• 제목/요약/키워드: slippery

검색결과 140건 처리시간 0.025초

우천 시 서울메트로 신형 VVVF 전동차(2,3호선)의 슬립현상에 관한 연구 (A Study on SLIP actual condition of rainy day at the time of Seoul Metro new style VVVF Inverter Rolling Stock (2,3 lines))

  • 김재현;김주태;남재호;손영진
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2010년도 춘계학술대회 논문집
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    • pp.1371-1375
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    • 2010
  • Recently, the Seoul Metro has replaced the old series of Line No.2 and 3 to the new ones. In spite of the replacement, the new ones are more likely to be slippery compared to the old ones. Because the subway system has such short intervals, delayed subways influence the whole line systems, especially during the rush hours. And the slip causes the delay. Therefore we are willing to find out the reason why the new ones are more defective and we will try to mince it from the view of mechanical aspects and handling aspects of driving.

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대전시 거주 노인의 욕실 및 통로공간 디자인에 대한 중요도 평가 (Bathroom and approach design details evaluated by the elderly in Daejeon city)

  • 이지숙;박정아
    • 한국실내디자인학회논문집
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    • 제41호
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    • pp.121-128
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    • 2003
  • This study was purposed to find that the elderly in Daejeon city evaluated design details in bathroom, stairway, entrance etc. On the base of housing expenses and an administrative district, the elderly over 65 were chosen and interviewed by well-trained investigators and 583 case was analyzed through SPSS PC 10.0. The results of this study were as follows ; they said a bathtub was necessary, the floor was not slippery, the height of basin was not high and the grab bar around toilet was not in bathroom and emergency bell was not in house. The elderly pointed out that the non-slip floor, grab bar, bathtub in bathroom and non-slip floor in entrance and stairs should be designed carefully. By the condition of the elderly' health and independent daily living and experience of housing, the evaluation of importance on bathroom and approach design by the elderly were different.

차량의 선회시 주행 안정성 강화를 위한 ESP 시스템 개발 및 성능 평가 (II) (Development and Evaluation of ESP Systems for Enhancement of Vehicle Stability during Cornering (II))

  • 송정훈
    • 대한기계학회논문집A
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    • 제30권12호
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    • pp.1551-1556
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    • 2006
  • Two yaw motion control systems that improve a vehicle lateral stability are proposed in this study: a rear wheel steering yaw motion controller (SESP) and an enhanced rear wheel steering yaw motion controller (ESESP). A SESP controls the rear wheels, while an ESESP steers the rear wheels and front outer wheel to allow the yaw rate to track the reference yaw rate. A 15 degree-of-freedom vehicle model, simplified steering system model, and driver model are used to evaluate the proposed SESP and ESESP. A robust anti-lock braking system (ABS) controller is also designed and developed. The performance of the SESP and ESESP are evaluated under various road conditions and driving inputs. They reduce the slip angle when braking and steering inputs are applied simultaneously, thereby increasing the controllability and stability of the vehicle on slippery roads.

Tractor-Semitrailer 차량의 제동특성 프로그램 개발 (A Simulation Program for the Braking Characteristics of Tractor-Semitrailer Vehicle)

  • 서명원;박윤기;권성진;양승환;박병철
    • 한국자동차공학회논문집
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    • 제9권2호
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    • pp.152-167
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    • 2001
  • Recently safety systems for the commercial vehicle have been rapidly developed. However, we still have many problems in the vehicle stability and the braking performance. Especially, a commercial vehicle may meet a dangerous braking condition when the vehicle is lightly loaded or empty and when the road is wet or slippery. Under these conditions, the truck can spin out or the tractor can jackknife or the trailer can swing out. To design the air brake system for the commercial vehicle, since the air brake system has many design variables, there must have been intensive researches on a method how to prevent dynamic instability and how to maximize the vehicle deceleration. In this study, mathematical models about the tractor-semitrailer and the air brake system including an ABS controller have been constructed for computer simulation. Also, simple examples are applied to show the usefulness of the program. Designers can use this simulation program for understanding the braking characteristics such as trajectory, braking distance, longitudinal deceleration, lateral deceleration, and yaw rate on various road conditions.

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차량 안정성 향상을 위한 제어기 설계 (Design of Control Logics for Improving Vehicle Dynamic Stability)

  • 허승진;박기홍;이경수;나혁민;백인호
    • 한국자동차공학회논문집
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    • 제8권5호
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    • pp.165-172
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    • 2000
  • The VDC(Vehicle Dynamic Control) is a control system whose target is to improve stability of a vehicle under lateral motion. A lateral vehicle motion, especially on a slippery road, can lead to a hazardous situation, and the situation can even worsen by the driver`s inappropriate response. In this paper, two VDC systems, a fuzzy-based controller and an LQR-based controller have been developed. The controllers take as input the yaw rate and the sideslip angle of either body or rear wheel, and they yield the direct yaw moment signal by which the vehicle can gain stability during cornering. Simulations have been conducted to evaluate the performance of the control system. The results indicated that the controllers can successfully improve vehicle stability under potentially dangerous driving conditions.

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폭이 좁은 차량의 비상주행시 주행성능개선을 위한 제어시스템에 관한 연구 (A Study on the Control System of the Narrow Vehicles for Improvement of Maneuvering under Emergency Situation)

  • 소상균
    • 한국자동차공학회논문집
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    • 제12권6호
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    • pp.166-174
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    • 2004
  • In urban area narrow commuter vehicles have attracted interest as a possible solution to reduce traffic congestion and parking problems. However, a narrow vehicle has an increased to overturn during hard cornering when compared to conventional vehicles. This tendency can be reduced by tilting it toward the inside of the turn. Two types of automatic tilting control systems which are Direct Tilt Control(DTC) and Steering Tilt Control(STC) have been developed. In this paper as one of the technique to improve the handling performance for the unusual vehicle the control system which blends both the DTC and the STC system is considered. It uses the merits of both the DTC and the STC system. As a control strategy for combination the switching control method is used. Finally, the fact that the unusual vehicle is safe under an emergency situation such as slippery road surface is proved by computer simulation.

전도 측정을 위한 모바일 로봇 플랫폼 구현 (Mobile robot platform embodiment to measure slippery degree of road)

  • 이동광;공정식;권오상;장문석;강신혁;신운철;김정수;이응혁
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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    • pp.83-84
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    • 2007
  • 작업자가 작업장에서 전도 등으로 인한 산업 재해를 입지 않도록 하기 위해서는 작업장에서의 전도 상황을 판단하여야 하며, 이러한 전도 상황을 측정할 때 자동화된 전도 측정 장치는 작업장에서의 효율성을 확보하는 동시에, 전도를 측정하는 사람이 측정 과정예서 일어날 수 있는 불상사 등을 예방하여 산업재해를 미연에 방지해서 이를 통한 산업 현장의 안정성 확보를 통한 부대 비용 발생을 방지할 수 있게 된다. 이러한 자동화된 전도 측정을 위한 방편으로써 전도 측정용 로봇의 개발하였다.

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노인주거시설 단위주호의 욕실 계획 실태 (A Status of Bathroom Planning of Units in Elderly Housing Facilities)

  • 주서령;이지예
    • 한국실내디자인학회논문집
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    • 제14권4호
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    • pp.45-53
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    • 2005
  • Compared with a lot of comprehensive and alternative studies on elderly housing facilities until now, specialized studies of dimensional and detailed standards have hardly made. Therefore we intends to examine the status of bathroom planning on representative elderly housing facilities in Korea. As the methods of this study, we executed a field study into five representative elderly housing facilities in Korea. We visited each two units out of the outstanding 5 facilities and surveyed the total ten bathrooms. Then we analyzed the space planning of them and the state of bathroom commodities, and measured the bathroom equipment. In addition, we collected questionnaires about satisfaction, preference, and problems from the residents. As a result, most of the bathrooms had powder rooms and were furnished with bathtubs(4) and shower stalls(6). One or more grab bar and emergency calling system were provided but the heights of the handles were different from each bathroom. The floor material of bathroom should be installed with no-slippery material.

High level of estradiol in a Holstein-Friesian cow with sacroiliac luxation after calving

  • Mamuad, Lovelia L.;Seo, Bosung;Kang, Seogjin;Cho, Yong-Il
    • 대한수의학회지
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    • 제60권4호
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    • pp.237-240
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    • 2020
  • This is the report of sacroiliac luxation in a Holstein-Friesian cow, describing the progression of the sacroiliac luxation from the onset of its development with changes in estradiol (E2) and serum chemistry. The high estrogen concentration was assumed to be a predisposing factor of the disease that relaxed the pelvic muscles and a secondary slippery finally caused the sacroiliac luxation. The E2 was present at levels four times higher in the cow with sacroiliac luxation (167 pg/mL) than in normal cows. Above normal levels of creatinine kinase, aspartate aminotransferase, and lactate dehydrogenase were also observed in cow with sacroiliac luxation.

전륜 제동력 및 전륜 조향각을 이용한 SUV 차량의 통합운동제어시스템 개발 (Integrated Dynamics Control System for SUV with Front Brake Force and Front Steering Angle)

  • 송정훈
    • 한국기계가공학회지
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    • 제21권5호
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    • pp.22-27
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    • 2022
  • An integrated front steering system and front brake system (FSFB) is developed to improve the stability and controllability of an SUV. The FSFB simultaneously controls the additional steering angle and front brake pressure. An active front steering system (AFS) and an active front brake system (AFB) are designed for comparison. The results show that the FSFB enhances the lateral stability and controllability regardless of road and running conditions compared to the AFS and AFB. As a result, the yaw rate of the SUV tracks the reference yaw rate, and the side slip angle decreases. In addition, brake pressure control is more effective than steering angle control in improving the stability and steerability of the SUV on a slippery road. However, this deteriorates comfort on dry or wet asphalt.