• Title/Summary/Keyword: redundant joints

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Analysis of parallel manipulators with redundant joints (잉여 조인트 병렬형 로봇의 해석)

  • 김성복
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.371-374
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    • 1996
  • This paper presents the kinematic and dynamic analysis of parallel manipulators with redundant joints, obtained by putting additional active joints to an existing parallel manipulator. We develop the kinematic and dynamic models of a parallel manipulator with redundant joints. The redundancy in serial chain, due to the increased number of joints per limb, is considered in the modeling. Based oh the derived models, we define the kinematic and dynamic manipulabilities of a parallel manipulator with redundant joints. The effect of the redundant joints on the performance of parallel manipulators is analyzed in terms of kinematic and dynamic manipulabilities.

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Optimal Redundant Actuation of Parallel Manipulators with High Operational Stiffness (고강성 병렬형 로봇의 최적 여유 구동)

  • Kim, Sung-Bok
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.2
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    • pp.181-189
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    • 2000
  • This paper presents the optimal redundant actuation of parallel manipulators for complicated robotic applications such as cutting grinding drilling and digging that require a high degree of operational stiffness as well as the balance between force applicability and dexterity. First by taking into account the distribution(number and location) of active joints the statics and the operational stiffness of a redundant parallel manipulator are formulated and the effects of actuation redundancy are analyzed, Second for given task requirements including joint torque limit task force maximum allowable disturbance and maximum allowable deflection the task execution conditions of a redundant parallel manipulator are derived and the efficient testing formulas are provided. Third to achieve high operational stiffness while maintaining moderate dexterity the redundant actuation of a parallel manipulator is optimized which determines the optimal distribution of active joints and the optimal internal joint torque, Finally the simulation results for the optimal redundant actuation of a planar parallel manipulator are given.

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The Development of an Inverse Kinematic Solution for Periodic Motion of a Redundant Manipulator (여유자유도 로봇의 주기적 운동제어를 위한 역기구학 해의 개발)

  • 정용섭;최용제
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.1
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    • pp.142-149
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    • 1995
  • This paper presents a new kinematic control strategy for serial redundant manipulators which gives repeatability in the joint space when the end-effector undergoes some general cyclic motions. Theoretical development has been accomplished by deriving a new inverse kinematic equation that is based on springs being conceptually located in the joints of the manipulator. Although some inverse kinematic equations for serial redundant manipulators have been derived by many researchers, the new strategy is the first to include the free angles of torsional springs and the free lengths of the translational springs. This is important because it ensures repeatability in the joint space of a serial redundant manipulator whose end-effector undergoes a cyclic type motion. Numerical verification for repeatability is done in terms of Lie Bracket Condition. Choices for the free angle and torsional stiffness of a joint (or the free length and translational stiffness) are made based upon the mechanical limits of the joints.

Output Compliance Effects By Both Redundant Joint Compliances and Antagonistic Torques of A Spherical 3-DOF Mechanism (구형 3 자유도 메카니즘의 잉여관절 콤플라이언스와 상반토크로 인한 출력 콤플라이언스 효과)

  • 이준용;김희국
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.793-798
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    • 1996
  • In this paper, output compliance effects at RCC point by both redundant joint compliances and antagonistic torques generated by internal preloading between joints of a spherical 3 degree-of-freedom mechanism are investigated. For this purpose, kinematic analysis is briefly described. Then, output compliance models at RCC point, which is generated by redundant joint compliances and by internal preloading between joints are derived. Finally, ranges of output compliance modulation due to these redundant joint compliances and antagonistic torques are examined through simulation.

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Analysis of parallel manipulators with redundant limbs (잉여 다리 병렬형 로봇의 해석)

  • 김성복
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.730-733
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    • 1996
  • This paper presents the kinematic and dynamic analysis of parallel manipulators with redundant limbs, obtained by putting additional limbs to an existing parallel manipulator. We develop the kinematic and dynamic models of a parallel, manipulator with redundant limbs. The redundancy in parallelism due to the increased number of limbs and the redundancy in actuation due to the increased number of active joints are considered in the modeling. Based on the derived models, we define the kinematic and dynamic manipulabilities of a parallel manipulator with redundant limbs. The effect of the redundant limbs on the performance of parallel manipulators is analyzed in terms of kinematic and dynamic manipulabilities.

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Reconfiguration of Redundant Joints for Fault Tolerance of a Servo Manipulator (여유 자유도를 갖는 서보 매니퓰레이터의 내고장 제어를 위한 재형상 기법)

  • 박병석;안성호;윤지섭
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.10
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    • pp.899-906
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    • 2004
  • In this paper, fault tolerant algorithm is presented for a servo manipulator system. For fault tolerance of a servo manipulator system, reconfiguration algorithm accommodating a motor's failure has been presented. The algorithm considers a transport's degree of freedoms as redundant joints of a servo manipulator. The reconfiguration algorithm recovers the end effector's motion in spite of one motor's failure A modified pseudo inverse redistribution method has been proposed for the reconfiguration algorithm. Numerical examples and hardware tests have been presented to verify the proposed methods.

Configuration Control of a Redundant Manipulator Optimizing Stiffness and Joint Torque

  • Jin, Jaehyun;Ahn, Sungho;Jung, Jaehoo;Yoon, Jisup
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.104.5-104
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    • 2002
  • In this paper, we focus on a configuration control method of a redundant manipulator. The configuration of a redundant manipulator has been determined by geometry constraints and additional conditions, such as obstacle avoidance and dexterity optimization. This paper also utilizes optimization, and the additional condition (or performance index) to be optimized is stiffness of the end-effector and joints' torque. Stiffness and torque may be a natural attribute to be controlled during working and those vary as manipulator configuration does. So the optimal configuration from the viewpoint of stiffness and joint torque is studied. If the servo control mechanism of the joints Is assumed to be a...

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Fault Tolerant Control of a Servo Manipulator for Teleoperation by Control Allocation to Redundant Joints (여유 자유도에 대한 조종력 배분을 통한 원격작업용 서보 매니퓰레이터의 내고장 제어)

  • 진재현;박병석;안성호;윤지섭
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.4
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    • pp.235-245
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    • 2004
  • In this paper, fault tolerant mechanisms are presented for a servo manipulator system designed to operate in a hot cell. A hot cell is a sealed and shielded room to handle radioactive materials, and it is dangerous for people to work in the hot cell. So, remote operations are necessary to handle the radioactive materials in the hot cell. KAERI has developed a servo manipulator system to perform such remote operations. However, since electric components such as servo motors may fail by radiation, fault tolerant mechanisms have to be considered. For fault tolerance of the servo manipulator system, duplication mechanism increasing the reliability of the transport's driving motors and reconfiguration algorithm accommodating the slave's motor failure have been presented. The reconfiguration algorithm recovering the end effector's motion in spite of one motor's failure is based on control allocation redistributing redundant axes. The constrained optimization method and pseudo inverse method have been adopted for control allocation. Simulation examples and real test results have been presented to verify the Proposed methods.

Redundancy Utilizations of Redundant Robot Manipulators Based on Configuration Control (형태제어에 기초한, 여유자유도를 갖는 로보트 머니퓰레이터의 여유자유도 이용에 관한 연구)

  • ;Homayoun Seraji
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.41 no.4
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    • pp.422-432
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    • 1992
  • Previous investigations of redundant manipulators have often focussed on local optimization for redundancy resolution by using the Jacobian pseudoinverse to solve the instantaneous relationship between the joint and end-effector velocities. This paper establishes some new goals for redundancy resolution at position level by using configuration control approach which has been recently developed. Minimum gravity loading, joint limit avoidance, minimum sensitivity, maximum stiffness and minimum impulse are introduced as redundancy resolution goals. These new goals for redundancy resolution allow more efficient utilizations of the redundant joints based on the desired task requirements. Simple computer simulation examples are given for illustration.

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On the Singularities of Optimality Constraint-based Resolved Motion Methods for a Redundant Manipulator (여유 자유도 매니퓰레이터를 위한 지적 제한 조건을 기반으로 한 Resolved Motion 방법의 특이점에 관한 연구)

  • Cho, Dong-Kwon;Choi, Byoung-Wook;Chung, Myung-Jin
    • Proceedings of the KIEE Conference
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    • 1992.07a
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    • pp.386-390
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    • 1992
  • Algorithmic or kinematic singularities are inevitably a introduced if optimality criteria or augmented kinematic equations are used to resolve the redundancy of almost any manipulator with rotary joints. In this paper, a sufficient condition for a singularity-free optimal solution of the kinematic control of a redundant manipulator is derived and, specifically, algorithmic singularities are analyzed for optimality-based methods. A singularity-free space (SFS) to characterize the performance of a secondary task for a redundant manipulator using the sufficient condition for a redundant manipulator is defined. The SFS is a set of regions classified by the loci of configurations satisfying the inflection condition for manipulability measure in the Configuration space. Using SFS, the topological property of the Configuration space and the invertible workspace without singularities are analyzed.

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