• Tribology and Lubricants
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• 제14권1호
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• pp.70-78
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• 1998

Two different friction materials (organic and low-metallic pads) for automotive brakes were studied to investigate the anti-fading phenomena during stop. The anti-fading phenomena were pronounced more in the case of using low metallic friction materials than organic friction materials. The main cause of the anti-fading phenomena was the high dependence of friction coefficient on a sliding speed. The anti-fading was prominent when the initial brake temperature was high in the case of low-metallic friction materials due to the strong stick-slip event at high temperature. On the other hand, the anti-fading was not severe in organic friction materials and the effect was reduced at high braking temperature due to the thermal decomposition of organic friction materials. The strong stickslip phenomena of low metallic friction materials at high temperature induced high torque oscillations during drag test. During this experiment two different braking control modes (pressure controlled and torque controlled modes) were compared. The type of the control mode used for brake test significantly affected the friction characteristics.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권9호
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• pp.431-437
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• 2001

Since the eddy current problem usually depends on the geometry of the moving conductive sheet and the shape of the pole projection area, there is no general method to find out its analytical solution. The analysis of the eddy current in a rotating disk is performed in the case of time-invariant field to find its analytical solution. As a method to solve the eddy current problem, the concept of the Coulomb charge and image method are proposed with the consideration of the boundary condition. Firstly, the line charge is obtained from the volume charge generated in the rotating disk and Coulomb's law is applied. Secondly, the finite disk radius is considered by introducing an imaginary eddy current to satisfy the boundary condition that the radial component of the eddy current is zero at the edge of the relating disk. Thirdly, the braking torque is calculated by applying Lorentz force law. Finally, the computed braking torque is compared with the measured one As a result, it can be said that the proposed model presents fairly accurate results in a low angular velocity range although a large error is observed as the angular velocity of the disk increases.

• 대한기계학회논문집A
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• 제27권9호
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• pp.1492-1498
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• 2003

This study proposes a new conceptual Hybrid Electric Brake System (HEBS) which overcomes problems of a conventional hydraulic brake system. HEBS adopt a contactless type bake system when a vehicle speed is high, to obtain superior braking performances by eddy current. On the contrary, when a vehicle speed is low, HEBS employs a contact type brake system such as conventional hydraulic brake system to generate higher brake force. Therefore, HEBS transfers faster the braking intention of drivers and guarantees the safety of drivers. Braking torque analysis is performed by using a mathematical model which is proposed to investigate the characteristic of a vehicle dynamics when the brake torque is applied. Optimal torque control is achieved by maintaining a desired slip corresponding to the road condition. The results show that HEBS reduces the stopping distance, saves the electric energy, and increases the stability.

• 한국안전학회지
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• 제8권2호
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• pp.23-29
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• 1993

In this study, the method of deciding simulation test conditions is developed by computer program compared to actual vehicle test as accurately as possible. These results of analytical test conditions are conformed by simulation test using the brake dynamometer by comparison with test results of actual vehicle. Results of simulation test by these analytical results show good agreement with the vehicle test results. The analytical simulation test conditions provide the input data to brake dynamometer which follows : - each test inertia corresponding to braking deceleration - test condition of input control : brake line pressure - test condition of output control : braking torque

• 한국산학기술학회논문지
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• 제14권2호
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• pp.822-827
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• 2013

본 논문에서는 정지시까지 전기제동을 하는 축소모형 추진시스템을 설계하고 제작하여 실험하였으며, 정지순간 제동토오크의 제어방법을 제안하였다. 또한, 레졸바를 사용한 회전자의 위치와 속도를 추정하는 관측기에 의하여 극저속에서 속도를 검출하는 방법을 개발하였으며, 또한 정지순간 제동 토오크의 감소와 동시에 공기 브레이크의 동작을 개시하여 블렌딩 제동을 사용하는 방법과 비교하여, 정지시까지 전기제동만을 사용하는 향상된 제동방법을 제안하였다.

• 한국소음진동공학회논문집
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• 제27권2호
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• pp.175-181
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• 2017

In the present work, to achieve high braking performance with restricted size, characteristics of magneto-rheological (MR) fluid brake is numerically investigated considering different magnetic core shapes. As a first step, structural configuration of the MR brakes are proposed with four different magnetic core shapes, such as single flat, single inclined, dual flat and dual inclined. To estimate braking performance of the proposed MR brakes, electromagnetic analysis is carried out and the results of magnetic field intensity distribution are observed. Based on the electromagnetic analysis results, braking torque of the MR brake is estimated according to magnitude of current input and results are discussed. It is observed that enhanced braking torque can be achieved by adopting the modified magnetic core shape under limited small size of the MR brake.

• 한국산학기술학회논문지
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• 제14권1호
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• pp.363-368
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• 2013

영구자석형 동기전동기에 벡터제어를 적용하여 정지시까지 전기제동을 하였으며, 속도검출기는 레졸바를 사용하여 제어기에서 관측자에 의한 위치와 속도를 추정하는 방식을 제안하였다. 또한, 정지직전의 극저속에서 속도에 의한 제동 토오크를 제어하는 방법으로 정지시까지 전기제동을 하였다. 그 결과 제륜자의 소모율 저감과 유지보수성을 증대시키고 소음 및 분진발생의 저감, 승차감과 에너지 사용효과를 향상시켜 전동차의 성능을 향상 시켰음을 알 수 있었다.

• 전기전자학회논문지
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• 제21권3호
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• pp.174-184
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• 2017

본 논문은 철도 차량용 electro-mechanical brake (EMB)의 클램핑 포스 과도응답 향상을 위한 토크 예측 제어 방법을 제안한다. 일반적으로 철도 차량에는 공압식 제동 시스템이 사용된다. 공압식 제동 시스템은 외부환경 변화에 민감하며, 과도응답 속도가 느리기 때문에 공주시간이 증가한다. 또한, 긴급 제동과 같은 기준 이상의 제동 토크를 인가하는 경우에 제동 효율이 낮은 단점이 있다. 이러한 공압식 제동 시스템의 단점은 철도 차량용 EMB 시스템을 적용하여 극복할 수 있다. 철도 차량용 EMB 시스템은 차량의 축중을 감소시키고, 설계 공간을 확보하기 때문에 연비 증가 및 설계 유연성 확보 등의 장점을 갖는다. 본 논문에서는 철도 차량용 EMB의 클램핑 포스 과도응답 향상을 위한 제어 방법을 제안한다. 제안하는 제어 방법의 타당성은 시뮬레이션을 통해 검증한다.

• 한국자동차공학회논문집
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• 제16권1호
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• pp.166-174
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• 2008

Recently, the automotive industry has been developing rapidly. With the progress parts of the automobile components need high quality and the reliability. Among them, braking unit is essential device, and acquire the reliability through the performance test of brake. This study was aimed to design the performance-test-bench to measure the drag torque which has effect on caliper in braking unit. In this progressive technology, it is vital importance to use hydraulic and pneumatic, and to combine test bench with instrumentation engineering technology. This system to construct the design of hydraulic and pneumatic circuit, interface technique between sensors and personal computer, data acquisition and display design, and integrated control are very important technology. Moreover, reliable data are obtained through vacuum system and hydraulic and pneumatic system by using of booster and brake master cylinder which are actually applied to automobile. Then, data signal detector sensors for speed, pressure and torque is attached on this system. Therefore, in this study, we designed a performance-test-bench by and we also made an total control system using personal computer which is more progressive and flexible method than existing PLC control.

• 전력전자학회논문지
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• 제15권4호
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• pp.335-341
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• 2010

전기제동 시스템(Electric braking system)은 기존 자동차 시스템에서 사용된 유압 브레이크를 대신하여 전동기를 이용하여 제동력을 얻게 된다. 전기제동은 기존 유압식에 비해 부품의 수가 감소되며 ABS, ESC 등의 응답성 향상 및 제동거리 감소효과를 얻을 수 있다. 본 논문에서는 EMB(Electro-Magnetic Brake)용 BLAC 전동기의 제어기를 개발하였다. 제어 시스템은 BLAC 전동기 구동을 위한 전력변환장치와 속도제어를 위한 디지털제어기로 구성되었으며, 빠른 토크 응답특성을 위해 벡터제어 기법을 적용하였다. 또한 Matlab/Simulink를 이용한 시뮬레이션 및 실험 결과를 제시하여 EMB용 BLAC 전동기의 성능을 검증하였다.