• 대한기계학회논문집A
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• 제30권3호
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• pp.295-301
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• 2006

The wheel slip control systems are able to control the braking force more accurately and can be adapted to different vehicles more easily than conventional ABS systems. In order to achieve the superior braking performance through the wheel-slip control, real-time information such as the tire braking force at each wheel is required. In addition, the optimal target slip values need to be determined depending on the braking objectives such as minimum braking distance, stability enhancement, etc. In this paper, a robust wheel slip controller is developed based on the adaptive sliding mode control method and an optimal target slip assignment algorithm. An adaptive law is formulated to estimate the longitudinal braking force in real-time. The wheel slip controller is designed using the Lyapunov stability theory and considering the error bounds in estimating the braking force and the brake disk-pad friction coefficient. The target slip assignment algorithm is developed for the maximum braking force and searches the optimal target slip value based on the estimated braking force. The performance of the proposed wheel-slip control system is verified In simulations and demonstrates the effectiveness of the wheel slip control in various road conditions.

• International Journal of Automotive Technology
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• 제8권2호
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• pp.211-217
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• 2007

The wheel slip control systems are able to control the braking force more accurately and can be adapted to different vehicles more easily than conventional ABS (Anti-lock Brake System) systems. In realizing the wheel slip control systems, real-time information such as the tire braking force at each wheel is required. In addition, the optimal target slip values need to be determined depending on the braking objectives such as minimum braking distance and stability enhancement. In this paper, a robust wheel slip controller is developed based on the adaptive sliding mode control method and an optimal target slip assignment algorithm is proposed for maximizing the braking force. An adaptive law is formulated to estimate the braking force in real-time. The wheel slip controller is designed based on the Lyapunov stability theory considering the error bounds in estimating the braking force and the brake disk-pad friction coefficient. The target slip assignment algorithm searches for the optimal target slip value based on the estimated braking force. The performance of the proposed wheel slip control system is verified in HILS (Hardware-In-the-Loop Simulator) experiments and demonstrates the effectiveness of the wheel slip control in various road conditions.

• 대한교통학회지
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• 제27권1호
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• pp.43-51
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• 2009

이 논문은 타이어-노면간 마찰계수(drag factor)와 노면에 발생된 스키드마크를 통해 제동직전 속도(pre-braking speed) 산정을 정확하게 하기 위한 방법론을 제시하고자 한다. 제동직전 속도(pre-braking speed)와 활주직전 속도(pre-skidding speed)간 어떠한 상관관계가 있는지 판단하기 위해 실차 주행 및 제동실험을 통해 데이터가 수집되었다. 두 대의 차량에 fifth wheel(오륜) 장비, 스피드건, vericom 2000 등 다양한 측정장비를 탑재하여 제동실험이 수행되었으며, 자동차 속도, 제동거리, 활주거리, 감속도 등이 정밀 측정되었다. 실험자료의 분석을 통해 노면 마찰계수값과 활주직전 속도를 산정하고, 이후 활주직전 속도와 제동직전 속도를 비교하여 이들간의 상관관계를 규명하였다. 결과적으로 산정된 마찰계수값은 현재 일반적으로 적용되고 있는 0.8보다 높았으며, 제동직전 속도는 활주직전 속도보다 $5{\sim}10km/h$ 정도 높은 것으로 나타났다. 향후에는 다양한 차종과 노면조건에 대한 후속실험을 통해 더욱 정교한 한국형 분석모형의 개발과 실무적용이 필요할 것으로 판단된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1049-1058
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• 2011

This paper suggests blending time adjusting method of braking command characteristics management and Set value test for optimizing of braking deceleration to enhance the precise position stopping. This method minimizes pneumatic-braking degree deviation by characteristics management, and secures braking stability at braking. By Set value test method, braking blending characteristics are analyzed accurately. And by optimal timing tuning at braking blending, It enhanced the precise position stopping with stabilization of deceleration To demonstrate the usefulness of these suggestion, I modeled for Deajeon Line #1. And through comparison with case of related companies, the proposed method which this paper suggested is proved to be superior to others.

• 전력전자학회논문지
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• 제7권4호
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• pp.313-321
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• 2002

영구자석 동기전동기의 제동 알고리듬을 제안한다. 전동기의 고정자 저항을 제동저항으로 사용함으로써 전동기의 운동에너지를 부가적인 제어회로 없이 고정자권선에서 소모한다. 제안된 제동 알고리듬은 고정자권선에서 전력소모를 최대화하고 DC 링크 콘덴서전압 제한 및 인버터 전류제한 조건하에서 최대의 제동토크를 발생하여 제동시간을 최소화 할 수 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.103-108
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• 2005

Since the braking system of rolling stock is directly linked to it's safety, ensuring reliability of braking system and evaluation of performance of it are very important. To develope the performance of braking system, it is required advanced technology and gradually various factors in the field test result. This study is designed to analyze the air pressure control about braking force in rolling stock, also, by comparing braking force of KTX with that of high speed train. This paper suggests to establish a method of computation of braking force form the air pressure control. And The high speed train researches into patterns of braking system such as the train of speed up and introduction of electric and pneumatic braking system.

• 한국자동차공학회논문집
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• 제21권1호
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• pp.17-22
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• 2013

Design of braking system is one of the most critical subjects in vehicle stability. In this paper, optimal scheme for brake force proportioning of all-wheel-drive vehicle is proposed to guarantee the vehicle dynamic stability under plausible drive circumstances. A brake force distribution of generic $8{\times}4$ vehicle is calculated according to proposed scheme and braking stability of this vehicle is verified by using a commercial vehicle software, Trucksim.

• 한국자동차공학회논문집
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• 제11권1호
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• pp.172-178
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• 2003

Driving range is one of the main problems in development of Electric Vehicles(EV). The Regenerative. braking system is required to overcome the problem, which converts kinetic energy of the vehicle during braking into electrical energy. This paper discusses the braking system of EV and Robust design especially developed to maximize energy recovery and to optimize braking performance. This is promised to be applied to the design of elements for EV braking system.

• 한국자동차공학회논문집
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• 제24권5호
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• pp.581-587
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• 2016

Braking is a basic and an important safety feature for all vehicles, and the final braking performance of a vehicle is determined by the vehicle's ABS performance and tire performance. However, the combination of excellent ABS and tires will not always ensure good braking performance. This is due to the fact that tire performance has non-linearity and uncertainty in predicting the repeated increase and decrease of wheel slip when activating the ABS, thus increasing the uncertainty of tire performance prediction. Furthermore, existing studies predicted braking performance after using an ABS that used a wheel slip control as a controller, which was different from an actual vehicle's ABS that controlled angular acceleration, therefore causing a decrease in the prediction accuracy of the braking performance. This paper reverse-designed the ABS that controlled angular acceleration based on the information on brake pressure, etc., which were obtained from vehicle tests, and established a braking performance prediction analysis model by combining a multi-body dynamics(MBD) vehicle model and a magic formula(MF) tire model. The established analysis model was verified after comparing it with the results of the braking tests of an actual vehicle. Using this analysis model, this study analyzed the braking effect by vehicle factor, and finally designed a tire that had optimized braking performance. As a result of this study, it was possible to design the MF tire model whose braking performance improved by 9.2 %.

• 한국자동차공학회논문집
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• 제23권3호
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• pp.344-351
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• 2015

Braking force inspection of vehicles in service is certainly one of the most important characteristics that affect vehicle safety. Up to now, in domestic country, the regular safety inspection of vehicles in service has been tested with a roller type brake test (a static braking force inspection system). But, in EU and USA etc. in recent years, it has been tested with a plate type brake test (a dynamic braking force inspection system). In this study, to compare the characteristics of above two test systems, the correlations for the results of braking force are evaluated statistically. As the results, in the case of main braking force, the range of the $R^2$ of the deviation for the left and right side is 0.5386 ~ 0.6231 in the rear axle and 0.0032 ~ 0.0052 in the front axle respectively, then the $R^2$ in the front axle is lower than that in the rear axle and the total variation is unexplained by the least-squares regression line statistically. Also, the p-value for the deviation of the left and right in the front axle is 0.4839 ~ 0.5755, then it has nonsignificant in the front axle. Therefore, the static braking force inspection system can not reflect the inertia force that there is a load transfer from the rear axle to the front axle during braking. Accordingly, it is necessary to adopt the dynamic braking force inspection system which can reflect the inertia force on the regular vehicle safety inspection in domestic country.