• Title/Summary/Keyword: Flexible Control

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Control Design for Flexible Joint Manipulators with Mismatched Uncertainty : Adaptive Robust Scheme

  • Kim, Dong-Hwa
    • Transactions on Control, Automation and Systems Engineering
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    • v.1 no.1
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    • pp.32-43
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    • 1999
  • Adaptive robust control scheme is introduced for flexible joint manipulator with nonlinearities and uncertainties. The system does not satisfy the matching condition due to insufficient actuators for each node. The control only relies on the assumption that the bound of uncertainty exists. Thus, the bounded value does not need to be known a prior. The control utilizes the update law by estimating the bound of the uncertainties. The control scheme uses the backstepping method and constructs a state transformation. Also, stability analysis is done for both transformed system and original system.

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Tip position control of translational 1-link flexible arm with tip mass (Tip mass를 갖는 병진운동 1-링크 탄성암 선단의 위치제어)

  • 이영춘;방두열;이성철
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.1036-1041
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    • 1993
  • The tip of the flexible robot arm has to be controlled by the active control reducing vibration because it has residual vibration after getting to desired position. This paper presents an end-point position control of a 1-link flexible robot arm having tip mass by the PID control algorithm. The system is composed of a flexible arm with tip mass, dc servomotor and ballscrew mechanism under translational motion. The feedback signal composed of the tip displacement measured by laser sensor, estimated velocity and acceleration is used to control the base motion. Theoretical results are obtained by applying the Laplace transform and the numerical inversion method to the governing equations. After the flexible robot arm reaches to. the desired position, the residual vibration is controlled by the PID algorithm. This paper gives the simulation and experimental results of end-point responses according to changing tip-mass and arm length. And this algorithm shows good effects of reducing the residual vibration. Approximately, theoretical response is in good agreement with experimental one.

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Trajectory control of a flexible robot arm using inverse dynamics

  • Sasaki, Minoru;Yamagata, Eiji;Inooka, Hikaru
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10b
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    • pp.987-992
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    • 1988
  • In recent years there has been much interest in using light-weight, higher performance arms for both commercial and space-based applications, leading to the research of flexible robot manipulator. This paper is concerned with the trajectory control of a flexible arm using inverse dynamics. Inverse problems are important to robot control and programming, since they allow one to find the appropriate inputs necessary for producing the desired outputs. The input is obtained by the numerical inversion of Laplace transformation in the time domain. And we attempt the trajectory control experiment of a flexible arm using this calculated input. In this article we compare the numerical results with experimental results and can find good agreement. The results make clear that this technique has the good potential for the control of tip trajectory of flexible robot arms.

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Spillover Suppression in a Flexible Structure using Eigenstructure Assignment (고유구조지정법을 이용한 유연구조물의 스필오버억제)

  • Park, Un-Sik;Choi, Jae-Weon
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.499-504
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    • 2000
  • Since large space structures(LSS) such as a space station, a solar power station satellite, etc., are theoretically distributed parameter and infinite-dimensional system, they have to be modeled into large finite-dimensional systems for control system design. Besides, there are fundamental problems in active vibration control of the large flexible structures. For example, a modeled large finite-dimensional system must be controlled with a much smaller dimensional controller. This causes the spillover phenomenon which degrades the control performances and reduces the stability margin. Furthermore, it may destabilize the entire feedback control system. In this paper, we proposed a novel control method for spillover suppression in the control of large flexible structures by using eigenstructure assignment. Its effectiveness in spillover suppression is investigated and verified by the numerical experiments using an example of the simply supported flexible beam which is modeled to have four controlled modes and eight uncontrolled modes.

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Active Vibration Control of Flexible Cantilever Beam by Intelligent Control Technique (지능제어 기법에 의한 유연 외팔보의 능동 진동제어)

  • Shin, J.;Park, S. H.;Oh, J. E.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.2
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    • pp.205-212
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    • 1997
  • In this study, active vibration control for a flexible cantilever beam was performed by using the intelligent control technique. The intelligent control method which integrating the back propagation algorithm and the fuzzy inference technique was proposed and its performance was examined. The proposed control algorithm for the flexible cantilever beam was verified via computer simulation of active vibration control. Furthermore, the control system and its efficiency were investigated via experiments on active vibration control by the intelligent control technique without a digital signal processing device.

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The Control of Flexible Beam using Nonlinear Compensator with Dual-Input Describing Function (쌍입력 기술함수를 갖는 비선형 보상기를 이용한 유연한 빔의 제어)

  • 권세현;이형기;최부귀
    • Journal of Institute of Control, Robotics and Systems
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    • v.4 no.5
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    • pp.644-650
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    • 1998
  • In this paper , a state space model for flexible beam is presented using the assumed-modes approach. The state space equation is derived for a flexible beam in which one end is connected to a motor and is driven by a torque equation and the other end is free. Many of the transfer function proposed thus far use the torque to the flexible beam as the input and the tip deflection of the flexible beam as the output. The Technique for the analysis and synthesis of the dual-input describing function(DIDF) is introduced here and the construction of a non-linear compensator, based on this technique, is proposed. This non-linear compensator, properly connected in the direct path of a closed-loop linear or non-linear control system. The above non-linear network is used to compensate linear and non-linear systems for instability, limit cycles, low speed of response and static accuracy. The effectiveness of the proposed scheme is demonstrated through computer simulation and experimental results.

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Dynamic Characteristic Analysis of a Flexible Beam Actuated by Moving Coil and DC Motor (가동 코일 및 DC Motor로 작동되는 유연한 빔의 운동 특성 해석)

  • Yu, Hwajoon;Jeong, Wontaick;Nam, Yoonsu
    • Journal of Industrial Technology
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    • v.19
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    • pp.15-23
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    • 1999
  • Active damping system is generally used for the vibration suppression and precise motion control for the flexible structure. This application can be easily found on the space structure and driving mechanism of optical storage devices. Although a control system using the flexible structure has many advantages over using rigid mechanism in driving energy saving, system weights, and etc., more complex and precise control strategies are required. A position control system using flexible structure and the concept of active damper is designed and manufactured, which is driven by slide DC motor and moving coil motor located at the tip of the flexible beam. Dynamic characteristics of this system are investigated by analytic and experimental ways. By the comparison of those two results, a nominal reference model for this system is proposed.

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Analysis and Control of the Flexible Multibody System Using MATLAB (MATLAB을 이용한 유연 다물체 시스템의 해석 및 제어)

  • Jung, Sung-Pil;Park, Tae-Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.5
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    • pp.437-443
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    • 2008
  • In this paper, analysis and control of the flexible multibody system using MATLAB is presented. The equations of motion of a flexible body are derived in terms of the modal coordinate. The rigid-flexible multibody dynamic solver is developed. Finite element information required to analyze motion of flexible bodies is imported from ANSYS. The modified finite element data, such as modal mass matrix, modal stiffness matrix and constraint mode shapes, is calculated in the solver. Since the solver is developed using MATLAB, it is very easy to connect with SIMULINK which is widely used to control motion of the multibody system. Several simulations are implemented to verify the developed solver. A control example is carried out and the usefulness of the developed solver is demonstrated.

A Study on End-effector Friction of Constrained Spatial Flexible Manipulator (구속 받는 3차원 유연 매니퓰레이터 선단의 마찰에 관한 연구)

  • Kim, Jin-Soo
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.19 no.4
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    • pp.449-454
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    • 2010
  • The force control of a constrained flexible manipulators has been one of the major research topics. However, a little effort has been devoted for the relation between friction force and elastic deflection of end-effector for a constrained flexible manipulator. So, the aim of this paper is to clarify the friction mechanism of a constrained spatial multi-link flexible manipulator by changing the material and connected method of end-effector. In this study, a concise hybrid position/force control scheme is applied to the control of a flexible manipulator, and the experimental results for the constrained vertical motion and constrained horizontal motion is presented. Finally a comparison between these results are presented to show the reduction of vibration of link and friction force.

The vibration control of Flexible Manipulator using Parallel Fuzzy controller and Reference Trajectory Command (병렬퍼지 제어기와 기준궤적신호를 이용한 유연한 매니퓰레이터의 진동제어)

  • 박양수;박윤명
    • Journal of the Institute of Convergence Signal Processing
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    • v.3 no.1
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    • pp.61-66
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    • 2002
  • A fuzzy control strategy is described which is utilized to control the joint angle and tip deflection in single flexible manipulator. In this paper, an existing model for a single flexible manipulator is used for the initial development of an FLC. One FLC is designed to govern the joint angle of the manipulator as it is rotated from one position to another, and the second FLC is designed to attenuate the tip deflection which result from joint angle body motion. Reference Trajectory Command is an important method to reduce vibration in flexible beam. This paper presents a very simple command control shaping which eliminates multiple mode residual vibration in a flexible beam combined parallel fuzzy controller. The effectiveness of proposed scheme is demonstrated through computer simulation.

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