• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1943-1952
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• 2011

Rail vehicle brakes partly or completely transform the kinetic energy of moving vehicles into other forms of energy, in order to reduce the speed, and if necessary to bring them to a halt. To fulfil these requirements, the effect of a certain brake force is necessary and especially it is considered that the brake force is a important device to rail vehicles as a mass transit. The brake distance is a criterion for measuring brake force. The brake force is measured via dozens of brake distance test before its service operation. The brake distance is influenced by cars and rail conditions; weight of cars, speed on the verge of braking, temperature of brake disk and condition of the upper side of rail, etc. Therefore we will study how the these factors impact with the brake distance via a real test results.

• Journal of the korean Society of Automotive Engineers
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• v.2 no.2
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• pp.21-24
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• 1980

차량의 제동장치는 제동시 차량의 조향안정성을 유지하면서 최소한의 제동거리를 확보하는 장 치라 할 수 있다. 제동시 차량의 조향안정성 유지와 최소제동거리를 확보하기 위해서는 차량의 적절한 제동능력에 필요한 전제동토오크를 전후륜의 제동장치에 적당하게 배분시켜야 한다. 그러나 차량의 각차륜의 하중 상태는 여러 가지 적재상태와 제동시중량이동 등에 따라 변하게 되므로 고정된 제동장치로서는 전후륜의 제동토오크를 가변시킬 수 없어 설계시 빈도가 높은 조건에 맞추어 제동장치의 구성부품을 확정할 수밖에 없다. 차량에 따라서는 축하중상태의 변 화가 큰 경우와 공용화를 위하여 여러 모델의 차량에 동일제동 장치를 적용하려고 할 경우에 문제점이 따르기 마련이다. 본고에서는 제동장치의 전후륜의 제동토오크 배분에 대하여 고찰하여 설계개념을 파악하고자 한다.

• Journal of Korean Society of Transportation
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• v.29 no.3
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• pp.115-122
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• 2011

This paper investigates the accuracy of the vehicle pre-braking speed estimated based upon measured skidding distance. Driver ordinarily takes sudden braking when urgent situation is developed in the front or when the driver is involved in an unexpected situation, and the driver may be inflicted upon an accident depending on the required stopping distance. Among factors influencing the stopping distance of vehicle such as recognition response time of driver, performance of vehicle's braking device, and state of road surface etc, pre-braking speed is seemingly the most important influencing factor. Currently, in the investigating section of traffic accidents, the state of overspeed is determined by the pre-skidding speed calculated based on the length of skid mark. In order to identify the accurate cause of the accident, it is strongly recommended that estimation of pre-braking speed should be estimated taking into account speed reduction during transient time. In this study, we propose a method for estimating more accurate exact speed information of vehicle at the time of traffic accident. The outcomes from this study potentially help better understanding of the characteristics of vehicle for traffic safety in the future.

• Proceedings of the Korea Contents Association Conference
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• 2016.05a
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• pp.427-428
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• 2016

본 논문은 차량 간 통신을 이용해 차량 간 거리를 줄임으로써 도로의 용량을 증가시키기 위한 효과적인 방법을 제공한다. 차량 간 거리는 차량의 제동능력에 의해 결정된다. 편대운항시스템의 차량 간 통신을 이용해 제동능력에 관련된 계수를 공유함으로써 서로간의 제동거리를 알 수 있다. 따라서 서로의 제동능력을 확인 후 차량 간 최소 거리를 측정하여 도로의 용량을 증가시킬 수 있다.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.350-357
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• 2001

본 논문은 고정폐색구간에서 차량운전 특성과 속도패턴이 다양한 다종의 열차들이 동일선로에서 복합되어 고밀도 운행을 위한 방법으로, 신호현시에 대한 제반정보를 차상으로 전송 받아 기관실 신호표시반에 신호를 현시 하는 차상신호방식(Cab Signalling System)중에서, 선행열차의 위치, 선로조건 등 지상의 상태정보를 후속열차가 수신하여 열차 자신의 제동특성 등 차량정보와 비교 분석하여 제동거리를 계산하는 distance to go 방식으로 열차운전속도를 제어하는 ATP (Automatic Train Protection) 시스템을 제안하였다. 폐색구간별 고정된 신호속도단계가 부여되는 ATC(Automatic Train Control) 시스템에서는 운행패턴이 같은 단일차종의 열차만 운행하는 구간에서는 일정속도에 의한 폐색구간 분할로 구간내 distance to go 신호체계가 이루어지지만, 차종과 속도패턴이 서로 상이한 복합열차들의 운행구간에서는 안전거리 확보를 위하여 저속열차의 제동거리를 기준으로 폐색구간 분할 및 속도결정이 이루어지므로 ATP 방식보다 운행효율이 다소 떨어짐을 알 수 있었다. 이를 차량특성과 속도패턴이 다른 3개의 열차를 모델로 하여 열차별 감속도에 의한 제동특성을 ATC와 ATP 신호제어체계에 접목시켜 시뮬레이션을 하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.407-410
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• 2011

본 연구에서는 탑승객의 안전과 국내 환경에 적합한 제동거리 확보를 위해 새로운 개념의 스프링을 사용한 제동장치를 설계하고자 한다. 새로운 제동장치에 사용되는 스프링은 변위에 따라 감쇠 성능 특성을변화시키는 Multi-Rate 변위 감응형 스프링을 최적화하여 적용하였다. 이를 위한 최적화 기법으로는 비선형 최적화 기법인 순차적 2차계획법(Sequential Quadratic Programming, SQP)을 사용하였으며 먼저 Ziprider의 운동을 제동거리와 제동시 발생하는 회전각의 관계로 표현 가능한 수치모델을 개발하였다. 또한 개발된 수치모델은 Matlab을 이용하여 코드화하고 그 결과를 RecurDyn과 비교 분석하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.752-757
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• 2008

In this paper, studied Measuring Equipment for Brake Test provided to test a braking distance and stability on various conditions while at stop/drive. It ensures an objectivity, repeatability and reproducibility for a brake test, which may be applied to various types of braking distance and stability tests anywhere in the world. With Measuring S/W for Brake Test mounted on the vehicle while at stop/drive, braking distance and stability were examined under conditions specified of NCAP and vehicle manufactures A and B's own test, which was available under all conditions and even harder ones to confirm this measuring S/W for brake test be applicable for any changed conditions for the future.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1624-1633
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• 2009

Brake system in railway train operates to reduce the speed of the train or to stop the train via changing the kinematic energy into heat energy for emission and so brake system makes an important rule to transport passenger and cargo for safety operation. Recently operators have a matter of grave concern for the verification of performance in brake system. To verify the exact performance of brake system, most of brake test has been carried out on real operating track condition. Therefore we will determine the braked weight of indirect brake system applied in Iran DMU(Diesel Multiple Unit) in accordance with mc leaflet 544-1, which is to enable Iran DMU to achieve the required braking distances in defined situation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.545-551
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• 2016

In this study, we evaluate the braking performance of an urban railway vehicle to verify its basic safety condition. The braking performance evaluation methods, deceleration measurement and braked weight percentage, were compared for trains with different numbers of cars, in order to assess the advantages of each method and their compatibility. With a probabilistic braking model, the effect of the adhesion coefficient distribution was analyzed in accordance with the train composition. A train with many cars has a narrower deceleration distribution width than one with few cars. The braked weight percentage method is expected to be useful in the design of train signal systems, because it allows the braking distance to be calculated for various initial brake velocities. The deceleration distribution model and its results are expected to be useful as a basis for precise train signal design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.887-895
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• 2018

This paper presents a braking model that can be used to design the safety distance of a train control system and a train braking system to increase the volume of traffic. For the braking model, a train set (electric multiple unit composed 6 cars) was tested. The factors that can affect the braking characteristics include the friction coefficient, braking pressure, and regenerative braking. The braking pressure was classified into service and emergency braking and reflected the characteristics of the vehicle. The external force acting on the running railway car was tested in accordance with KS R 9217, and the running resistance of the train is presented in the form of a polynomial. The dynamic behavior of the train running on a straight flat line was simulated using UM 8.3. The results were validated with experimental data, and the results were reasonable. With the validated model, a stopping distance was determined according to the initial braking speed and compared with the deceleration braking model. In addition, a safety distance for the train control system could be changed according to the frictional coefficient limits. These results are expected to be useful for analyzing the dynamic behavior of trains, and for analyzing various railway environments and improving the braking performance.