• Title/Summary/Keyword: Analysis of Kinematic

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Development of Body-Weight-Support System for Walking Rehabilitation (보행 재활을 위한 신체 자중 보상용 모바일 로봇에 관한 연구)

  • Suh, Seung-Whan;Yu, Seung-Nam;Lee, Sang-Ho;Han, Chang-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.10
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    • pp.3658-3665
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    • 2010
  • As the population of elderly people and disabled people are increased, various demands for human welfare using robot system are raised. Especially autonomous rehabilitation system using robot could reduce the human effort while maintaining the its intrinsic efficacy. This study deals with mobile gait rehabilitation system which combined with BWS (Body Weight Support) for training of elderly and handicapped people who suffer the muscle force weakness of lower extremity. BWS which is designed by kinematic analysis of body lifting characteristics and walking guide system are integrated with main control system and wheeled platform. This mobile platform is operated by UCS (User Command System) and autonomous trajectory planning algorithm. Finally, through the EMG (Electromyography) signal measuring and its analysis for subject, performance and feasibility of developed system is verified.

Judo-doll System Development for Enhancement of Judo's Performance (유도 경기력 향상을 위한 유도 인형시스템 개발)

  • Park, Kang;Shim, Cheol-Dong;Kim, Eui-Hwan;Kim, Sung-Sup;Kim, Tae-Whan
    • Korean Journal of Computational Design and Engineering
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    • v.15 no.5
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    • pp.383-392
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    • 2010
  • The purpose of this study is to develop three Judo-doll systems for enhancement of Judo's performance. Traditional Judo training requires a human training partner. Unfortunately it is not always easy to find one. Multifunctional Judo-doll training system has therefore been developed, and is described here. The system consists of a dummy, a power generating mechanism, and kinematic links. The power-generating mechanism generates forces similar to those of a human, by adjusting deadweights and controlling powderbrake's forces. The powderbrake force is controlled by the microprocessor according to the exercise scenario. The kinetic links, which mimic a human training partner's motions, has been developed based on a $Vicon^{TM}$ system's analysis of the movement of human training partners. This mechanism whose name is "L link-wire" consists of L type links, wire, roller, and dead weight. This mechanism generates the force that leads the link to the neutral position regardless the link is pushed or pulled. The lifting mechanism that lifts the doll when the one-armed shoulder throw skill is applied is also developed. A 32-bit microprocessor controls the whole system; it reads the loadcell data, controls the electromagnetic force, and communicates with a PC via Bluetooth. The training history, including loadcell data, date, and training time, is stored in the PC for analysis. This training system can be used to enhance the Judo performance of any self training player.

An Inverse Dynamic Model of Upper Limbs during Manual Wheelchair Propulsion (수동 휠체어 추진 중 상지 역동역학 모델)

  • Song, S.J.
    • Journal of rehabilitation welfare engineering & assistive technology
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    • v.7 no.1
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    • pp.21-27
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    • 2013
  • Manual wheelchair propulsion can lead to pain and injuries of users due to mechanical inefficiency of wheelchair propulsion motion. The kinetic analysis of the upper limbs during manual wheelchair propulsion needs to be studied. A two dimensional inverse dynamic model of upper limbs was developed to compute the joint torque during manual wheelchair propulsion. The model was composed of three segments corresponding to upper arm, lower arm and hand. These segments connected in series by revolute joints constitute open chain mechanism in sagittal plane. The inverse dynamic method is based on Newton-Euler formalism. The model was applied to data collected in experiments. Kinematic data of upper limbs during wheelchair propulsion were obtained from three dimensional trajectories of markers collected by a motion capture system. Kinetic data as external forces applied on the hand were obtained from a dynamometer. The joint rotation angles and joint torques were computed using the inverse dynamic model. The developed model is for upper limbs biomechanics and can easily be extended to three dimensional dynamic model.

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A Potential-Based Panel Method for the Analysis of a 2-Dimensional Partially Cavitating Hydrofoil (양력판 이론에 의한 2차원 수중익의 부분 캐비티 문제 해석)

  • Chang-Sup,Lee
    • Bulletin of the Society of Naval Architects of Korea
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    • v.26 no.4
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    • pp.27-34
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    • 1989
  • A potential-based panel method is formulated for the analysis of a partially cavitating 2-dimensional hydrofoil. The method employs dipoles and sources distributed on the foil surface to represent the lifting and cavity problems, respectively. The kinematic boundry condition on the wetted portion of the foil surface is satisfied by requiring that the total potential vanish in the inner flow region of the foil. The dynamic boundary condition on the cavity surface is satisfied by requiring that the potential vary linearly, i.e., the velocity be constant. Green's theorem then results in a potential-based boundary value problem rather than a usual velocity-based formulation. With the singularities distributed on the exact hydrofoil surface, the pressure distributions are predicted with more improved accuracy than the zero-thickness hydrofoil theory, especially near the leading edge. The theory then predicts the cavity shape and cavitation number for an assumed cavity length. To improve the accuracy, the sources and dipoles on the cavity surface are moved to the newly computed cavity surface, where the boundary conditions are satisfied again. It was found that five iterations are necessary to obtain converged values, while only two iterations are sufficient for engineering purpose.

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Numerical Verification for Plane Failure of Rock Slopes Using Implicit Joint-Continuum Model (내재적 절리-연속체 모델을 이용한 암반사면 평면파괴의 수치해석적 검증)

  • Shin, Hosung
    • Journal of the Korean Geotechnical Society
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    • v.36 no.12
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    • pp.125-132
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    • 2020
  • Embedded joints in the rock mass are a major constituent influencing its mechanical behavior. Numerical analysis requires a rigorous modeling methodology for the rock mass with detailed information regarding joint properties, orientation, spacing, and persistence. This paper provides a mechanical model for a jointed rock mass based on the implicit joint-continuum approach. Stiffness tensors for rock mass are evaluated for an assemblage of intact rock separated by sets of joint planes. It is a linear summation of compliance of each joint sets and intact rock in the serial stiffness system. In the application example, kinematic analysis for a planar failure of rock slope is comparable with empirical daylight envelope and its lateral limits. Since the developed implicit joint-continuity model is formulated on a continuum basis, it will be a major tool for the numerical simulations adopting published plenteous thermal-hydro-chemical experimental results.

HP-GPC Analysis for Characteristics Change of Asphalt Cement Due to Aging (노화(老化)에 의한 아스팔트 시멘트 형질변화(形質變化)의 HP-GPC 분석(分析))

  • Kim, Kwang Woo;Yeon, Kyu Seok;Choi, Joong Dae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.12 no.4
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    • pp.49-57
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    • 1992
  • This study was conducted to evaluate physical property change of asphalt cement chromatograms (by HP-GPC) were experimentally obtained from 3 types of AC-20 virgin ACs, 5 and 24-hour artificially aged ACs, and naturally aged 4 ACs that were recovered from 4 different roads. Absolute viscosity, kinematic visoosity and penetration were the physical properties tested. THF was used for mobil phase and RI detector was used as a detector for Hp-GPC testing. Correlation between each physical property change and the chromatogram variation was evaluated. Each chromatogram was divided into ten-equal-time slices. The percentage areas of 10 slices and each physical property were used for statistical correlation evaluation. Statistical analysis results showed that eaoh physical property had a strong correlation with the chromatogram characteristics. Aging was identified as a mechanism of change of molecular size distribution - increasing large size molecules and reducing coresponding samll size molecules.

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Analysis of Relationship between Biomechanical Factors and Driver's Distance during Golf Driver Swing (골프 드라이버 스윙 시 운동역학 요인들과 비거리 관련성 분석)

  • Lim, Young-Tae;Park, Jun-Sung;Lee, Jae-Woo;Kwon, Moon-Seok
    • Journal of the Korean Applied Science and Technology
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    • v.38 no.1
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    • pp.1-8
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    • 2021
  • The purpose of this study was to analyze relationship between biomechancal factors and diver's distance during golf driver swing. Fifteen professional golfers were participated in as subject. Eight motion capture cameras(250 Hz), 2 force plates(1000 Hz), and Trackman were used to collect kinematic and kinetic datas. It was performed Pearson's correlation analysis using SPSS 24.0. The level of significance was at .05. Ball speed, club head speed, X-Factor, and ground reaction force were correlated on driving distance, However, smash factor and knee moment were not correlated on driving distnace. Ball speed, club head speed, X-Factor, and ground reaction force were effected to driving distance, but smash factor and knee moment were not effected to driving distance.

Hypervelocity Impact Analysis Of Composite Plate For Space Shielding System (우주용 쉴딩 시스템에 적용할 복합재료 평판의 초고속 충돌 해석)

  • Son, Yu-Na;Moon, Jin-Bum;Lim, Gun;Kim, Chun-Gon
    • Composites Research
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    • v.23 no.6
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    • pp.14-18
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    • 2010
  • Among the factors that threaten spacecraft, Micrometeoroid and Orbital Space Debris(MMOD) cause damage to spacecraft and impact velocity is about 8~70km/s. Nowadays, various Whipple Shield are studied and applied to protect spacecraft. As the materials used to Shielding System, aluminum is usually used but composite is also used increasingly. So this study compared characteristics of hypervelocity impact of Aluminum and composites through finite element analysis. The Projectile was a spherical shape using Aluminum 2017-T4, and aluminum plate was using Aluminum 6061-T6, CFRP plate was using T300/5208. Initial impact velocity of projectile was 1km/s. As a result, kinematic energy of projectile decreased to about 64J and about 63J for aluminum plate and CFRP plate, respectively after impact. Although both results is almost same about the absorption of impact energy, you can think the CFRP has good ballistic characteristic, because CFRP is lighter about 1.7 times compared with density of aluminum.

Analysis of Spatio-Temporal Parameters of Gait in Elderly by Various Walking Pathways Width (보행경로 너비에 따른 노인의 시 · 공간적 보행 분석)

  • Son, Ho-Hee;Kim, Eun-Jung
    • The Journal of the Korea Contents Association
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    • v.13 no.10
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    • pp.444-451
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    • 2013
  • The purpose of this study was to investigate the changes in temporospatial variables in healthy elderly and healthy adults during usual walking, narrow base walking and centerline-guided walking. Twenty healthy elderly and nineteen healthy adults were participated in this study. In each conditions, the subjects were walked on a 6m walkway at comfortable self-selected speeds under three conditions : (1) usual walking, (2) walking within a 50% of the distance between the subject's ASIS (3) walking along a centerline. GAITRite system was used for kinematic analysis to assess the temporospatial variables. There were no significant changes in healthy adults(p>.05), but walking speed, cadence, H-H base support, functional ambulation performance were significantly decreased progressively as pathway narrowed in elderly adults(p<.05). The results show that elderly people had more difficulty with walking on narrow pathway for fear of falling. This study provides data for use in basic research into safe walking and preventing falling for elderly.

Kinematic Analysis of a Scoop Motion in Elite Male Hockey Players (남자 우수하키 선수들의 스쿱 동작에 관한 운동학적 분석)

  • Lim, Jung-Woo
    • Korean Journal of Applied Biomechanics
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    • v.19 no.3
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    • pp.481-488
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    • 2009
  • The purpose of this study was to investigate the hokey scoop motion of elite male hockey players. To accomplish the goal of this study, eight male hockey players participated and were divided into two groups (superior group Vs. inferior group). To find differences between groups, a three-dimensional motion analysis was performed with seven infrared cameras (SF: 200Hz). After analyzed their scoop motion, followings were found. 1) The non-significant(p>.05) increase in anterior CG displacement and velocities were found in superior group compare with inferior group) 2) There were no significance found in anterior-posterior stick velocities between groups. However, significant (p<.05) increase in vertical stick velocities were found in superior group than inferior group indicating the superior group has more skilled in scooping. 3) The significant(p<.05) increase in adductional and internal rotational stick released velocities were found in superior group than inferior group.