• 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 KIEE Conference
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• 2003.07d
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• pp.2025-2027
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• 2003

미끄럼방지 제동장치는 차량의 급제동 시 바퀴의 장김을 방지하여, 바퀴의 슬립을 최적으로 유지 시킴으로써 제동거리를 단축시키고, 운전자가 차량 조향성을 유지할 수 있게 만드는 차량 안정장치이다. 이 장치는 비행기의 착륙거리를 줄이기 위해 개발된 이래로, 철도 및 차량 등에도 널리 적용되고 있으며, 국내에서도 이미 승용차를 위주로 양산되고 있는 추세이다. 이러한 미끄럼방지 제동 장치는 공압 브레이크 장치를 사용하는 대형차량 분야에서는 아직 국내에서 적용된 사례가 없었으나, 지난 3 년간의 연구개발의 성과로 대형 버스에 적용 가능한 미끄럼방지 제동장치의 전자제어기가 개발 완료되었으며, 국제 규격을 바탕으로 국내 현실에 적합한 미끄럼방지 제동장치 장착 대형차량의 시험 규격을 정하여 이 규격에 의거 제동시험을 실시하고 개발 제어기의 성능을 평가하였다. 각 제동 시험은 $\mu$-Jump 제동시험 및 Split-$\mu$ 제동시험 등의 직진 주행 중 급제동시험, 급제동 중 차선변경 시험, 장애물 회피 제동시험 등을 포괄하며 국제적인 규격을 기준으로 정한 독자 규격을 만족하였다. 본 논문에서는 공압 브레이크를 장착한 대형차량의 미끄럼방지 제동장치의 제동성능평가 시험방법을 소개하고, 이 방법에 의해 성능평가 시스템 및 측정 시스템을 구성하여, 개발 전자제어기의 우수성을 확인하였으며, 그 측정결과의 일부를 제시하였다.

• 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.

• Journal of the Korean Society for Railway
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• v.11 no.2
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• pp.188-194
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• 2008

Brake disks for rolling stock are exposed to thermal fatigue during braking, and thermal cracks occur on surface of disks. Thermal cracks can cause serious accidents, deterioration of braking performance and increase of maintenance cost due to frequent exchange of friction materials. In this study, candidate materials with high-heat resistance were selected by searching the literature. By using cast specimens made of the candidate materials, chemical composition, crystal structure and graphite type were analyzed. In addition, friction coefficient and wear were measured and compared with values for the disk material in service. As a result, it was shown that the NiCrMo has highest tensile strength and lowest friction coefficient and the disk material in service has the most stable friction characteristics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.170-177
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• 2020

This study examined the clamping force control method and the braking performance test results of an electromechanical brake (EMB) using braking test equipment. Most of the studies related to EMBs have been carried out in the automotive field, dealing mainly with the static test results for various control methods. On the other hand, this study performed a dynamic performance evaluation. The three-phase interior permanent magnet synchronous motor (IPMSM) was applied to drive the actuator of the EMB, and the analysis was verified by JMAG(Ver. 18.0), which is finite element method (FEM) software. The current control, speed control, and position control were used for clamping force control of the EMB, and the maximum torque per ampere (MTPA) control was applied to the current controller for efficient control. The EMB's emergency braking deceleration performance was tested in the same way as conventional pneumatic brake systems when the wheel of a train rotates at 110 km/h, 230 km/h, and 300 km/h. The emergency braking time, with the wheel stopped completely at the maximum rotational speed, was approximately 73 seconds. The similarity of the braking time and deceleration pattern was verified through a comparison with the performance test results of the pneumatic brake system applied to the next generation high-speed railway vehicle (HEMU-430X).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.541-549
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• 2018

This paper deals with the braking dynamic behavior of diesel electric locomotive pulling domestic cargo and passenger vehicles. Friction coefficient, pneumatic pressure, and running resistance affecting the braking system were tested. For the friction coefficient, the Dynamo test was performed with reference to UIC 541-4. The results are analyzed by multivariate regression and the relationship between braking force and ititial velocity is presented. The pneumatic pressure were classified into service braking and emergency braking. In order to reflect the characteristics of the brake valve and piping, the pressure rising over time was measured in the vehicle. In order to reflect the external force acting on the vehicle, we carried out the test of EN 14067-4 and presented the second order polynomial formula on a running resistance. The running resistance test results were compared with other countries. The dynamic behavior of a diesel electric locomotive running on a straight flat track based on vehicle resources, friction coefficient, braking pressure, and running resistance is simulated using the time integration presented in EN 14531-1. The simulation results were compared and verified with the vehicle braking test results. The results of this study can be used to analyze the dynamic braking behavior of a train. Also, it is expected that various parameters affecting braking in vehicle design can be analyzed and used as basic data for braking performance improvement.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.238-238
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• 2003

• Journal of the Korean Society for Railway
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• v.20 no.1
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• pp.1-10
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• 2017

Brake squeal noise has been a challenging problems for a long time. It is very annoying to passengers and residents near tracks. Two methods have been applied to reduce or eliminate brake squeal noise. One is to improve frictional materials; the other is to optimize the topology and structures of brake pads. In this study, we developed two kinds of brake pads; one is a pad whose frictional material is different from the KTX brake pad friction material; the other is a flexible pad that has the same frictional material as that of the KTX brake pad, but a different structure. Squeal noise and friction coefficients were measured and analyzed using a full-scale brake dynamometer. It was found that the dynamometer test can simulate the squeal noise of KTX trains at stations. The squeal frequency of the KTX at 4500Hz was exactly reproduced; this value of 4500Hz was one of the natural frequencies of the KTX brake disc. It was also found that the squeal noise depended on the caliper pressure, initial disc temperature and braking speed. The average friction coefficient was 0.35~0.45. The new pad lowered the squeal noise by 17.3~21.6dB(A).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.32-38
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• 2020

Cargo train braking uses the pressure changes in the air braking pipe to operate the braking tightening and releasing service repeatedly. Air-braking release failure means partial braking caused by a failure of the variable load valve after the driver handling the brake release. This phenomenon causes wheel flaws while driving a wagon, resulting in wheel breakage or train derailment. This study developed the air-braking release failure proof valve considering the technical requirements of the railway operation corporations. In addition, a durability test of the valve was carried out using a braking performance simulator, and its operating performance was evaluated from the pneumatic history under cyclic braking conditions. The warranty life of this valve was assessed by performing 160,000 cycles of testing of 12 prototypes in accordance with the zero-failure test method, considering the number of braking cycles while driving the wagon. During the durability test, the pneumatic input time, output time, and release velocity were almost constant. The warranty life of this valve was 59,860 times the 95% confidence level, which means that it can be operated without trouble for four years when the valve is installed in the bogie of the wagon.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.821-827
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• 2023

In this study, the aircraft technical standards of the Korea and the United States were analyzed to derive the dynamometer test procedure required to prove the compatibility for flight test certification of the metal brake pad for transport aircraft. Since the design modification of the brake systems is classified as a major change, the STC(Supplemental Type Certificate) and the PMA(Parts Manufacturer Approval) are required. In accordance with the TSO-C135a, the technical standard order for brake system in the United States, the design landing-stop test, accelerate-stop test, and most severe landing stop test were selected among the test items for flight test. The conditions for the dynamometer test are determined according to the specifications provided by aircraft manufacturer, and the brake pad condition, deceleration, and the number of test are defined according to the TSO-C135a.