• 한국운동역학회지
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• 제13권3호
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• pp.293-309
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• 2003

The purpose of this study was to analyze the kinematic variables of the right-straight punch(RSP) in boxing with three-dimensional analysis technical methods. The subjects are boxers who have been playing in national boxing representative team and the RSP is their special favorite technique, The right-straight punches were filmed on 16mm video cameras(30frames/sec.) The kinematic variables were temporal, postural and center of gravity(COG). The mean and the standard deviation of variables have been obtained and used as basic factors for examining characteristics of the RSP by out-boxers. From the data analysis and discussion, the following conclusions have been drawn. 1) Temporal variables It is a significant characteristic that LDJ and KDM s' the amount of elapsed time(EF) needed for both an attack and a defense were similar : ET for stretch-out of attack-arm was $0.52{\pm}0.04\;sec$. and return was $0.54{\pm}0.01\;sec$. Therefore, a defense motion is as important as an attack motion. 2) Posture variables When the subjects performed a RSP, the significant characteristic of the ankle angle was that it wasn't completely returned to the original position after stretching-out. Therefore it is necessary to do supplementary exercises, such as side steps, to move the center of gravity more effectively. The hee angle was not fully stretched either. In regard to the hip angle, it should be rotated with all strength to harmonize with the direction of movement. 3) Center of Gravity(COG) variables When both LDJ and KDM performed a RSP, a significant characteristic was the transformation of sagittal view rather than transverse or frontal views.

• The Journal of Korean Physical Therapy
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• 제22권2호
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• pp.15-23
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• 2010

Purpose: This study was done to establish reference data for temporo-spatial, kinematic and kinetic parameters for normal Koreans as they age. Methods: Normal adults and children without a previous history of musculoskeletal problems were enrolled in this study. The normal subjects were divided by age into three groups: Group I: children ($11.95{\pm}0.29$ years); Group II: young adults ($23.90{\pm}3.67$ years); Group III: older adults ($71.40{\pm}4.08$ years). The temporo-spatial and kinematic data were measured using 6 MX3 cameras while each subject walked through a 10 m walkway at a self-selected speed. The kinetic data were measured using 2 force plates and were calculated by inverse dynamics. Results: Motion patterns are typically associated with a specific phase of the gait cycle. Our results were as follows: 1. There were significant differences between the different age groups in temporo-spatial parameters such as cadence, double support, time of foot off, stride length, step length, and walking speed. 2. There were significant differences between the groups in kinematic parameters such as range of motion (ROM) of the hip, knee and ankle in the sagittal plane, ROM of the pelvis, hip and knee in the coronal plane and ROM of the pelvis, hip and ankle in the transverse plane. 3. There were significant differences between the groups in kinetic parameters such as joint moments of force, joint mechanical power generation or absorption and ground reaction forces. Conclusion: The results of this study can be utilized (a) as a reference for kinematic and kinetic data of gait analysis in normal Koreans, and (b) as an aide in evaluating and treating patients who have problems relating to gait.

• 대한조선학회논문집
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• 제50권1호
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• pp.41-48
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• 2013

Several fatigue damages have recently been reported which cannot be resolved in the context of the existing fatigue design procedure, and they are suspected to be the cracks induced by the low cycle fatigue mechanism. To tackle the problem, a series of material tests together with fatigue tests have been carried out, and elasto-plastic notch strain analysis using nonlinear kinematic hardening model has been performed. The cyclic stress-strain curves are obtained and the nonlinear kinematic hardening model was calibrated based on the obtained material data. Also, the fatigue test with non-load-carrying cruciform fillet welded joint has been performed in low cycle fatigue regime. Then, the notch strain analyses have been carried out to find the precise elasto-plastic behavior of the material at the notch root of the cruciform joint. The variation of the material property from the base metal via HAZ up to the weld metal was taken into account using spatial variation of the material property. Then the detail elasto-plastic behavior of the welded joint subjected to the repeated cyclic loading has been investigated further through the comparison with the prediction with Neuber's rule. The calibration of the nonlinear kinematic hardening model and nonlinear notch strain analyses have been performed using the commercial FE program ABAQUS.

• 한국산학기술학회논문지
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• 제15권5호
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• pp.2989-2995
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• 2014

본 연구는 정상 성인의 팔 움직임 종류에 따른 운동형상학적인 변화를 알아보기 위함이다. 45명의 정상 성인을 대상으로 네 가지 팔 움직임 종류인, 정상 팔 움직임 보행, 한 팔 움직임 보행, 두 팔 움직임 억제 보행, 파워 보행의 순서대로 실시하였다. 실험 대상자가 10m의 보행거리를 자연스럽게 걷는 동안 3차원 보행분석기인 Vicon동작 분석기의 6MX3카메라를 이용해서 측정을 하였다. 이 실험의 자료는 2010년 6월부터 8월까지 수집되었다. 팔 움직임에 따른 운동 형상학적 보행변수의 변화는 정상과 비교해 시상면에서 오른쪽 골반, 엉덩관절의 관절 운동범위, 관상면에서 골반, 엉덩관절, 허리부위에 관절 운동범위, 횡단면에서는 골반, 가슴부위, 허리부위의 관절 운동범위에서 차이를 나타냈다(p<.05). 본 연구의 결과 팔 움직임의 형태에 따라 보행을 하게 되면 운동 형상학적 변화를 나타내고, 이러한 연구 결과는 임상에서 정상인과 환자들의 보행 비교 자료로 사용될 수 있을 것이다.

• 대한통합의학회지
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• 제10권1호
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• pp.91-99
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• 2022

Purpose : The goal of this study is to examine the effect of robot assisted gait training (RAGT) on the kinematic factors (temporospatial gait parameters, gait cycle ratio, and gait line length) of gait in stroke patients. Methods : The subjects of this study were 24 stroke patients selected by inclusion criteria. Participants were randomly allocated to two groups: robot assisted gait training (n=11) and general neurological physical therapy group (n=11). In the robot-assisted gait training group, robot-assisted gait training was mediated for 30 minutes a day in addition to general neurological physical therapy. The general neurological physical therapy group was mediated by general neurological physical therapy for 30 minutes a day in addition to general neurological physical therapy. The number of interventions was 5 times a week for 5 weeks. In order to compare the kinematic factors of walking between the two groups, gait analysis was performed before and after 5 weeks of training using the Zebris gait analysis system. Results : As a result of the gait analysis of the two groups, there were significant differences in temporospatial gait variables (step length, stride length, step width, step time, stride time), gait cycle ratio (swing phase, stance phase) and gait line length. However, there was no significant difference in the cadence (temporospatial gait parameters) in the robot assisted gait training group compared to general neurological physical therapy group. Conclusion : It is considered to be a useful treatment for stroke patients to promote the recovery of gait function in stroke patients. Based on the results of this study, continuous robot assisted gait training treatment is considered to have a positive effect on gait ability, the goal of stroke rehabilitation. In the future, additional studies should be conducted on many subjects of stroke patients, the kinematic factors of the legs according to the severity of stroke and treatment period, and the effect of gait training.

• 소성∙가공
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• 제14권4호
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• pp.327-337
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• 2005

In the present work, the two back stress kinematic hardening models are proposed by combining Armstrong-Frederick, Phillips and Ziegler's hardening rules. Simple combination of hardening rules using simple rule of mixtures results in various evolutions of the kinematic hardening parameter. Using the combined hardening models the ultimate back stress fur the present models is also derived. The stress rate is co-rotated with respect to the spin of substructure due to the assumption of kinematic hardening rule in finite deformation regime. The work piece under consideration is assumed to consist of the elastic and the rigid plastic deformation zone. Then, the J2 deformation theory is facilitated to characterize the plastic deformation behavior under various loading conditions. The plastic deformation localization behaviors strongly depend on the constitutive description namely back stress evolution and its hardening parameters. Then, the analysis for Swift's effects under the fixed boundaries in axial directions is carried out using simple shear deformation.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.144-147
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• 2003

In order to evaluate spring-back behavior in automotive sheet forming processes, a panel shape idealized as a SS-rail has been investigated. After spring-back kas been predicted fer SS-rails using the finite element analysis, results has been compared with experimental measurements for three automotive sheets. To account for hardening behavior such as the Bauschinger and transient effects in addition to anisotropic behavior, the combined isotropic-kinematic hardening law based on the Chaboche type single-surface model and a recently developed non-quadratic anisotropic yield function have been utilized, respectively.

• 대한기계학회논문집A
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• 제25권3호
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• pp.339-352
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• 2001

The inverse kinematics problem of Stewart platform is straightforward, but no closed form solution of the forward kinematic problem has been presented. Since we need the real-time forward kinematic solution in MIMO control and the motion monitoring of the platform, it is important to acquire the 6 DOF displacements of the platform from measured lengths of six cylinders in small sampling period. Newton-Raphson method a simple algorithm and good convergence, but it takes too long calculation time. So we reduce 6 nonlinear kinematic equations to 3 polynomials using Nairs method and 3 polynomials to 2 polynomials. Then Newton-Raphson method is used to solve 3 polynomials and 2 polynomials respectively. We investigate operation counts and performance of three methods which come from the equation reduction and Newton-Raphson method, and choose the best method.

• 제어로봇시스템학회논문지
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• 제12권5호
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• pp.464-472
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• 2006

This paper presents the two degree-of-freedom (DOF) planar parallel mechanism, called the $2{\underline{R}}RR-RP$ manipulator, whose degree-of-freedom is dependent on an additional passive constraining leg connecting the base and the platform. First, the kinematic analysis of the mechanism is performed: the inverse and forward kinematic problems are analytically solved, the workspace is systematically derived, and all of the singular configurations are examined. Then, in order to determine the geometric parameters the optimization of the mechanism is performed considering its dexterity, stiffness, and space utilization. Finally, the kinematic performances of the optimized mechanism are evaluated through the comparison study to the conventional 5-bar parallel manipulator.

• 로봇학회논문지
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• 제14권4호
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• pp.251-257
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• 2019

This paper presents the kinematic modeling of the human forearm rotation constructed with a spatial four-bar linkage. Especially, a circumduction of the distal ulna is modeled for a minimal displacement of the position of the hand during the forearm rotation from the supination to the pronation. To establish its model, four joint types of the four-bar linkage are, firstly, assigned with the reasonable grounds, and then the spatial linkage having the URUU (Universal-Revolute-Universal-Universal) joint type is proposed. Kinematic analysis is conducted to show the behavior of the distal radio-ulna as well as to evaluate the angular displacements of all the joints. From the simulation result, it is, finally, revealed that the URUU spatial linkage can be substituted for the URUR (Universal-Revolute-Universal-Revolute) spatial linkage by a kinematic constraint.