• 대한기계학회논문집A
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• 제24권4호
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• pp.926-936
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• 2000

Actual and strict definition of the shift quality for the powertrain system equipped an automatic transmission must be understood through the acceleration change of the vehicle body, which the driver directly feels as a shift shock. For this reason, it is necessary to concurrently analyze the characteristics of the powertrain system and the vehicle body. This paper presents the mathematical model of the vehicle body, which is based on the equivalent lumped system, to append to the developed model of the powertrain system. The concept of tire slip is also introduced for the experimental relationship between tire/road and driving force. Using the developed dynamic simulation programs, shift transients characteristics are analyzed. Theoretical results are compared with experimental ones from real car tests in equal conditions in order to prove the validity of presented model. In these tests, the system to measure the vehicle acceleration is used with various speeds and engine throttle sensors. It is expected that the presented modeling techniques can provide good predictions of the vehicle driving comfortability.

• 한국자동차공학회논문집
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• 제7권7호
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• pp.136-148
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• 1999

Detailed mathematical models of hybrid drivertrain components are presented and numerical simulations are carried out to analyze the shift characteristics and to improve the driving comfortability when the hybrid drivetrain is applied at the vehicle . Theoretical results are compared with experimental ones from the dynamometer as same condition in order to prove the appropriateness of modeling . Adding the vehicle body modeling, included in the suspension and the engine mount, it is possible to predict the dynamic behavior and shift characteristics more actually when shifts are occurred by automated manual transmission(AMT). these additional results are also compared with the same simulation ones of internal combustion engined vehicle equipped conventional manual transmission. Hence, it can be expected that the hybrid vehicle with AMT has a good shift quality.

• 자동차안전학회지
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• 제14권4호
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• pp.35-42
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• 2022

This paper presents a stochastic model predictive control (SMPC) for stop maneuver of autonomous vehicles considering perception uncertainty of stopped vehicle. The vehicle longitudinal motion should achieve both driving comfortability and safety. The comfortable stop maneuver can be performed by mimicking acceleration profile of human driving pattern. In order to implement human-like stop motion, we propose a reference safe inter-distance and velocity model for the longitudinal control system. The SMPC is used to track the reference model which contains the position uncertainty of preceding vehicle as a chance constraint. We conduct simulation studies of deceleration scenarios against stopped vehicle in urban environment. The test results show that proposed SMPC can execute comfortable stop maneuver and guarantee safety simultaneously.

• 대한교통학회지
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• 제31권5호
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• pp.48-59
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• 2013

본 연구에서는 도로투자 사업으로 인한 편익 중 일반적으로 계상하고 있는 통행시간 절감 및 차량운행비용 절감 등 직접적인 편익 이외에 추가적으로 이용자입장에서 체감할 수 있는 도로 주행 중 운전쾌적성 편익을 산정하고자 운전쾌적성의 정의를 마련하였고 운전쾌적성 산정방법론을 개발하였다. 도로특성(도시부/지방부) 및 차량 밀도(차간거리)에 따른 이용자의 지불용의액을 CVM 방법 중 가장 최근에 활발히 활용되고 있는 이중양분선택형(double-bounded dichotomous choice)질문법을 활용하여 설문조사한 후 그 결과를 로짓모형에 적용하여 운전쾌적성 가치를 도출하였다. 도시부 및 지역간 도로에서 공히 지불용의액의 크기는 전반적으로 기존 차간거리가 짧을수록 큰 것으로 분석되었고, 도로의 차간거리 변화가 같더라도 사업 전의 차간거리와 사업 후의 차간거리에 따라 지불용의액이 다른 것으로 나타났다. 즉, 도로의 차간거리가 증가하더라도 기존 차간거리가 어느 정도인지에 따라 지불용의액이 다르게 나타나 지불용의액이 기존 차간거리에 영향을 받는 것으로 분석되었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1793-1798
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• 2011

The railway structure for a rubber-wheeled automated guide-way transit system consists of a driveway and a guide-way. The most important factor of this system is the driveway and the guide-way aligned with each other, especially for curves and inclines section. The conventional construction method caused many problems such as discordancy by constructing the driveway before constructing the guide-way. Therefore, in this paper we introduce a new method of constructing a railway for a rubber-wheeled light rail vehicle; the new method of constructing the guide-way beforehand as a preceding process. The new method for AGT railway system can simplify the construction process and thus the construction costs may be reduced. It should also improve the driving performance and the comfortability in operating of a light rail vehicle.

• 한국도로학회논문집
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• 제15권3호
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• pp.103-115
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• 2013

PURPOSES: The purpose of this study is to develop a method for distribution between superelevation and side friction factor by increasing design speed. METHODS: First of all, a method for distribution between superelevation and side friction factor and a theory for the functional formula of side friction factor in compliance with horizontal radius applied in South Korea and the United States are considered. Especially, design speed of 140km/h and numerical value of design elements are applied to the theory for the functional formula of side friction factor in AASHTO's methods. Also, the anxiety EEG upon running speed is measured to reflect ergonomic characteristics through field experiments at seven curve sections of the West Coast Freeway, and this data is applied to graph for the functional formula of side friction factor. RESULTS : Matching side friction factor against the anxiety EEG, the results that a critical points of driver's anxiety EEG sharply increase locate under existing parabola are figured out. CONCLUSIONS : Therefore, we could get a new type of the functional formula that driver's driving comfortability is guaranteed if the existing the functional formula of side friction factor goes down under boundary of the critical points of the anxiety EEG.

• 대한의용생체공학회:의공학회지
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• 제41권5호
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• pp.203-209
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• 2020

As the number of people with gait disorders increases, the demand for using wheelchairs increases and the area of a ctivity for people with disabilities expands, thereby they increasing the demand for riding comfortability in various driving environments. Therefore, this study is to develop an entry-level active suspension system that apply to wheelchairs and to evaluate its usability. The suspension applied in this paper consists of a coil spring, a shock absorber, a control module to control the strength of the shock absorber, and a road surface condition monitoring system. A wheelchair occupant secures the riding comfort by adjusting the coil strength of the shock absorber in 12 steps according to various road conditions. Therefore, the mechanical properties were evaluated through the structural analysis of the suspension system, and the tendency toward the magnitude of the road surface vibration attenuated according to the rigidity of the suspension through the vibration test was attempted. In conclusion, as a result of structural analysis of the suspension system, stress in a range lower than the yield strength of the material was generated, and the vibration test showed the effect of attenuating the vibration generated from the road surface when the stiffness of the suspension was adjusted.

• 대한토목학회논문집
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• 제33권6호
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• pp.2493-2501
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• 2013

대도시를 중심으로 승용차 이용을 억제하고 대중교통의 수단분담률을 제고시키기 위한 다양한 교통수요관리방안이 추진되어 왔으나 승용차 통행량의 감소와 같은 정책적인 효과는 충분하다고 볼 수 없다. 이러한 원인의 하나로 대중교통 서비스의 향상을 통해 승용차로부터의 수단전환을 유도하는 정책들이 대중교통의 수단적 효용을 증가시키는 효과는 있었으나 모든 승용차 이용자에게 대중교통으로 전환할 정도는 아니었다는 것을 들 수 있다. 이에 본 연구에서는 교통수단선택 계층에 따라 교통수요관리 방안에 대한 인식의 차이가 있을 것으로 보고, 불특정 다수의 통행에서 승용차의 이용빈도를 기준으로 교통수단선택 계층(승용차 의존층, 승용차 선택층, 대중교통 선택층, 대중교통 의존층)을 분류하고 각 계층별로 수단선택 영향요인에 대한 인식 및 교통환경의 변화에 대한 통행행태의 차이를 비교 분석하였다. 그 결과로 승용차의 의존도가 높을수록 편리함이나 쾌적함과 같은 정성적 요인을 더 중요시 인식하고 있으며, 주차규제나 통행시간 및 비용의 증가와 같은 교통수요관리기법에 대해서는 승용차의 의존도가 낮을수록 대중교통으로 전환될 가능성이 높다는 것을 나타내었다. 또한 주차규제 정책 추진시 주변 도로의 주차단속이 병행되어야 하며, 경제적인 부담을 가중시키는 방법으로는 주차요금과 같이 승용차 이용시 선택적으로 발생되는 비용보다 연료비 인상과 같이 상시적인 비용부담이 가중될 수 있는 방법이 보다 효과적이라는 정책적인 시사점을 제시하였다.