• Title/Summary/Keyword: Robot manipulators

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Robust Decentralized Adaptive Controller for Trajectory Tracking Control of Uncertain Robotic Manipulators (비중앙 집중식 강성 적응 제어법을 통한 산업용 로봇 궤도추적제어)

  • 유삼상
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.30 no.4
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    • pp.329-340
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    • 1994
  • This paper presents a dynamic compensation methodology for robust trajectory tracking control of uncertain robot manipulators. To improve tracking performance of the system, a full model-based feedforward compensation with continuous VS-type robust control is developed in this paper(i.e,. robust decentralized adaptive control scheme). Since possible bounds of uncertainties are unknown, the adaptive bounds of the robust control is used to directly estimate the uncertainty bounds(instead of estimating manipulator parameters as in centralized adaptive control0. The global stability and robustness issues of the proposed control algorithm have been investigated extensively and rigorously via a Lyapunov method. The presented control algorithm guarantees that all system responses are uniformly ultimately bounded. Thus, it is shown that the control system is evaluated to be highly robust with respect to significant uncertainties.

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Robust Tracking Control of Robotic Manipulators Using Fuzzy-Sliding Modes (퍼지-슬라이딩모드를 이용한 로봇의 강건추적제어)

  • 김정식;최승복
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.8
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    • pp.2088-2100
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    • 1994
  • Considerable attention has been given to controller designs that utilize the variable structure system theory in order to achieve robust tracking performance of robotic manipulators subjected to parameter variations and extraneous disturbances. However, the theory has not had wide spread acceptance in practical control engineering community due mainly to the worry of chattering which is inherently ever-existing in the variable structure system. This paper presents a novel type of fuzzy-sliding mode controller to alleviate the chattering problem. A sliding mode controller for robust robot control is firstly synthesized with an assumption that the imposed system uncertainties satisfy matching conditions so that certain deterministic performances can parameters and control rules are obtained from a relation between predetermined sliding surfaces and representative points in the error state space. A two degree-of-freedom robotic manipulator subjected to a variable payload and a torque disturbance is considered in order to demonstrate superior tracking performance accrued from the proposed methodology.

Fuzzy Control Algorithm Eliminating Steady-state Position Errors of Robotic Manipulators (로봇 머니퓰레이터의 정상상태 위치오차를 제거할 수 있는 퍼지제어 알고리듬)

  • Kang, Chul-Goo;Kwak, Hee-Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.3
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    • pp.361-368
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    • 1997
  • In order to eliminate position errors existing at the steady state in the motion control of robotic manipulators, a new fuzzy control algorithm is propeosed using three variables, position error, velocity error and integral of position errors as input variables of the fuzzy controller. Although the number of input variables of the fuzzy controller is increased from two to three, the number of fuzzy control rules is just increased by two. Three dimensional look-up table is used to reduce the computational time in real-time control, and a technique reducing the amount of necessary memory is introduced. Simulation and experimental studies show that the position errors at the steady state are decreased more than 90% compared to those of existing fuzzy controller when the proposed fuzzy controller is applied to the 2 axis direct drive SCARA robot manipulator.

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.

Implementation of a real-time neural controller for robotic manipulator using TMS 320C3x chip (TMS320C3x 칩을 이용한 로보트 매뉴퓰레이터의 실시간 신경 제어기 실현)

  • 김용태;한성현
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.65-68
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    • 1996
  • Robotic manipulators have become increasingly important in the field of flexible automation. High speed and high-precision trajectory tracking are indispensable capabilities for their versatile application. The need to meet demanding control requirement in increasingly complex dynamical control systems under significant uncertainties, leads toward design of intelligent manipulation robots. This paper presents a new approach to the design of neural control system using digital signal processors in order to improve the precision and robustness. The TMS32OC31 is used in implementing real time neural control to provide an enhanced motion control for robotic manipulators. In this control scheme, the networks introduced are neural nets with dynamic neurons, whose dynamics are distributed over all the, network nodes. The nets are trained by the distributed dynamic back propagation algorithm. The proposed neural network control scheme is simple in structure, fast in computation, and suitable for implementation of real-time, control. Performance of the neural controller is illustrated by simulation and experimental results for a SCARA robot.

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Near-optimum trajectory planning for robot manipulators

  • Yamamoto, Motoji;Marushima, Shinya;Mohri, Akira
    • 제어로봇시스템학회:학술대회논문집
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    • 1989.10a
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    • pp.621-626
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    • 1989
  • An efficient algorithm for planning near-optimum trajectory of manipulators is proposed. The algorithm is divided into two stages. The first one is the optimization of time trajectory with given spatial path. And the second one is the optimization of the spatial path itself. To consider the second problem, the manipulator dynamics is represented using the path parameter "s", then a differential equation corresponding to the dynamics is solved as two point boundary value problem. In this procedure, the gradient method is used to calculate improved input torques.t torques.

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Dynamic Modeling of Two Cooperating Flexible Manipulators

  • Kim, Jin-Soo;Uchiyama, Masaru
    • Journal of Mechanical Science and Technology
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    • v.14 no.2
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    • pp.188-196
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    • 2000
  • In this paper, our aim is to develop a model for two cooperating flexible manipulators handling a rigid object by using lumped parameters. This model is in turn analyzed on MATLAB. In order to validate the model, a precise simulation model is developed using $ADAMS^{TM}$ (Automatic Dynamic Analysis of Mechanical System). Moreover, to clarify the discussion, the motions of a dual-arm experimental flexible manipulator are considered. Using the developed model, we control a robotic system with a symmetric hybrid position/force control scheme. Finally, experiments and simulations are performed, and a comparison of simulation results with experimental results is given to a rerify the validity of our model.

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Robust Control of Trajectory Tracking for Hydraulic Excavator (유압 굴삭기의 궤적 추종을 위한 강인 제어)

  • 최종환;김승수;양순용;이진걸
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.1
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    • pp.22-29
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    • 2004
  • This paper studies the coordinated trajectory control of an excavator as a kind of robotic manipulators driven by hydraulic actuators. Hydraulic robot system has many non-linearity in dynamics and kinematics, and strong coupling among joints(or hydraulic cylinders). This paper proposes a combined controller frame of the adaptive robust control(ARC) and the sliding mode control(SMC) for the trajectory tracking control of the excavator to preserve the advantages of the both methods while overcoming their drawbacks, namely, asymptotic stability of adaptive system for parametric uncertainties and guaranteed transient performance of sliding mode control for both parametric uncertainties and external disturbance. The suggested control technique is applied for the tracking of a straight-line motion of end-effector of manipulators, and through computer simulations, its trajectory tracking performances and the robustness to payload variation and uncertainties are illustrated.

Obstacle Avoidance of Three-DOE Underactuated Manipulator by Using Switching Computed Torque Method

  • Udawatta, Lanka;Watanabe, Keigo;Izumi, Kiyotaka;Kiguchi, Kazuo
    • Transactions on Control, Automation and Systems Engineering
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    • v.4 no.4
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    • pp.347-355
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    • 2002
  • Obstacle avoidance of underactuated robot manipulators using switching computed torque method (SCTM) is presented. One fundamental feature of this novel method is to use partly stable controllers (PSCs) in order to fulfill the ultimate control objective. Here, we use genetic algorithms (GAs) to acquire the optimum switching sequence of the control actions for a given time frame with the available set of elemental controllers, depending on which links/variables are controlled. The effectiveness of the concept is illustrated by taking a three-degrees-of-freedom (DOF) manipulator and showing enhanced performance of the proposed control methodology.

Adaptive Model Reference Control Based on Takagi-Sugeno Fuzzy Models with Applications to Flexible Joint Manipulators

  • Lee, Jongbae;Lim, Joon-hong;Park, Chang-Woo;Kim, Seungho
    • Journal of Mechanical Science and Technology
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    • v.18 no.3
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    • pp.337-346
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    • 2004
  • The control scheme using fuzzy modeling and Parallel Distributed Compensation (PDC) concept is proposed to provide asymptotic tracking of a reference signal for the flexible joint manipulators with uncertain parameters. From Lyapunov stability analysis and simulation results, the developed control law and adaptive law guarantee the boundedness of all signals in the closed-loop multi-input/multi-output system. In addition, the plant state tracks the state of the reference model asymptotically with time for any bounded reference input signal.