• Title/Summary/Keyword: 노면 마찰

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Effects of Outlet Shape on Vehicle Behavior according to Road Friction Coefficient in Interchange (입체교차로에서 노면 마찰계수에 따른 유출부 형상이 차량거동에 미치는 영향)

  • Park, Hyeong-Seon;Lim, Jong-Han;Yoon, Jun-Kyu
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.16 no.5
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    • pp.213-220
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    • 2016
  • In order to drive on road safely, the type of road design and construction is basically needed to optimize driver's safety and vehicle performance. Although the heavy traffic highways were built by reflecting these factors, the national highways and local roads have still taken a lot of problems. In this study, we analyzed the behavior characteristics of a vehicle according to the speed variation of the vehicle using the PC-Crash program for the traffic accidents reconfiguration at GULUN interchange located Hongcheon in Gangwon Province. the conditions outlet surface of the road for analysis were dry road surface, wet road surface and icy road surface. As a result, we identified the fact that the friction coefficient of road surface and the speed of vehicle affected to vehicle behavior characteristics of outlet shape in GULUN interchange, and showed the possibility that we can verify a problem about road design through to this simulation in advance.

A Study of Skid Resistance Characteristics by Deicing Chemicals (제설제 사용으로 인한 노면 미끄럼저항 특성 연구)

  • Lee, Seung Woo;Woo, Chang Wan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.5D
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    • pp.813-819
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    • 2006
  • Skid Resistance is a index to represent the friction between tire and road surface, which influences driving safety. Skid resistance varies with the conditions of tire, abrasion of road surface, vehicle speed, drying, wet and freezing condition of road surfaces. Especially, freezing occurs when temperature drops below $0^{\circ}C$ followed by snow or rain causes decrease of skid resistance. To recover the decreased skid resistance deicing work is applied. As a results of deicing works, freezing condition is changed into wet condition. However the wet road surfaces containing the remaining deicings agents may not show the skid resistance of normal wet condition. In this study, skid resistances in the condition of freezing, deicing process and deicing agents remained after snow-removal are evaluated. The test results, skid resistance recover quickly when Pre-wetted salt spreading and NaCl was used as deicing method. Skid resistance of Deicing agents remained on the road surface showed that concrete is higher than asphalt. superior effect. Recovery rate of skid resistance by comparison wet condition is 54~80%.

An Experimental Study of Tire-Road Friction Coefficient by Transient Brake Time (실차 실험을 통한 제동순시간에 의한 타이어-노면마찰계수에 관한 연구)

  • Han, Chang-Pyoung;Park, Kyoung-Suk;Choi, Myung-Jin;Lee, Jong-Sang;Shin, Un-Gyu
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.7 s.196
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    • pp.106-111
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    • 2007
  • In this paper, the transient brake time was studied on the van type vehicle with accelerometer. Experiments were carried out on the asphalt(new and polished), unpacked road(earth and gravel) and on wet or dry road conditions. The transient brake time is not effected bzy the vehicle speed. The transient brake time is about 0.41$\sim$0.43second on the asphalt road surface and the error range is within 0.1$\sim$0.16second. For the asphalt road condition, the transient brake time is not effected by both new asphalt road surface and the polished asphalt road surface. With compared by dry and wet road surface condition, the transient brake time of wet condition is longer than dry road condition and compared with unpacked road condition and packed road condition, unpacked road condition is shorter than packed road condition. It is considered that the transient brake time is effected by the road surface fraction coefficient. In other words, the transients brake time increases as friction coefficient decreases.

Estimation of Tire Braking Force and Road Friction Coefficient Between Tire and Road Surface For Wheel Slip Control (휠 슬립 제어를 위한 타이어와 노면 사이의 타이어 제동력 및 노면 마찰계수 추정)

  • Hong, Dae-Gun;Huh, Kun-Soo;Yoon, Pal-Joo;Hwang, In-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.5
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    • pp.517-523
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    • 2004
  • Recently, wheel slip controllers with controlling the wheel slip directly has been studied using the brake-by-wire actuator. The wheel slip controller is able to control the braking force more accurately and can be adapted to various different vehicles more easily than the conventional ABS systems. The wheel slip controller requires the information about the tire braking force and road condition in order to achieve the control performance. In this paper, the tire braking forces are estimated considering the variation of the friction between brake pad and disk due to aging of the brake, moisture on the contact area or heating. In addition, the road friction coefficient is estimated without using tire models. The estimated performance of tire braking forces and the road friction coefficient is evaluated in simulations.

Estimation and Evaluation of Water-film Thickness on Airport Runway according to Climate Change (기후변화에 따른 공항 활주로의 수막두께 산정 및 평가)

  • Park, Se-Min;Kim, Jeong-Bae;Bae, Deg-Hyo
    • Proceedings of the Korea Water Resources Association Conference
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    • 2016.05a
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    • pp.166-166
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    • 2016
  • 국내에서는 기후변화로 인해 집중호우 및 태풍 발생이 증가하고 있으며, 이는 자연재해의 발생뿐만 아니라 차량 및 항공 운항의 어려움을 야기한다. 차량 및 항공 운항의 안정성 확보를 위해서는 노면의 마찰저항을 유지하는 것이 중요한데, 강수로 인해 형성되는 수막두께는 노면의 마찰저항을 감소시키므로 포장설계시 고려해야 할 주요소이다. 특히, 물적/인적 이동이 많은 공항은 기상조건에 더욱 취약하며, 기후변화로 인한 강수특성 변화로 활주로의 수막두께 증가 및 운항의 차질이 우려되고 있다. 따라서 본 연구에서는 과거 및 미래 강우조건에 따라 활주로 노면의 수막두께를 산정하고, 기후변화에 따른 수막두께의 변화를 평가하고자 한다. 과거 관측 및 기후변화 시나리오를 이용하여 강우자료를 생산하였고, 이를 강우-유출 모형의 강우 입력 자료로 활용하였다. 과거 강우자료는 인천지점의 기상청 관측자료를 수집하였으며, AR5 RCP 시나리오(RCP4.5, RCP8.5) 기반의 적정 GCMs 결과를 활용하여 미래 강우시나리오를 산정하였다. 강우의 재현기간 및 지속시간에 따른 수막두께의 변화를 분석하기 위해 인천지역의 과거 및 미래 확률강우량을 산정하였다. 수막두께를 산정하기 위해 활주로 폭, 경사 등 활주로 제원을 수집하고, 유출 모형의 입력자료를 구축하였다. 과거 및 미래 확률강우량을 SWMM 모형에 적용하여 유출량을 산정하였으며, 유속과 흐름폭으로 나누어 활주로의 수막두께를 산정하였다. 산정결과, 강우량이 증가함에 따라 수막두께는 증가하고, 강우의 지속시간이 증가함에 따라서는 감소하는 것으로 분석되었다. 미래의 경우, 기후변화의 영향에 따라 강수량이 증가하여 수막두께가 과거에 비해 증가하였다.

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ABS Sliding Mode Control considering Optimum Road Friction Force of Tyre (타이어의 최적 노면 마찰력을 고려한 ABS 슬라이딩 모드 제어)

  • Kim, Jungsik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.1
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    • pp.78-85
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    • 2013
  • This paper presents the sliding mode control methods for anti-lock brake system (ABS) with the friction force observer. Using a simplified quarter car model, the sliding mode controller for ABS is designed to track the desired wheel slip ratio. Here, new method to find the desired wheel slip ratio which produces the maximum friction force between road and tire is suggested. The desired wheel slip ratio is varying according road and tire conditions to produce maximum friction force. In order to find optimum desired wheel slip ratio, the sliding mode observer for friction force is used. The proposed sliding mode controller with observer is evaluated in simulation, and the control design is shown to have high performance on roads with constant and varying adhesion coefficients.

Developing a Model to Predict Road Surface Temperature using a Heat-Balance Method, Taking into Traffic Volume (교통량을 고려한 열수지법에 의한 노면온도 예측모형의 구축)

  • Son, Young-Tae;Jeon, Jin-Suk;Whang, Jun-Mun
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.14 no.2
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    • pp.30-38
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    • 2015
  • In this study, to improve effectiveness of road management services and the safety of the road in winter, road surface temperature prediction model was developed. We have utilized the existing input data of meteorological data and additional traffic data. This Road surface temperature prediction model was utilizing a Heat-Balance Method additionally considering amount of traffic that produce heat radiation by vehicle-tire friction. This improved model was compared to the based model to check into influence of traffic affecting the road surface temperature. There were verified by comparing the real observed road surface temperature of the third Gyeong-In highway and road surface temperature from the two models. As a result, the error of real observed and the predicted value (RMSE) was found to average $1.97^{\circ}C$. Observed road surface temperature was dramatically affected by the sunlight from 6 a.m. to 2 p.m. and degree of influence decreases after that. The predictive value of the model is lower than the observed value in the afternoon, and higher at night. These results appear due to the shielding of solar radiation caused by the vehicle in the afternoon and at night, the vehicle appeared to cause thermal heat supply.

Friction Coefficient of Emergency Braking on ABS and Non-ABS Car (ABS와 Non-ABS 승용차량의 급제동시 마찰계수 변화)

  • Kim, Kee-Nam;Lee, Ji-Hoon;Ok, Jin-Kyu;Yoo, Wan-Suk;Park, Ji-Yeong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.3
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    • pp.52-59
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    • 2008
  • Most accident reconstruction or analysis depend on the coefficient of friction to estimate the vehicle speeds. Skid mark and coefficient of friction are usually utilized to calculate the velocity and behavior of vehicles. For a critical case such as traffic accident reconstruction, however, the initial velocity of the car should be calculated precisely. In this paper, emergency brake tests on ABS and Non-ABS brake system are conducted on the dry pavement asphalt road on speed 40, 60, 80 and 100 km/h respectively. The SWIFT sensor was established in the front wheel and rear wheel at driver side to measure the forces, moments and speeds of revolution of the tires. These tests results can be available to brake tests and accident reconstruction.