• Title/Summary/Keyword: kinematic

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실시간 동적 GPS 측량에 의한 지형 해석 (Analysis of Topography by Real-Time Kinematic GPS Positioning)

  • 신상철;김정동;박운용
    • 한국측량학회지
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    • 제19권3호
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    • pp.263-272
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    • 2001
  • 반송파 위상을 이용하는 고정밀도의 실시간 동적 GPS측량을 위해 OTF초기화에 따른 위치결정 정확도는 20km의 기선거리 범위 내에서는 5분 이상의 초기화로 1cm이내의 정확도로 기선을 결정할 수 있었으며, 위성의 기하학적인 배치상태가 측위 정확도에 미치는 영향은 크므로 PDOP과 RDOP은 4.0 이하를 유지할 수 있는 시간대를 계획하는 것이 좋다고 판단된다. 실시간 동적 GPS측량을 위한 초기 조건과 관측 시간대를 고려한 다음, 후처리에 의한 연속 동적 GPS측량과 실시간 동적 GPS측량을 수행하였다. 본 연구를 위해 실시간으로 GPS 관측 자료를 저장할 수 있는 프로그램을 개발하여 결과값을 동시에 저장하고 controller를 통해 관측 당시의 위성 상태를 모니터링 할 수 있는 시스템을 제안하였다. 그 결과 측량시 발생할 수 있는 오차 요소에 대한 보정이 가능하여 정확도 향상에 기여함을 알 수 있었다.

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복싱 국가대표선수 라이트 스트레이트 펀치 동작의 Kinematic 특성분석-사례연구 (The Case Study of A Kinematic Analysis of the Right-Straight Punch in Korean National Representative Boxers)

  • 김의환;김진표;이진욱
    • 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.

협소 공간 작업을 위한 6축 다관절 로봇의 기구학 및 구조해석 (Kinematic and Structural Analysis of a 6-DOF Manipulator for Narrow-space Work)

  • 정성엽;최두순
    • 한국산학기술학회논문지
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    • 제18권3호
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    • pp.666-672
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    • 2017
  • 본 연구팀은 프레스 성형 공정에서 버텀 섀시 (bottom chassis)에 팸너트 (pem nut)를 고정하는 것과 같은 협소 공간 작업을 위한 6축 다관절 로봇을 개발하고 있다. 본 논문에서는 6축 다관절 로봇의 위치 제어를 위한 기구학 해석과 가반하중에 따른 위치 정밀도 파악을 위한 구조해석을 수행하였다. 먼저, 로봇의 Denavit-Hatenberg 파라미터를 정의하고, 정기구학과 역기구학 모델을 제시하였다. 기구학 모델은 Coppelia Robotics 사의 virtual robot experimentation platform (V-REP)을 이용하여 시각적인 시뮬레이션을 통해 검증하였다. 위치 정밀도 분석은 완전 펼침 상태와 완전 접힘 상태에서 자중에 의한 처짐량과 가반하중에 의한 처짐량에 대한 구조해석을 통해 수행하였다. 해석 결과, 최대 변형량은 완전 펼침 상태에서 자체 하중만 있는 경우 0.339 mm로 나타났으며, 5kgf의 하중이 장착된 경우에는 0.667 mm로 나타났고, 설계 조건 1 mm 내에 있음을 확인하였다. 또한, 최대 발생 응력은 축 2와 3을 연결하는 링크에서 22.05 MPa로 나타났고, 부품 재질을 고려할 때 이 값은 구조적으로 안전함을 확인하였다.

기구학적 운동이 돼지 무릎 관절연골의 마찰계수 변화에 미치는 영향 (Effect of Kinematic Motion on Changes in Coefficients of Friction of Porcine Knee Joint Cartilage)

  • 김환;김충연;이권용;김대준;임도형
    • Tribology and Lubricants
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    • 제29권1호
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    • pp.46-50
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    • 2013
  • In this study, the frictional behaviors of articular cartilage against a Co-Cr alloy in two types of kinematic motions were compared. Cartilage pins were punched from the femoral condyles of porcine knee joints, and Co-Cr alloy disks were machined from orthopedic-grade rods and polished to a surface roughness ($R_a$) of 0.002. Friction tests were conducted by using a pin-on-disk-type tribotester in phosphate buffered saline (PBS) under pressures of 0.5, 1, and 2 MPa. All tests were performed in the repeat pass rotational (ROT) and the linear reciprocal (RCP) sliding motions with the same sliding distance and speed of 50 mm/s. The coefficients of friction of the cartilage against the Co-Cr alloy increased with the sliding time in both kinematic motions for all contact pressures. The maximum coefficients of friction in RCP motion were 1.08, 2.82, and 1.96 times those in ROT motion for contact pressures of 0.5, 1, and 2 MPa, respectively. As the contact pressure increased, the coefficients of friction gradually increased in RCP motion, whereas they decrease and then increased in ROT motion. The interaction between the directional change of the shear stress and the orientation of collagen fiber in the superficial layer of the cartilage could affect the change in the frictional behaviors of the cartilage. A large difference in the coefficients of friction between the two kinematic motions could be interpreted as differences in the directional change of shear stress at the contact surface.

회전기 및 착지기 분리 구동을 가능케 하는 새로운 무릎 보장구의 기구부 설계 (A Novel Kinematic Design of a Knee Orthosis to Allow Independent Actuations During Swing and Stance Phases)

  • 표상훈;김갑순;윤정원
    • 제어로봇시스템학회논문지
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    • 제17권8호
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    • pp.814-823
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    • 2011
  • Nowadays many neurological diseases such as stroke and Parkinson diseases are continually increasing. Orthotic devices as well as exoskeletons have been widely developed for supporting movement assistance and therapy of patients. Robotic knee orthosis can compensate stiff-knee gait of the paralyzed limb and can provide patients consistent assistance at wearable environments. With keeping a robotic orthosis wearable, however, it is not easy to develop a compact and safe actuator with fast rotation and high torque for consistent supports of patients during walking. In this paper, we propose a novel kinematic model for a robotic knee orthosis to drive a knee joint with independent actuation during swing and stance phases, which can allow an actuator with fast rotation to control swing motions and an actuator with high torque to control stance motions, respectively. The suggested kinematic model is composed of a hamstring device with a slide-crank mechanism, a quadriceps device with five-bar/six-bar links, and a patella device for knee covering. The quadriceps device operates in five-bar links with 2-dof motions during swing phase and is changed to six-bar links during stance phase by the contact motion to the patella device. The hamstring device operates in a slider-crank mechanism for entire gait cycle. The kinematics and velocity/force relations are analyzed for the quadriceps and hamstring devices. Finally, the adequate actuators for the suggested kinematic model are designed based on normal gait requirements. The suggested kinematic model will allow a robotic knee orthosis to use compact and light actuators with full support during walking.

로봇 매니플레이터의 실시간 특이점 회피를 위한 작업 재구성법: 동적 작업 우선도에 기초한 해석 (Task Reconstruction Method for Real-Time Singularity Avoidance for Robotic Manipulators : Dynamic Task Priority Based Analysis)

  • 김진현;최영진
    • 제어로봇시스템학회논문지
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    • 제10권10호
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    • pp.855-868
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    • 2004
  • There are several types of singularities in controlling robotic manipulators: kinematic singularity, algorithmic singularity, semi-kinematic singularity, semi-algorithmic singularity, and representation singularity. The kinematic and algorithmic singularities have been investigated intensively because they are not predictable or difficult to avoid. The problem with these singularities is an unnecessary performance reduction in non-singular region and the difficulty in performance tuning. Tn this paper, we propose a method of avoiding kinematic and algorithmic singularities by applying a task reconstruction approach while maximizing the task performance by calculating singularity measures. The proposed method is implemented by removing the component approaching the singularity calculated by using singularity measure in real time. The outstanding feature of the proposed task reconstruction method (TR-method) is that it is based on a local task reconstruction as opposed to the local joint reconstruction of many other approaches. And, this method has dynamic task priority assignment feature which ensures the system stability under singular regions owing to the change of task priority. The TR-method enables us to increase the task controller gain to improve the task performance whereas this increase can destabilize the system for the conventional algorithms in real experiments. In addition, the physical meaning of tuning parameters is very straightforward. Hence, we can maximize task performance even near the singular region while simultaneously obtaining the singularity-free motion. The advantage of the proposed method is experimentally tested by using the 7-dof spatial manipulator, and the result shows that the new method improves the performance several times over the existing algorithms.

Three-dimensional kinematic motion analysis of door handling task in people with mild and moderate stroke

  • Lee, Jung Ah;Kim, Eun Joo;Hwang, Pil Woo;Park, Han Ram;Bae, Jae Hyuk;Kim, Jae Nam
    • Physical Therapy Rehabilitation Science
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    • 제5권3호
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    • pp.143-148
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    • 2016
  • Objective: This study aimed to quantify one of the useful upper extremity movements to evaluate motor control abilities between the groups of people with mild and moderate arm impairments performing a door handling task. Design: Cross-sectional study. Methods: Twenty-one healthy participants and twenty-one persons with chronic stroke (9 mild stroke and 12 moderate stroke) were recruited for this study. Stroke participants were divided into 2 groups based on Fugle-Meyer Assessment scores of 58-65 (mild arm) and 38-57 (moderate arm). All they performed door handling task including the pronation and supination phases 3 times. We measured some movement factors which were reaction time, movement time, hand of peak velocity, hand of movement units to perform door handling task using the three-dimensional motion analysis. Results: The majority of kinematic variables showed significant differences among study groups (p<0.05). The reaction time, total and phase of movement time, hand of peak velocity, the number of movement units discriminated between healthy participants and persons with moderate upper limb stroke (p<0.05). In addition, reaction time, total and phase of movement time, the number of movement units discriminated between those with moderate and mild upper limbs of stroke patients (p<0.05). Conclusions: Three-dimensional kinematic motion analysis in this study was a useful tool for assessing the upper extremity function in different subgroups of people with stroke during the door handling task. These kinematic variables may help clinicians understand the arm movements in door handling task and consist of discriminative therapeutic interventions for stroke patients on upper extremity rehabilitation.

닫힌사슬에서의 PNF 대각선 패턴을 이용한 몸통 전·후방 이동운동이 뇌졸중환자의 상지 기능 및 일상생활에 미치는 영향 -단일 사례 연구- (Effect of Forward-and-Backward Shift Trunk Exercise Using Proprioceptive Neuromuscular Facilitation Diagonal Pattern in Closed Kinematic Chain Exercises on Upper Limb Function and ADL in Stroke Patient -A Single-Subject Design-)

  • 박시은;문상현
    • PNF and Movement
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    • 제15권3호
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    • pp.237-246
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    • 2017
  • Purpose: The purpose of this study was to investigate the effects of forward-and-backward shift trunk exercise using a proprioceptive neuromuscular facilitation (PNF) diagonal pattern in a closed kinematic chain exercise on the upper limb function and activity of daily living (ADL) in a stroke patient. Methods: One subject participated in this study. The study used a reversal A-B-A' design, where A and A' were the baseline period (no intervention), and B was the intervention period. The intervention was a forward-and-backward trunk shift exercise, using a PNF diagonal pattern on both a stand-on-hand position and a quadruped position of closed kinematic chain exercises, for 20 min per day for 2 weeks. The range of motion (ROM) of the shoulder joint was measured and a Fugl-Meyer assessment of upper extremity (FMA-UE) and a functional independence measure (FIM) were performed to measure upper limb function and activity of daily living (ADL). Results: ROMs of shoulder joint (flexion, extension, abduction, and external rotation) increased in the intervention phase. The FMA-UE score increased (from 28 to 36) in the intervention phase. The FIM score increased (from 20 to 25) in the intervention phase. These increases were maintained after intervention (Baseline II). Conclusion: These results suggest that forward-and-backward shift trunk exercises using a PNF diagonal pattern in a closed kinematic chain exercise have a positive effect on stroke patients' upper limb function and ADL ability.

A Position based Kinematic Method for the Analysis of Human Gait

  • Choi Ahn Ryul;Rim Yong Hoon;Kim Youn Soo;Mun Joung Hwan
    • Journal of Mechanical Science and Technology
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    • 제19권10호
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    • pp.1919-1931
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    • 2005
  • Human joint motion can be kinematically described in three planes, typically the frontal, sagittal, and transverse, and related to experimentally measured data. The selection of reference systems is a prerequisite for accurate kinematic analysis and resulting development of the equations of motion. Moreover, the development of analysis techniques for the minimization of errors, due to skin movement or body deformation, during experiments involving human locomotion is a critically important step, without which accurate results in this type of experiment are an impossibility. The traditional kinematic analysis method is the Angular-based method (ABM), which utilizes the Euler angle or the Bryant angle. However, this analysis method tends to increase cumulative errors due to skin movement. Therefore, the objective of this study was to propose a new kinematic analysis method, Position-based method (PBM), which directly applies position displacement data to represent locomotion. The PBM presented here was designed to minimize cumulative errors via considerations of angle changes and translational motion between markers occurring due to skin movements. In order to verify the efficacy and accuracy of the developed PBM, the mean value of joint dislocation at the knee during one gait cycle and the pattern of three dimensional translation motion of the tibiofemoral joint at the knee, in both flexion and extension, were accessed via ABM and via new method, PBM, with a Local Reference system (LRS) and Segmental Reference system (SRS), and then the data were compared between the two techniques. Our results indicate that the proposed PBM resulted in improved accuracy in terms of motion analysis, as compared to ABM, with the LRS and SRS.

보행의 운동학적 데이터를 이용한 지면반발력 계산 (Computation of Ground Reaction Forces During Gait using Kinematic Data)

  • 송성재;김세윤;김영태;이상돈
    • 대한기계학회논문집A
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    • 제34권4호
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    • pp.431-437
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    • 2010
  • 본 연구의 목적은 편마비 환자와 같이 정상 보행이 아닌 경우의 보행 실험에서 힘측정판을 이용한 지면반발력의 측정이 매우 어려웠던 경험에서 출발하여 힘측정판을 사용하지 않고 운동학적 데이터만으로 보행 중 발생하는 지면반발력을 계산하는 것이다. 3차원 동작분석 시스템과 동기화된 힘측정판을 이용하여 보행실험을 실시하여 3차원 동작분석 시스템으로부터 보행의 운동학적 데이터를 추출하였고 이로부터 보행주기를 검출하였다. 인체를 13개의 체절로 모델링하고 각 체절의 거동이 추출한 운동학적 데이터를 따르도록 하였다. 각 체절의 질량과 질량 중심은 인체측정학의 자료를 이용하였다. 보행실험에서 측정한 지면반발력과 운동학적 데이터만을 이용한 계산 결과의 비교에서 크기가 가장 큰 수직방향은 잘 일치하였고 전후방향이나 횡방향도 유사한 경향을 보였다. 본 계산 결과는 보행에 관한 역동역학 해석의 기본 자료로 활용할 수 있다.