• 제목/요약/키워드: Ramp height

검색결과 40건 처리시간 0.031초

경사로의 기울기와 높이에 따른 휠체어 사용자의 사용성 및 생리적 특성 분석 (Effects of Ramp Slope and Height on Usability and Physiology during Wheelchair Driving)

  • 김충식;이동훈;이지혜;권성혁;정민근
    • 대한인간공학회지
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    • 제29권4호
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    • pp.681-686
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    • 2010
  • Although the height of a ramp is an important design element, it has not been considered in prior studies. Therefore, in this study, the ramp slope and height are considered as independent variables. To analyze the effects of the slope and height, five levels of slope (1:6, 1:8, 1:10, 1:12 and 1:14) and three levels of height (15cm, 30cm and 45cm) are considered. For the dependent variables, the total time, velocity and perceived discomfort were considered as usability measures, pulse rate changes and EMG signals of four related muscles (extensor carpi radialis, triceps brachii, anterior deltoid and posterior deltoid) were considered as physiology measures. As a result, differences among usability and physiological characteristic for the five slopes increased as the height increased. Additionally, slope effects were minor when the height was low (15cm). Almost domestic/international regulations and guidelines related to ramp recommended 1:12 slope for the ramp design, however, there was no significant difference between 1:10 and 1:12 according to result of this study. In addition, slope effects were minor at a low height; thus, a slope of 1:8 can be recommended if the installation space for a gentler ramp is not sufficient.

Experimental Study on a Rectangular Variable Intake for Space Planes

  • Kojima, T.;Taguchi, H.;Okai, K.;Futamura, H.;Maru, Y.
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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    • pp.649-656
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    • 2004
  • Hypersonic wind tunnel test of the rectangular variable geometry intake is performed. For realization of a Precooled turbojet engine, development of a hypersonic ramjet engine is planned. To investigate performance of the intake of the hypersonic ramjet engine, wind tunnel test is done with freestream Mach number of 5.1. The total pressure recovery was 18 % with 12.9 % of ramp bleed. Several reasons for low total pressure recovery are shown. Supersonic internal compression is not enough. Then, the throat Mach number is high (M2.61) and total pressure losses at the terminal shock is large. Supersonic flow at the throat and position of the terminal shock is sensitive to a difference of the second ramp's throat height and the third ramp's throat height. Flow separations at the second ramp's trailing edge and the third ramp's leading edge are seen those could result in the trigger of unstart. The seal mechanism between the ramps and the sidewalls is important.

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초소형 하드디스크에서 램프 형상 분석 및 설계 프로세스 연구 (Design Procedure and Analysis of Ramp Profile in SFF HDD)

  • 이용현;박경수;박노철;양현석;박영필
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2006년도 춘계학술대회논문집
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    • pp.384-387
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    • 2006
  • Vertical L/UL (Load/Unload) velocity is very important parameter to determine the L/UL performance, and the vertical velocity is determined by the actuator velocity and the ramp profile. However, it is not easy to precisely control the actuator rotating velocity during the L/UL process. Especially in emergency parking, servo system doesn't operate, it is impossible to control an actuator velocity. Then, the vertical unloading velocity depends on only ramp profile. The ramp height and the sliding length for L/UL process in SFF (Small Form Factor) HDD are restricted due to slimness and small media. For these reasons, it is very difficult to design the ramp profile in SFF HDD. Therefore, this study analyzes the unloading dynamic characteristics for various ramp profiles and makes the thesis for ramp profile design.

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초소형 하드디스크에서 램프 형상 분석 및 설계 프로세스 연구 (Design Procedure and Analysis of Ramp Profile in SFF HDD)

  • 이용현;박경수;박노철;양현석;박영필
    • 정보저장시스템학회논문집
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    • 제2권2호
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    • pp.150-155
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    • 2006
  • Vertical L/UL (Load/Unload) velocity is very important parameter to determine the L/UL performance, and the vertical velocity is determined by the actuator velocity and the ramp profile. However, it is not easy to precisely control the actuator rotating velocity during the L/UL process. Especially in emergency parking, servo system doesn't operate, it is impossible to control an actuator velocity. Then, the vertical unloading velocity depends on only ramp profile. The ramp height and the sliding length for L/UL process in SFF (Small Form Factor) HDD are restricted due to slimness and small media. For these reasons, it is very difficult to design the ramp profile in SFF HDD. Therefore, this study analyzes the unloading dynamic characteristics for various ramp profiles and makes the thesis for ramp profile design.

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교통약자를 위한 소형버스의 탑승구 디자인 (A Study on the Ramp Design of Small Buses for the Mobility Handicapped)

  • 이정현;김인철
    • 한국생산제조학회지
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    • 제21권2호
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    • pp.214-220
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    • 2012
  • About 12 million people of the mobility handicapped were increased by the end of 2009 year. Universal design concept has been implemented in developed countries. Since 2004 low-floor buses are in Korea. In this study, there is no provision for mobility handicapped and small buses that can be comfortable riding car ramp design presented. The gate of a small buses lowered height of 200mm. Install the ramp in the center of the ramp by an air cylinder moves from side to side. The slope of the ramp was controlled by a hinge. Air cylinder thin type applicable in the narrow space of the slide cylinder was used.

균일 및 난류 입구조건이 램프 후류 형상 및 성장에 미치는 영향 (Effects of Uniform and Turbulent Inflow Conditions on Wake Topology and Vortex Growth Behind a Ramp)

  • 구티 로키시 카리안;요시프 무스타파;임희창
    • 한국가시화정보학회지
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    • 제21권2호
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    • pp.24-33
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    • 2023
  • This work is to observe the wake flow generated behind a ramp. We have conducted a large eddy simulation with two ramp models having different heights with two different inflow conditions. Reynolds number based on the height of the large ramp (LR) and small ramp (SR) are Reh = 2.8×104 and 1.4×104 respectively. The wake flow visualization shows the formation of streamwise counter-rotating vortices pairs at the downstream of the obstacle. These primary vortices are stretched and lifted up when moving downstream. In order to observe the effect of the inflow condition on the wake transition, two different inlet flow conditions are given on the inlet section as an inlet boundary condition. Induced counter-rotating vortices pairs due to sharp-edged triangular ramp obstacles are developed and propagated downstream. In the result, the large ramp shows a more complicated wake structure of the boundary layer than the small ramp.

보행로 형태가 여성노인들의 하지관절에 미치는 영향 (The Effects of Age and Walkway Type on Lower Extremities Kinematics in Elderly Women)

  • 우병훈;박양선
    • 한국운동역학회지
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    • 제25권3호
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    • pp.249-256
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    • 2015
  • Objective : The purposes of this study was to perform a kinematical analysis on age and walkway types in elderly women subjects. Method : Forty subjects participated in the experiment (A1 group - age: $67.30{\pm}1.49yrs$, height: $153.81{\pm}4.47cm$, weight: $61.80{\pm}5.24kg$, A2 group - age: $71.70{\pm}1.10yrs$, height: $152.01{\pm}2.84cm$, weight: $59.69{\pm}7.34kg$, A3 group - age: $76.80{\pm}0.98yrs$, height: $150.16{\pm}6.08cm$, weight: $57.27{\pm}6.42kg$, A4 group - age: $81.80{\pm}0.60yrs$, height: $152.18{\pm}4.77cm$, weight: $55.80{\pm}7.78kg$). The study method adopted was the 3D analysis with six cameras. Ground type were classifed as gait pattern on flat, ascent and descent ramp. For the statistical analysis, the SPSS 21.0 was used to perform Repeated measured Two-way ANOVA. Results : In velocity of CM, there was faster movement on flat ground. When it came to the velocity of right toe, there was no significance in early mid-swing of right foot, but A4 was the slowest in late mid-swing of right foot on flat ground. In joint angle in left foot strike, the left hip joint and knee joint were more flexed in descent ramp, In addition left and right ankle joints were more plantarflexed in descent ramp, and left ankle joint was more plantarflexed in the over 75 yrs age groups. Conclusion : The higher age group were more flexed in lower body joints during descent ramp.

REDUCTION OF HIGH FREQUENCY EXCITATIONS IN A CAM PROFILE BY USING MODIFIED SMOOTHING SPLINE CURVES

  • Kim, D.J.;Nguyen, V.T.
    • International Journal of Automotive Technology
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    • 제8권1호
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    • pp.59-66
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    • 2007
  • High frequency excitation terms in a cam profile can excite vibration of a cam follower system. In this paper, modified smoothing spline curves are used to reduce the high frequency terms. The essential difference between the proposed method and other existing approaches is its ability to make the principal cam motions smooth while still exactly satisfying boundary conditions of follower displacement, velocity and acceleration. The boundary values usually depend on the ramp properties of a cam. Our method, thus, allows designers to smooth the existing cam motion without any damages on its ramp areas. Because the ramp height, velocity and acceleration are maintained exactly, more radical smoothing is possible. An example shows that the proposed method can be a powerful tool of cam profile smoothing, which removes high frequency components in the cam profile excitations without any changes in ramp properties.

The Effects of Ramp Gradients and Pushing-Pulling Techniques on Lumbar Spinal Load in Healthy Workers

  • Pinupong, Chalearmpong;Jalayondeja, Wattana;Mekhora, Keerin;Bhuanantanondh, Petcharatana;Jalayondeja, Chutima
    • Safety and Health at Work
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    • 제11권3호
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    • pp.307-313
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    • 2020
  • Background: Many tasks in industrial and health care setting are involved with pushing and pulling tasks up or down on a ramp. An efficient method of moving cart which reduces the risk of low back pain should be concerned. This study aimed to investigate the effects of handling types (HTs) and slope on lumbar spinal load during moving a cart on a ramp. We conducted a 2 × 2 × 4 factorial design with three main factors: 2 HTs, 2 handling directions of moving a cart and 4 degrees of ramp slope. Methods: Thirty healthy male workers performed 14 tasks consist of moving a cart up and down on the ramp of 0°, 10°, 15°, and 20° degrees with pushing and pulling methods. Joint angles from a 3D motion capture system combined with subject height, body weight, and hand forces were used to calculate the spinal load by the 3DSSPP program. Results: Our results showed significant effect of HT, handling directions and slope on compression and shear force of the lumbar spine (p < 0.001). When the ramp gradient increased, the L4/5 compression forces increased in both pushing and pulling (p < 0.001) Shear forces increased in pulling and decreased in pushing in all tasks. At high slopes, pulling generated more compression and shear forces than that of pushing (p < 0.01). Conclusion: Using the appropriate technique of moving a cart on the ramp can reduce the risk of high spinal load, and the pushing is therefore recommended for moving a cart up/down on ramp gradients.

지체장애인의 관점에서 본 소규모 아파트 공간에서의 유니버설 디자인 특성 (Universal Design Characteristics in Small Apartment Housing Focusing on the Physically Disabled)

  • 오찬옥
    • 한국주거학회논문집
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    • 제11권3호
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    • pp.99-107
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    • 2000
  • The purpose of this study was to identify the universal design characteristics in residential environments. The subjects were 135 physically disabled persons who lived in the rental multi-family housing apartments in Pusan. Interview method was used for this study. They were an average age of 51 years and 63% were male. They were low income families and lived in 12 pyung ($39.75\textrm{m}^2$) apartments. They were asked about what housing characteristics were constraints in their daily living. They pointed out that the constraints in their apartments were as follows: 1) the small amount of space in the bathroom, kitchen, bedroom, and the entrance area of housing unit, 2) the unflat floor level between the bathroom and the hallway, or the balcony and the bedroom, 3) the slippery floor finish in the bathroom, 4) lack of grab bars or handrails in the bathroom and the ramp, 5) the kitchen work centers and the electric switches at improper height, and 6) the steep ramp. Therefore, the universal design characteristics in residential environments were the adequate amount of space, flat floor level, non-slippery floor finish, grab bars or handrails, accessible height, and ramp.

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