• Title/Summary/Keyword: JOINT

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Inverse dynamic analysis of flexible robot arms with multiple joints (다관절 유연 로보트 팔의 역동력학 해석)

  • 김창부;이승훈
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10a
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    • pp.254-259
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    • 1992
  • In this paper, we propose an optimal method for the tracking a trajectory of the end-effector of flexible robot arms with multiple joints. The proposed method finds joint trajectories and joint torques necessary to produce the desired end-effector motion of flexible manipulator. In inverse kinematics, optimized joint trajectories are computed from elastic equations. In inverse dynamics, joint torques are obtained from the joint equations by using the optimized joint trajectories. The equations of motion using finite element method and virtual work principle are employed. Optimal control is applied to optimize joint trajectories which are computed in inverse kinematics. The simulation of flexible planner manipulator is presented.

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Nonlinear Damper Model for the Quantification of joint Mechanical Properties (관절계 역학적 특성의 정량화를 위한 비선형 댐퍼모델)

  • EOM Gwang-Moon;LEE Chang-Han;KIM Chul-Seung;Heo Ji-Un
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.4
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    • pp.188-193
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    • 2005
  • The purpose of this paper is to develop a more precise damper model of the joint for the quantification of the joint mechanical properties. We modified the linear damper model of a knee joint model to nonlinear one. The normalized RMS errors between the simulated and measured joint angle trajectories during passive pendulum test became smaller with the nonlinear damper model than those of the linear one which indicates the nonlinear damper model is better in precision and accuracy. The error between the experimental and simulated knee joint moment also reduced with the nonlinear damper model. The reduction in both the trajectory error and the moment error was significant at the latter part of the pendulum test where the joint angular velocity was small. The nonlinearity of the damper was significantly greater at thin subject group and this indicates the nonlinearity is a useful index of joint mechanical properties.

Properties of Mechanical Joint by Carbon Fiber/Epoxy Sandwich Composite Panels (탄소섬유/Epoxy 샌드위치 복합재판넬의 기계적 취부특성평가)

  • Oh, K.;Lee, S.;Jeong, J.;Cho, S.;Kim, J.
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.04a
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    • pp.121-124
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    • 2005
  • This paper was about experimental test properties by mechnical joint of CF1263/Epoxy Al honeycomb panels. In case of mechanical joint using screw, nut shall be secured over than minimize third screw pitch. In case of insert backsheet for increase of joint force, increase weight for assemble by screw pitch. In case of insert backsheet with CF1263/Epoxy, predominant save weight and minimazer of displacement by tensile weight moreover predominant strength. In case of mechanical joint by rivet, rivet of Monobolt has over-hole in hole of CF1263/Epoxy but rivet of PROTRUDING has predominant of mechanical joint.

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A study on the design of the press fit joint for automotive aluminum/composite hybrid propeller shaft (자동차용 알루미늄/복합재료 하이브리드 동력전달축의 압입접합부 설계에 관한 연구)

  • Kim, Hak-Sung;Lee, Dai-Gil
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.226-231
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    • 2004
  • Press fitting method for joining of a hybrid tube and steel ring with small teeth for automotive aluminum/composite hybrid propeller shaft was devised to improve reliability and to reduce manufacturing cost, compared to other joining methods such as an adhesively bonded joint, bolted joint or welded joint. To obtain high strength of the press fit joint, an optimal design method for the teeth was devised with respect to number and shape of the steel teeth. Torsional static, fatigue tests and finite element analysis of the press fit joint were performed with respect to experimental variables. The developed optimal design method predicted well the static torque capability and failure mode of the press fit joint. Also, it provided design guide line of press fit joint for improving torsional static and fatigue characteristics.

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Joint Characteristics in Layered Rocks (층상 암석에서 절리의 특성 연구)

  • Chang, Tae-Woo
    • The Journal of Engineering Geology
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    • v.19 no.2
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    • pp.145-152
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    • 2009
  • Joints are planar tensile opening-mode fractures whose relative motion, as the fracture propagates, is perpendicular to bedding plane and occur in a systematic manner to form a joint set. This paper discusses the mechanical control of joint propagation, the relationship between join spacing and layer thickness, the join saturation, the frequency distribution of join spacing, the joint density, the cross joint, and the development mechanism of joint from a lot of recent joint studies in sedimentary rocks.

Basic Concepts of Joint Motion in Peripheral Joint Mobilization (관절 모빌리제이숀에 있어서 관절운동의 기본개념)

  • Park Ji-Whan
    • The Journal of Korean Physical Therapy
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    • v.6 no.1
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    • pp.155-161
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    • 1994
  • Joint mobilization refers to techniques that are used to treat joint dysfunction such as when there is stiffness reversible joint hypomobility, or pain. Currently there are several schools of thought and treatment techniques that are popular in the United States. and leading practitioners and educators are attempting to blend common points to yield more uniform treatment from the various approaches. In order to effectively use joint mobilization for treatment, the practitioner must know and be able to evaluate the anatomy, arthrokinematics, and pathology of the neuromusculoskeletal system and to recognize when the techniques are indicated or when other stretching techniques would be more effective for regaining lost motion. Indiscriminate use of joint mobilization techniques when tot indicted could lead to potential harm to the patient's joints.

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Measurement of electrical resistance at the Nb_{3}$Sn CICC joint fabricated by sub-cable to sub-cable joining (Nb_{3}$Sn 초전도 CICC의 sub-cable to sub-cable 접합 및 접합저항 측정)

  • 이호진;홍계원;김기백;권선칠;김기만
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 1999.02a
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    • pp.89-92
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    • 1999
  • A small scale joint sample of Nb3Sn CICC was fabricated by sub-cable to sub-cable joining. This joint was produced by parallel insertion of one end of each sub-cable into the sub-cable space of the other side of cable, which can decrease the equivalent electrical resistance at the joint is expected to have average properties, dc resistance and ac losses, in view of the shapes of ITER type joint and strand to strand joint. The 3.8nOhm of dc resistance was measured in the range of 10-200A transport current. The normalized resistivity of the joint was about 6.7 $\mu}$Ohm-$^mm{2}$. Considering the normalized resistivity, the full scale joint prepared by sub-cable to sub-cable joining may have similar joint dc resistance with other conventional full scale joints with a shorter joining length.

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Numerical Parametric Study of Offshore K-Joint Structure (해양 K-Joint 구조의 수치해석 연구)

  • Park Kwan-Kyu;Im Sung-Woo;Jo Chul-Hee
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.603-611
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    • 2006
  • The fundamental joint configuration that is often applied in offshore structures is the K-joint. The paper describes a numerical parametric study for K-joint parameters (using the finite element program) and compared with results of the experimental test. The stress effects of various parameters including $\alpha,\;\beta,\;\gamma,\;\tau\;and\;\theta$ were investigated. The paper introduces the stress distributions as per each parameter. From the study, the maximum stress of joint became different according to the variation of joint parameters.

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Stress Analysis of Double T-Welded Joints Considering External Forces (외력을 고려한 양면 T-용접이음부의 음력해석)

  • 김성환;방한서;방희선;송관형
    • Journal of Welding and Joining
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    • v.19 no.2
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    • pp.215-220
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    • 2001
  • In the T-joint welding, the complete penetration joint which is obtained by groove welding with edge preparation is generally required thor the safety and reliability of structures but this way have the some defects such as increase of working time, consumed welding electrode quantity and large welding deformation. If there is no probrem, in the strength, T-joint welding without edge preparation will be profitably understood in the economical and welding deformation side. In this paper, we performed the finite element analysis to understand the characteristics of welding residual stresses on two models, complete penetration joint have the edge preparation and incomplete penetration joint without edge preparation, respectively. Especially, we observed the relation between welding residual stress distributed on the notch of gap in the root and external force in the incomplete penetration joint without edge preparation.

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Relationships between Toddler-teacher Joint Attention and Toddlers' Vocabularies (어린이집에서 24-36개월 영아-교사 간 공동주의와 영아의 어휘력간의 관계)

  • Kim, Myung-Soon;Lee, Ka-Hyun
    • Korean Journal of Child Studies
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    • v.30 no.5
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    • pp.155-165
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    • 2009
  • This study was conducted to identify relationships between toddler-teacher joint attention and toddlers' vocabularies. Toddlers' vocabularies were assessed by the MacArthur Communicative Development Inventory-Korean (MCDI-K) modified by Kim (2006); joint attention episodes were observed by classification categories for engagement condition (Bakeman & Adamson, 1984). Data were analyzed by means, t-test and Pearson's correlations. Results were that : (1) receptive vocabulary of toddlers was about 1.1 times as high as their expressive vocabulary. (2) Coordinated joint attention was observed most frequently, followed by supported joint attention; coordinated joint attention was closely related to support joint attention. (3) The relationship between toddler-teacher joint attention and toddlers' vocabularies were significant in a positive direction.

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