• 한국자동차공학회논문집
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• 제14권1호
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• pp.167-175
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• 2006

Directional stability is important performance in vehicle and tire design. The current methods to analyze this is generally based on linear concept. Using the existing concept, it cannot realistically explain the subjective assessment at all because it is hard to practically represent the nonlinear behaviour of a complex vehicle system in reality. In this paper, new method to analyze directional stability is introduced. At first, directional stability of vehicle is categorized into yaw, rear axle, and roll stability. In order to objectify these items, driver perceptual parameters based on subjective assessment are used. Using the perceptual parameters, it can successfully explain the transient maneuver of vehicle and extract objective parameters for directional stability. Finally, these objective parameters are successfully validated through two handling tests, lane change and severe lane change. The correlation results show that there exists a good correlation between subjective assessment and the proposed objective parameters.

• 한국ITS학회 논문지
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• 제14권3호
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• pp.9-23
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• 2015

차로변경은 운전자의 숙련된 주변인식 및 운전기술이 요구되어 심각한 교통사고를 야기한다. 그리하여 우리는 불가피한 차로변경이 대두되는 고속도로 합류구간에서 본선으로 합류하는 차량의 차로변경을 보조하는 차량 자동제어 시스템 (ALCAS; Advanced Lane Change Assist System)을 개발한다. 본 연구에서는 ALCAS 중 조향이 수행되기 이전에 최적 차로변경 시작지점(Optimal Lane Change Start Point; OLCSP)을 생성하고 그 지점까지 도달하는 종방향 제어 알고리즘 개발에 초점을 두었다. 이를 위해 우선 고속도로 합류구간의 차로변경 행태를 분석하였고, 실제 차량의 가속도 함수 형태를 통해 차로변경 특징모형(Lane Change Feature Model)을 설계하였다. 그 후 차로변경 수행 단계를 정립하였으며, 이 알고리즘 성능과 타당성을 검증하기 위하여 다양한 주변차량 주행환경에 따른 시나리오 시험을 수행하였다. 또한 개발된 알고리즘의 효과를 미시적 교통류 시뮬레이션 (VISSIM)을 통해 확인하였다. 개발한 알고리즘을 합류차량에 적용한 결과 안정류 상태에서 합류성능이 두드러지게 개선되는 것을 확인하였다. 이 차량 자동제어 시스템은 교통 자동차 분야 융합기술의 일환으로 개발되었으며, 운전자의 부하와 오류를 감소시켜 효율성과 안전성을 향상시킬 뿐만 아니라 교통류의 안정성, 임계용량, 주행 효율성의 증대로 사회비용 감소를 기대할 수 있다.

• International Journal of Automotive Technology
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• 제6권6호
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• pp.615-623
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• 2005

In this research, an effective technique was examined to improve the drift running performance. Concretely, the driver model by which the counter steer was done was assumed to the model by which the vehicle body slip angle (and the vehicle body slip angle velocity) was feed back. Next, the effectiveness of the system which added the assist steer angle corresponding to the steering wheel angle velocity to a front wheel steer angle was clarified as a drift running performance improvement technique of the vehicle. As a result, because the phase advances when the differentiation steer assistance is added, it has been understood to be able to cover the delay of the counter steer when the drift running. Therefore, it has been understood that the drift control does considerably easily. Moreover, it has been understood that the differentiation steer assistance acts effectively at the drift cornering by which the drift angle is maintained in cornering and the severe lane change with a drift at a situation. That is, it was understood to be able to settle to the drift angle of the aim quickly at the time of the drift cornering because the delay of the control steer angle of the counter steer was improved. Moreover, it was understood for the transient overshoot of the vehicle tracks to be able to decrease, and to return to the state of stability quickly at the severe lane change.

• Geomechanics and Engineering
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• 제22권5호
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• pp.449-460
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• 2020

The double-lane arrangement model is frequently used in underground coal mines because it is beneficial to improve the mining efficiency of the working face. When the double-lane arrangement is used, the service time of the reserved roadway increases by twice, which causes several difficulties for the maintenance of the roadway. Given the severe non-uniform deformation of the reserved roadway in the Buertai Coal Mine, the stress distribution law in the mining area, the failure characteristics of roadway and the control effect of support resistance (SR) were systematically studied through on-site monitoring, FLAC 3D numerical simulation, mechanical model analysis. The research shows that the deformation and failure of the reserved roadway mainly manifested as asymmetrical roof sag and floor heave in the region behind the working face, and the roof dripping phenomenon occurred in the severe roof sag area. After the coal is mined out, the stress adjustment around goaf will happen to some extent. For example, the magnitude, direction, and confining pressure ratio of the principal stress at different positions will change. Under the influence of high-stress rotation, the plastic zone of the weak surrounding rock is expanded asymmetrically, which finally leads to the asymmetric failure of roadway. The existing roadway support has a limited effect on the control of the stress field and plastic zone, i.e., the anchor cable reinforcement cannot fully control the roadway deformation under given conditions. Based on obtained results, using roadway grouting and advanced hydraulic support during the secondary mining of the panel 22205 is proposed to ensure roadway safety. This study provides a reference for the stability control of roadway with similar geological conditions.