack interaction model is built onthe basis of the vehicletrack coupled dynamics theory. The trainair interaction model is developed basedon the train aerodynamics, in which the Arbitrary LagrangianEulerian (ALE) method is employed to dealwith the dynamic boundary between the train and the air. Based on the airtraintrack model, characteristicsof flow structure around a high-speed train are described and the dynamic behavior of the high-speed trainrunning on track in crosswinds is investigated. Results show that the dynamic indices of the head car arelarger than those of other cars in crosswinds. From the viewpoint of dynamic safety evaluation, the runningsafety of the train in crosswinds is basically controlled by the head car. Compared with the generally usedassessment indices of running safety such as the derailment coefficient and the wheel-load reduction ratio,the overturning coefficient will overestimate the running safety of a train on a track under crosswindcondition. It is suggested to use the wheel-load reduction ratio and the lateral wheelrail force as thedominant safety assessment indices when high-speed trains run in crosswinds.