• Title/Summary/Keyword: Kinematic analysis

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A new kinematic formulation of closed-chain mechanisms with redundancy and its applications to kinematic analysis

  • Kim, Sungbok
    • 제어로봇시스템학회:학술대회논문집
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    • 1995.10a
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    • pp.396-399
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    • 1995
  • This paper presents a new formulation of the kinematics of closed-chain mechanisms and its applications to obtaining the kinematic solutions and analyzing the singularities. Closed-chain mechanisms under consideration may have the redundancy in the number of joints. A closed-chain mechanism can be treated as the parallel connection of two open-chains with respect to a point of interest. The kinematics of a closed-chain mechanism is then obtained by imposing the kinematic constraints of the closed-chain on the kinematics of the two open-chains. First, we formulate the kinematics of a closed-chain mechanism using the kinematic constraint between the controllable active joints and the rest of joints, instead of the kinematic constraint between the two open-chains. The kinematic formulation presented in this paper is valid for closed-chain mechanisms with and without the redundancy. Next, based on the derived kinematics of a closed-chain mechanism, we provide the kinematic solutions which are more physically meaningful and less sensitive to numerical instability, and also suggest an effective way to analyze the singularities. Finally, the computational cost associated with the kinematic formulation is analyzed.

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Analysis on Kinematic Characteristics for a Translational 3-DOF Parallel Mechanism with Constrained Stewart Platform Structure (스튜워트 플랫폼 구조를 이용한 병진 3-자유도 병렬 메커니즘의 기구학 특성 분석)

  • 이석희;김희국;이병주
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.525-529
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    • 2004
  • A novel translational 3-dof parallel mechanism is proposed and analyzed. The mechanism consists of three RRPS serial subchains and an additional passive 3-dof type serial subchain. Three RRPS serial subchains alone may form a structure of the 6-DOF Stewart Platform mechanism. However, in the proposed mechanism, an additional passive serial subchain acts as constraints to restrict the output motion of the mechanism in 3-DOF translational space. The closed form position solutions of the proposed mechanism and its first-order kinematic model are derived. Then its workspace size and kinematic characteristics are examined via kinematic isotropic index.

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A kinematic Analysis of Binary Robot Manipulator using Genetic Algorithms

  • Gilha Ryu;Ihnseok Rhee
    • International Journal of Precision Engineering and Manufacturing
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    • v.2 no.1
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    • pp.76-80
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    • 2001
  • A binary parallel robot manipulator uses actuators that have only two stable states being built by stacking variable geometry trusses on top of each other in a long serial chain. Discrete characteristics of the binary manipulator make it impossible to analyze an inverse kinematic problem in conventional ways. We therefore introduce new definitions of workspace and inverse kinematic solution, and the apply a genetic algorithm to the newly defied inverse kinematic problem. Numerical examples show that our genetic algorithm is very efficient to solve the inverse kinematic problem of binary robot manipulators.

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Modeling of a 4-axis redundant stage by using SimMechanics (SimMechanics를 이용한 4축 과구동 스테이지의 모델링)

  • Lee, Jin-Young;Park, Won-Jun;Won, Chong-Jin;Jeong, Jay-I.
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.827-831
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    • 2008
  • In this paper, kinematic analysis for a planar 3-DOF redundant stage which has four actuators is presented by using SimMechanics software package. SimMechanics is a block sets of the Matlab/Simulink package. The SimMechanics enables a simplified model for a complex kinematic mechanism, since kinematic relationship between joints and linkages for the kinematic chains are expressed as line vectors and block diagrams. Here, positional error and limit values of movement ranges of the stage are evaluated by using the SimMechanics. The validity of the kinematic characteristics model was compared with theoretical kinematic analyses for the 3-DOF stage.

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Analysis on Kinematic Characteristics of the Revolute-joint-based Translational 3-DOF Parallel Mechanisms (회전관절만을 활용하는 병진 3자유도 병렬 메커니즘의 기구학 특성 분석)

  • Park, Jae-Hyun;Kim, Sung Mok;Kim, WheeKuk
    • The Journal of Korea Robotics Society
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    • v.10 no.2
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    • pp.119-132
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    • 2015
  • Two novel parallel mechanisms (PMs) employing two or three PaPaRR subchains are suggested. Each of those two PMs has translational 3-DOF motion and employs only revolute joints such that they could be adequate for haptic devices requiring minimal frictions. The position analyses of those two PMs are conducted. The mobility analysis, the kinematic modeling, and singularity analysis of each of two PMs are performed employing the screw theory. Then through optimal kinematic design, each of two PMs has excellent kinematic characteristics as well as useful workspace size adequate for haptic applications. In particular, by applying an additional redundantly actuated joint to the 2-PaPaRR type PM which has a closed-form position solution, it is shown that all of its parallel singularities within reachable workspace are completely removed and that its kinematic characteristics are improved.

Kinematic analysis of POSTECH Hand I with new symbolic notation

  • Choi, H.-R.;Chung, W.-K.;Youm, Y.
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10b
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    • pp.1764-1769
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    • 1991
  • Recently, dexterous mechanical hands have become of interest in the field of robotics. In this paper, a new symbolic C-Y notation is proposed for the kinematic modeling, and we solve the kinematics of a simplified model of POSTECH Hand 1, which is a 5 fingered, 20 degrees of freedom anthropomorphic hand. POSTECH Hand I is designed to have distinctive kinematic structure and the kinematic analysis of the hand is carried out using C-Y notation. To prove the feasibility of C-Y notation, D-H notation is also applied to the POSTECH Hand 1. In the inverse kinematic analysis, we neglect the fingertip geometry and assume the point contact with 3 degrees of freedom constraints. The configurations which optimize manipulability index[2] was obtained based on the simulation experiments on the SUN-4 graphic workstation using SUNPhigs graphic software.

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Kinematic Synthesis and Analysis of RSS-SC Suspension System Using Acceptable Tolerances of Motion (운동의 허용공차를 이용한 RSSS-SC 현장장치의 기구학적 설계)

  • 김선평;심재경
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.11
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    • pp.2672-2679
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    • 2000
  • In synthesizing and RSSS-SC mechanism that is the kinematic model of the McPherson strut suspension system in automobiles, the design equations for R-S, S-S and S-C dyads should be solved separately for a given set of prescribed positions. The number of prescribed positions that the RSSS-SC mechanism can be synthesized is up to three because of the S-C dyad. This limitation may cause unsatisfactory results in synthesized joint positions. This paper presents a kinematic synthesis method to place the joints of an RSSS-SC mechanism in desired boundaries by varying the prescribed positions of the mechanism within acceptable tolerances. The sensitivity analysis of the joint positions is used determine which displacement parameter should be altered to fulfill this task.

The Effect of PNF Arm Flexion Pattern on the Muscle Activation of Lower Extremity by Kinematic Chain Positions (사슬운동 자세에 따른 고유수용성신경근촉진법 팔 패턴이 다리의 근활성도에 미치는 효과)

  • Kim, Hee-Gwon;Seo, Yeon-Soon
    • PNF and Movement
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    • v.13 no.2
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    • pp.95-102
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    • 2015
  • Purpose: The purpose of this study was to analyze the effect of arm flexion patterns of proprioceptive neuromuscular facilitation on muscle activation in the contralateral lower extremity. Open kinematic chain and closed kinematic chain positions were used. Methods: This study used an electromyogram (MP150, Biopac Systems, USA) to measure muscle activation in 20 healthy male students. Comparative analysis was completed on muscle activation of the vastus lateralis, biceps femoris, tibialis anterior, and gastrocnemius of the contralateral lower extremity. Open kinematic chain and closed kinematic chain positions were used with a unilateral arm flexion-abduction-external rotation pattern. Paired t-tests using the SPSS 12.0 for Windows analyzed the data produced by the electromyogram. Results: There was a statistically significant difference in muscle activation in the biceps femoris, gastrocnemius, and tibialis anterior when the open kinematic chain and closed kinematic chain positions were compared (p < 0.05). Conclusion: The biceps femoris, gastrocnemius, and tibialis anterior muscles showed greater muscle activation in the closed kinematic chain position when compared to the open kinematic chain position.

Dynamic Analysis of Multi-Robot System Forcing Closed Kinematic Chain (복수로봇 시스템의 동력학적 연구-대상물과 닫힌 체인을 형성할때의 문제-)

  • 유범상
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.4
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    • pp.1023-1032
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    • 1995
  • The multiple cooperating robot system plays an important role in the research of modern manufacturing system as the emphasis of production automation is more on the side of flexibility than before. While the kinematic and dynamic analysis of a single robot is performed as an open-loop chain, the dynamic formulation of robot in a multiple cooperating robot system differs from that of a single robot when the multiple cooperating robots form a closed kinematic chain holding an object simultaneously. The object may be any type from a rigid body to a multi-joint linkage. The mobility of the system depends on the kinematic configuration of the closed kinematic chain formed by robots and object, which also decides the number of independent input parameters. Since the mobility is not the same as the number of robot joints, proper constraint condition is sought. The constraints may be such that : the number of active robot joints is kept the same as mobility, all robot joints are active and have interrelations between each joint forces/torques, two robots have master-slave relation, or so on. The dynamic formulation of system is obtained. The formulation is based on recursive dual-number screw-calculus Newton-Eulerian approach which has been used for single robot analysis. This new scheme is recursive and compact symbolically and may facilitate the consideration of the object in real time.