• Journal of the Korean Society for Railway
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• v.16 no.4
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• pp.253-261
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• 2013

According to the measured results of KTX brake squeal noise in this study, high level brake noise occurred in a wide frequency range, 100~18,000Hz. To identify the sources of the brake squeal noise, unstable vibration modes due to brake disc/pad interaction were analyzed under various conditions by the finite element method. Complex eigenvalues for a brake unit with a disc and four pads were obtained. It was found that the real parts of the complex eigenvalues, that is, unstable vibration modes, were closely related to friction coefficients, pressure on the brake cylinders, elastic moduli of the components, and other conditions.

• Journal of IKEEE
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• v.28 no.3
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• pp.382-389
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• 2024

In this paper, a design of dynamic braking resistor for stationary mode of azimuth driving equipment (ADE) for multi-function radar (MFR) is presented. The ADE carries out missions which is the rotation mode for all directions and the stationary mode for tracing a subject with standstill. The ADE has to transfer the operation mode in demand time from rotation mode to stationary mode for precise target tracing. During the transition with deceleration, it may cause the fault of input power device due to back-electromotive force (back-EMF) of PMSM with generator mode. To protect the power device, a design of dynamic braking resistor is essential for consuming back-EMF. This paper presents the development of dynamic braking resistor for consuming back-EMF of ADE with deceleration mode. The validity and effect of the design is verified using simulation results.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.8
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• pp.485-494
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• 2016

In this work, we conducted a study of fuel consumption characteristics and regenerative braking recovery rate by conducting an experiment using a TMED type parallel hybrid electric vehicle. As regenerative braking technology is considered essential to improve the energy efficiency of the hybrid vehicle, it is necessary to conduct research on the regenerative braking system. Therefore, the electrical characteristics, current balance, and fuel consumption were investigated using an EC type chassis dynamometer with experimental conditions as per IM240 mode. From the results, it was observed that when the initial SOC condition was lower, the engine operating time of the hybrid vehicle increased, and the energy efficiency decreased. While operating in the driving mode characteristics condition and the driving characteristics condition, the difference in the average fuel consumption was not significant. However, after completion of the experiment, there was a difference in the engine operation.

• Annual Conference of KIPS
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• 2023.11a
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• pp.1141-1142
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• 2023

본 연구는 4륜 독립 구동·제동·조향 차량의 모드 천이 논리 알고리즘에 관한 연구로서, 일반적인 주행 스타일 외에도 다양한 주행 스타일을 가지는 차량에서 주행 모드 전환 간에 고려되어야 하는 조건들을 다룬다. 주행 모드 전환 간에 Static Transition과 Dynamic Transition이 가능하며 Static Transition 방식이 일반적이지만 저속 상태에서 차량이 충분히 정렬되어 있다면 FWS 주행, 동상 주행, 역상 주행 간의 Dynamic Transition도 가능할 것이다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.10
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• pp.1005-1013
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• 2009

In this paper, the performance improvement of a decentralized brake system for railway rolling stocks is investigated. In order to verify the effectiveness of the decentralized brake system, it is compared to the truck unit brake system which has only one control unit per a truck. The adaptive sliding mode control scheme is used to realize a robust anti-slip brake control system. Through computer simulations, it is verified that the decentralized brake system has better braking performance than the truck unit brake system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.733-736
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• 2002

This study was carried out to investigate the braking performances associated with the friction coefficients and temperature fluctuations. Friction coefficient stability and maximum temperature of brake drums, made of an Al-MMC and conventional cast iron, were tested by the inertial brake dynamometer during 15 braking operations. Also the temperature distribution was analyzed by the finite element analysis(FEA). In this experiment, both lower temperature rise near the drum surface and less variation of friction coefficient, compared to those of cast iron, were observed with Al-MMC drums during braking operations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.668-669
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• 2016

The retarder as a hydraulic brake system in order to assist a service brakes in commercial vehicle is operated by automatic and manual mode due to driver. Braking energy by retarder operation is transmitted to the engine radiator of vehicle cooling system, passing through the retarder oil heat exchanger. At this moment, the retarder ECU performs the function that is controlled a braking torque with consideration for automatic and manual mode, temperature of retarder oil/water, engine coolant temperature, vehicle speed, and etc. In this paper, it deals with the design of retarder control logic and the results of retarder braking performance test regarding a cooling system of retarder and vehicle.

• Journal of Energy Engineering
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• v.20 no.4
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• pp.286-291
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• 2011

The hybrid vehicle has a good fuel economy with a electric type braking energy regeneration system. This paper introduced a novel pneumatic type braking energy regeneration system. The novel system use a scroll mechanism which have both compression function and expansion function. While vehicle is decelerating, the scroll machinery, being operated as a scroll compressor, compress a atmospheric air to save the vehicle's kinetic energy and reuse a compressed air which is reserved in a air tank while vehicle is accelerating. In order to analyze fuel improvements by applying braking energy regeneration system to a vehicle, we simulated the rate of braking energy regeneration through CVS-75 mode driving patterns.

• Annual Conference of KIPS
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• 2023.11a
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• pp.1145-1146
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• 2023

모빌리티 기술이 발전함에 따라 기존 차량에서 선보이지 못했던 다양한 주행기술이 가능해졌고, 이에 따라 많은 장점을 지닌 모빌리티 기술들이 등장하고 있다. 4 륜 독립 구동, 제동, 조향 시스템은 바퀴 별 독립 제어가 가능하여 여러 주행 모드를 구현할 수 있다. 본 연구에서는 4 륜 독립 구동, 제동과 독립 조향이 가능한 모빌리티 플랫폼에 대해 평행 주행, 제자리 회전, 축 회전 주행 등을 구현하는 방안과, 더 나아가 각도 속도를 일정하게 유지함으로써 오차를 최소화하는 제어 방법에 대해 살펴보고자 한다.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.495-496
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• 2015

본 논문에서는 양수발전용 동기발전기의 기동 및 회생제어를 위한 부하전류형 인버터(LCI) 시스템을 Matlalb/simulink를 이용하여 모델링하고 제어방법을 확인하였다. 부하전류형 인버터의 구성 및 동작모드에 대해 서술하였으며, 동기발전기의 안정성 확보를 위한 회생제어 모드에 적합한 제어 방법을 제안하였다. 제안된 방법은 기존의 복잡한 제어구조와 달리 제어요소의 간략화로 제어의 강인성을 확보하였으며, 부하전류형 인버터 시스템의 기동제어 및 제안된 회생제어에 대한 성능은 시뮬레이션을 통해 검증하였다.