• Title, Summary, Keyword: Redundancy resolution

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Redundancy Resolution and Robust Control of Underwater Vehicle-Manipulator Systems with Minimizing Restoring Moment (수중 잠수정-매니퓰레이터 시스템의 복원력 최소화를 위한 여유 자유도 해석 및 강인 제어)

  • Han, Jong-Hui;Chung, Wan-Kyun
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.4
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    • pp.426-432
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    • 2009
  • In this paper, redundancy resolution of UVMS (underwater vehicle-manipulate. system) is addressed. In general, UVMS has redundant DOFs (degrees of freedom) as many as DOFs of manipulator and these redundant DOFs can be used to optimize the configuration of UVMS while satisfying given tasks. We propose a performance index for redundancy resolution which minimizes the restoring moments of UVMS. The restoring moment can cause unintentional change of poses of UVMS. If the restoring moments remain small, control effort for keeping the poses of UVMS decreases. This means that energy consumption can be reduced by minimizing the restoring moments during conducting tasks. Proposed performance measure is optimized by gradient projection method. Generated trajectories by this redundancy resolution are tracked by robust PID controller. Numerical simulations are presented to demonstrate performance of the proposed algorithm.

An Optimal Initial Configuration of a Humanoid Robot (인간형 로봇의 최적 초기 자세)

  • Sung, Young-Whee;Cho, Dong-Kwon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.1
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    • pp.167-173
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    • 2007
  • This paper describes a redundancy resolution based method for determining an optimal initial configuration of a humanoid robot for holding an object. There are three important aspects for a humanoid robot to be able to hold an object. Those three aspects are the reachability that guarantees the robot to reach the object, the stability that guarantees the robot to remain stable while moving or holding the object, and the manipulability that makes the robot manipulate the object dexterously. In this paper, a humanoid robot with 20 degrees of freedom is considered. The humanoid robot is kinematically redundant and has infinite number of solutions for the initial configuration problem. The complex three-dimensional redundancy resolution problem is divided into two simple two-dimensional redundancy resolution problems by incorporating the symmetry of the problem, robot's moving capability, and the geometrical characteristics of the given robot. An optimal solution with respect to the reachability, the stability, and the manipulability is obtained by solving these two redundancy resolution problems.

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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Motion Planning of Manipulators Using Kinematic Redundancy and ZMP Constraint Condition (기구학적 여유도와 ZMP 구속 조건을 이용한 매니퓰레이터의 동작 계획)

  • Choi, Jae-Yeon;Yoon, Hyun-Soo;Yi, Byung-Ju
    • The Journal of Korea Robotics Society
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    • v.6 no.4
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    • pp.308-316
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    • 2011
  • This work deals with development of effective redundancy resolution algorithms for the motion control of manipulator. Differently from the typical kinematically redundant robots that are attached to the fixed ground, the ZMP condition should be taken into account in the manipulator motion in order to guarantee the system stability. In this paper, a new motion planning algorithm for redundant manipulator not fixed to the ground is introduced. A sequential redundancy resolution algorithm is proposed, which ensures the ZMP (Zero Moment Point) stability, the planned operational motion, and additional sub-criteria such as joint limit index. A geometric constraint equation derived by reshaping the existing ZMP equation enables one to employ the sequential redundancy algorithm. The feasibility of the proposed algorithm is verified by simulating a redundant manipulator model.

Optimal control approach to resolve the redundancy of robot manipulators

  • Kim, Sung-Woo;Leen, Ju-Jang;Sugisaka, Masanori
    • 제어로봇시스템학회:학술대회논문집
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    • pp.234-239
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    • 1993
  • Most of the control problem is for the redundant manipulators use the pseudo-inverse control, thit is, the redundancy is resolved by the pseudo-inverse of the Jacobian matrix and then the controller is designed based on this resolution. However, this pseudo-inverse control has some problems when the redundant robot repeats the cyclic tasks. This is because the pseudo-inverse resolution is a local solution that generates the different configurations of the robot arm for the same hand position. Therefore it is necessary to find the global solution that maintains the optimal configuration of the robot for the repetitive tasks. In this paper, we want to propose a redundancy resolution method by the optimal theory that uses the calculus of variation. The problem formulations are : first to convert the optimal resolution problem to an optimal control problem and then to resolve the redundancy using the necessary conditions of optimal control.

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Analysis on the Kinematics and Dynamics of Human Arm Movement Toward Upper Limb Exoskeleton Robot Control - Part 2: Combination of Kinematic and Dynamic Constraints (상지 외골격 로봇 제어를 위한 인체 팔 동작의 기구학 및 동역학적 분석 - 파트 2: 제한조건의 선형 결합)

  • Kim, Hyunchul;Lee, Choon-Young
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.8
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    • pp.875-881
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    • 2014
  • The redundancy resolution of the seven DOF (Degree of Freedom) upper limb exoskeleton is key to the synchronous motion between a robot and a human user. According to the seven DOF human arm model, positioning and orientating the wrist can be completed by multiple arm configurations that results in the non-unique solution to the inverse kinematics. This paper presents analysis on the kinematic and dynamic aspect of the human arm movement and its effect on the redundancy resolution of the seven DOF human arm model. The redundancy of the arm is expressed mathematically by defining the swivel angle. The final form of swivel angle can be represented as a linear combination of two different swivel angles achieved by optimizing two cost functions based on kinematic and dynamic criteria. The kinematic criterion is to maximize the projection of the longest principal axis of the manipulability ellipsoid of the human arm on the vector connecting the wrist and the virtual target on the head region. The dynamic criterion is to minimize the mechanical work done in the joint space for each of two consecutive points along the task space trajectory. The contribution of each criterion on the redundancy was verified by the post processing of experimental data collected with a motion capture system. Results indicate that the bimodal redundancy resolution approach improved the accuracy of the predicted swivel angle. Statistical testing of the dynamic constraint contribution shows that under moderate speeds and no load, the dynamic component of the human arm is not dominant, and it is enough to resolve the redundancy without dynamic constraint for the realtime application.

Inertia Property-Based Redundancy Resolution in Posture Control of Mobile Manipulator

  • Kang, Sungchul;Komoriya, Kiyoshi;Yokoi, Kazuhito;Koutoku, Tetsuo;Tanie, Kazuo
    • 제어로봇시스템학회:학술대회논문집
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    • pp.155.4-155
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    • 2001
  • This paper deals with the inertia property-based redundancy resolution in posture control of a mobile manipulator. As a measure for the redundancy resolution of a mobile manipulator, an effective inertia at the end effector in the operational space is proposed and investigated. The reduced effective inertia has a significant effect on reducing the impulse force in collision with environment. To find a posture satisfying both the reduced inertia and joint limit constraints, we propose a combined potential function method that can deal with multiple constraints. The proposed reduced inertia property algorithm is integrated into a damping controller to reduce the impulse force at collision and to regulate the contact force in mobile manipulation ...

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Redundancy Resolution for Free-Floating Manipulators Using Kinematic Optimal Control Approach (기구학적 최적 제어를 사용한 자유 부유 매니퓰레이터의 여유도 해결)

  • Kim, Yong-Min;Kim, Byung-Kook
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.8
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    • pp.790-798
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    • 2011
  • An efficient sequential computation algorithm of kinematic optimal control is suggested for redundancy resolution of freefloating manipulators. Utilization of minimum principle usually requires involved and tedious procedure of differentiation of Hamiltonian. Due to the constraints of momentum conservation, it is not easy to get exact differential equations of boundary value problem for even relatively simple free-floating manipulator models. To overcome this difficulty, we developed an effective sequential algorithm for the computation of terms appeared in the differential equations. The usefulness of suggested approach is verified by simulation of a planar 3-joints free-floating manipulator.

Redundancy resolution method of omni-directional mobile manipulator system (전방향 이동 머니퓰레이터 시스템의 여유자유도 최적화 방법)

  • Kwon, Soon-Jae;Jeong, Jae-Ung
    • Journal of the Korea Society For Power System Engineering
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    • v.19 no.3
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    • pp.75-80
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    • 2015
  • Typically, robot system configured by articulated robot manipulator with 1 DOF transfer unit is being applied in automotive manufacturing automation process. Especially, 1 DOF transfer unit is necessary to extend workspace of robot manipulator. In this configuration, because transfer unit works only one direction, robot manipulator only works in one side in case of car body painting or sealing automation process. it is necessary three robot manipulator system at least. In this paper, in order to robot manipulator works effectively in car body sealing automation application, we are suggested omni-directional manipulator system and conducted studying on redundancy resolution method to solve manipulability-optimal problem.

Natural Resolution of DOF Redundancy in Execution of Robot Tasks;Stability on a Constraint Manifold

  • Arimoto, S.;Hashiguchi, H.;Bae, J.H.
    • 제어로봇시스템학회:학술대회논문집
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    • pp.180-185
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    • 2003
  • In order to enhance dexterity in execution of robot tasks, a redundant number of degrees-of-freedom (DOF) is adopted for design of robotic mechanisms like robot arms and multi-fingered robot hands. Associated with such redundancy in the number of DOFs relative to the number of physical variables necessary and sufficient for description of a given task, an extra performance index is introduced for controlling such a redundant robot in order to avoid arising of an ill-posed problem of inverse kinematics from the task space to the joint space. This paper shows that such an ill-posedness of DOF redundancy can be resolved in a natural way by using a novel concept named “stability on a manifold”. To show this, two illustrative robot tasks 1) robotic handwriting and 2) control of an object posture via rolling contact by a multi-DOF finger are analyzed in details.

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