• 제목/요약/키워드: Kinematic parameters

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Gait analysis methods and walking pattern of hemiplegic patients after stroke (뇌졸중환자의 보행분석방법과 보행특성)

  • Han, Jin-Tae;Bae, Sung-Soo
    • PNF and Movement
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    • v.5 no.1
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    • pp.37-47
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    • 2007
  • Objective : A large proportion of stroke survivors have to deal with problems in gait. Proper evaluation of gait must be undertaken to understand the sensorimotor impairment underlying locomotor disorders post stroke. Methods : The characteristics of gait pattern with post stroke are reviewed in this paper. In particular, temporal distance parameters, kimematics, kinetics, as well as energy cost, EMG are focused. Results : The technology for gait analysis is moving rapidly. The techniques of 3D kinematic and kinetic analysis can provide a detailed biomechanical description of normal and pathological gait. This article reviews gait analysis method and characteristics of post stroke. Finally current method of gait analysis can provide further insight to understand paretic gait and therapeutic direction.

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An Investigation on Design of the Gear Reductioner for the Vibration Suppression (진동 저감을 위한 치차감속기 설계에 대한 연구)

  • 이형우;박노길
    • Journal of KSNVE
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    • v.5 no.2
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    • pp.183-195
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    • 1995
  • The mathematical model of the gear reductioner which consists which consists of the geared rotor-bearing system containing case is developed, assuming as the lumped parameter system. Constraints for vibration suppresion as well as strength of gear teeth, and shaft and kinematic conditions in gear pairs are considered. To find the design parameters satisfing the proposed constraints, a direct search method modified by the technique of Taguchi's experimental scheduling is used. One and two stepped gear reductioners are designed so that the criticl speeds due to the gear transmission error are moved out of the operating speed range.

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Development of Quantitative Diagnostic Technique for Low-Back Pain Patients via Three Dimensional Dynamic Motion Analysis (3차원 동작분석에 의한 요통환자의 정량적 진단기법 개발에 관한 연구)

  • Kim, Jeong-Ryong
    • Journal of the Ergonomics Society of Korea
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    • v.17 no.2
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    • pp.11-23
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    • 1998
  • Dynamic motion difference between normal subjects and low-back pain (LBP) patients has been investigated in terms of kinematic variables such as range of motion, velocity and acceleration of the back and hip. Ten healthy subjects and ten LBP patients were recruited in this study. Electro-goniometer such as Lumbar Motion Monitor and Hip Monitor have been used for quantitative measurement of the trunk motion during repetitive flexion and extension for ten seconds. Results indicated that the velocity and acceleration of the back and hip were important parameters to quantitatively identify LBP patients. The consistency of cyclic trunk motion and the relationship between the back and hip were measured in terms of Variance Ratio and Phase Angle in order to accurately assess the motion characteristics of LBP patients. In particular, the hip motion has been proven to be a very important factor in describing the kinematics of damaged lower back. The functional evaluation technique suggested in this study will be a tool to assist physicians for an accurate diagnosis and timely rehabilitation along with current image diagnosis techniques.

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Free vibration of functionally graded thin elliptic plates with various edge supports

  • Pradhan, K.K.;Chakraverty, S.
    • Structural Engineering and Mechanics
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    • v.53 no.2
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    • pp.337-354
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    • 2015
  • In this article, free vibration of functionally graded (FG) elliptic plates subjected to various classical boundary conditions has been investigated. Literature review reveals no study has been performed based on functionally graded elliptic plates till date. The mechanical kinematic relations are considered based on classical plate theory. Rayleigh-Ritz technique is used to obtain the generalized eigenvalue problem. The material properties of the FG plate are assumed to vary along thickness direction of the constituents according to power-law form. Trial functions denoting the displacement components are expressed in simple algebraic polynomial forms which can handle any edge support. The objective is to study the effect of geometric configurations and gradation of constituent volume fractions on the natural frequencies. New results for frequency parameters are incorporated after performing a test of convergence. A comparison study is carried out with existing literature for validation in special cases. Three-dimensional mode shapes for circular and elliptic FG plates are also presented with various boundary conditions at the edges.

The Optimum Design of a Spatial 3-DOF Manipulator Using Axiomatic Design (공리적 설계를 이용한 공간형 3자유도 기구의 최적설계)

  • Han Seog Young;Yi Byung-Ju;Kim Seon Jung;Kim Jong O;Chung Goo Bong
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.6
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    • pp.52-60
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    • 2005
  • Ultra-precision positioning systems basically require high natural frequency and sufficient workspace. To cope with this requirement, flexure hinge mechanisms have been developed. However, previous designs are difficult to satisfy the functional requirements of the system due to difficulty in modeling and optimization process applying fur the independent axiomatic design. Therefore, this paper suggests a new design and design procedure based on semi-coupled, axiomatic design. A spatial 3-DOF parallel type micro mechanism is chosen aa an exemplary device. Based on preliminary kinematic analysis and dynamic modeling of the system, an optimum design is conducted. To check the effectiveness of the optimal parameters obtained by theoretical approach, simulation has been performed by FEM.

A Study on Numerical Analysis of Wheel-rail Contact Points (차륜과 레일 접촉위치의 수치해석에 관한 연구)

  • Kang, Ju-Seok
    • Journal of the Korean Society for Railway
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    • v.12 no.2
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    • pp.236-242
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    • 2009
  • This paper presents a numerical analysis method to determine flange contact at variable wheel positions. The shapes of the wheel and rail surface functions with surface parameters. The Newton-Rhapson method for wheel-rail contact can provide fast solutions, but may not yield true values at optimization process with the condition that minimum distance is zero can time-consuming. A compound method, combining the Newton-Rhapson methods the optimization process method is proposed to provide exact solutions efficiently.

EFFICIENT COMPUTATION OF THE ACCELERATION OF THE CONTACT POINT BETWEEN ROTATING SURFACES AND APPLICATION TO CAM-FOLLOWER MECHANISM

  • LEE K.
    • International Journal of Automotive Technology
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    • v.7 no.1
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    • pp.115-120
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    • 2006
  • On a rotating contact surface of arbitrary shape, the relative velocity of the contact point sliding between the surfaces is computed with the basic geometries of the rotating surfaces, and the acceleration of the contact point between the contact surfaces is computed by using the relative velocity of the contact point. Thus the equation for the acceleration constraint between the contact surfaces in muitibody dynamics is not coupled with the parameters such as the relative velocity of the contact point. In case of the kinematic analysis, the acceleration of the contact point on any specific instant may also be efficiently computed by the present technique because the whole displacement of a full cycle need not be interpolated. Employing a cam-follower mechanism as a verification model, the acceleration of the contact point computed by the present technique is compared with that computed by differentiating the displacement interpolated with a large number of nodal points.

Landing Gear 2 Degree of Freedom Modeling and Optimization (착륙장치 2 자유도 동적 모델링 및 최적설계)

  • Lee, Seung-Gyu;Shin, Jeong-Woo;Kim, Tae-Uk
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.23 no.1
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    • pp.56-61
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    • 2015
  • Because of kinematic complexities, nonlinear behavior, etc, the performance of oleo-pneumatic landing gear is predicted by qualified commercial softwares. While commercial softwares predict more exactly, it takes a long time to construct or modify a model. At initial design stage, design parameters can be determined quickly and exactly enough with simple 2 degree of freedom model of mass, spring and damping. 2 degree of freedom model can be easily applied to optimization and reliability analysis which takes repetitive computation. In this paper, oleo-pneumatic landing gear is modeled as a nonlinear 2 degree of freedom model. The analysis are compared with landing gear drop test. To determine design parameter, optimization problem is solved with genetic algorithm and 2 degree of freedom model.

The Effect of Using a Two Step Verbal Cue to a Visual Target above Eye Level on the Parkinsonian Gait (파킨슨병 환자 보행에서 눈 높이 위수준의 시작 목표에 대한 두 걸음 구두 암시의 효과)

  • Kim, Jong-Man;Ahn, Duk-Hyun;Choi, Woon-Sung
    • Physical Therapy Korea
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    • v.1 no.1
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    • pp.92-97
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    • 1994
  • It is well known that visual cues can improve the motor performance of Parkinsonian patients. Previous laboratory studies have examined the effects of visual cueing to the floor. This case study examined the effects of using a visual cue above eye level on the gait of a Parkinsonian man. It was found that cueing the patient to a target above eye level while waking not only improved the kinematic parameters of the gait cycle but also facilitated a more functional gait pattern with re-intergration of arm swing, rhythm, heel strike and a more erect posture. Visual targeting above eye level may serve as an important clinical tool for physiotherapists treating Parkinsonian patients.

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A Research about optimum design of the walking robot using Jansen mechanism (얀센 메커니즘을 이용한 보행로봇의 최적설계에 관한 연구)

  • YONGZHU, JIN;Chi, Hyoung Geun
    • Proceeding of EDISON Challenge
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    • 2016.03a
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    • pp.384-388
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    • 2016
  • This paper proposed a m.Sketch to search the optimal link lengths for a legged walking robot. In order to apply the m.Sketch for the proposed, set the design parameters of the constraints and use the m.Skecth to get optimal GL(Groud Length) and GAC(Ground Angle Coefficient). The legged robot designed based on four-bar linkage theory and Theo Jansen mechanism. The stride length of the legged walking robot was defined based on the proposed kinematic analysis. Use the Edison Design m.Sketch simulate and find the optimal link length having the best of the Ground Length (GL) and Ground Angle Coefficient(GAC). And use these length implemented the Theo Jansen mechanism both in Science box parts and acrylic. In addition to the further expansion of the legs to reach the goaltranslating heavy objects or person.

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