• Title/Summary/Keyword: Robot Actuator

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Development of a Snake Robot with 2-DOF Actuator Modules (2 자유도 작동기 모듈로 구성된 뱀 로봇 개발)

  • Shin, Ho-Cheol;Jeong, Kyung-Min;Kwon, Jeong-Joo
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.7
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    • pp.697-703
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    • 2011
  • This article describes a snake robot with 2-DOF actuator modules. The 2-DOF actuator modules make the snake robot move in the 3D space so that the snake robot can cross obstacles and rough terrain. Each 2-DOF actuator module is designed to have high torque output and an embedded controller. A cross bracket connecting the modules is designed be able to support the weight of two actuator modules. The developed snake robot shows 3-D motions such as side winding, standing/monitoring, and can climb in a narrow pipe with high torque modules. The snake robot moves fast with passive wheels in a plane while crossing obstacles.

Robust Adaptive Fuzzy Tracking Control Using a FBFN for a Mobile Robot with Actuator Dynamics (구동기 동역학을 가지는 이동 로봇에 대한 FBFN을 이용한 강인 적응 퍼지 추종 제어)

  • Shin, Jin-Ho;Kim, Won-Ho;Lee, Moon-Noh
    • Journal of Institute of Control, Robotics and Systems
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    • v.16 no.4
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    • pp.319-328
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    • 2010
  • This paper proposes a robust adaptive fuzzy tracking control scheme for a nonholonomic mobile robot with external disturbances as well as parameter uncertainties in the robot kinematics, the robot dynamics, and the actuator dynamics. In modeling a mobile robot, the actuator dynamics is integrated with the robot kinematics and dynamics so that the actuator input voltages are the control inputs. The presented controller is designed based on a FBFN (Fuzzy Basis Function Network) to approximate an unknown nonlinear dynamic function with the uncertainties, and a robust adaptive input to overcome the uncertainties. When the controller is designed, the different parameters for two actuator models in the actuator dynamics are taken into account. The proposed control scheme does not require the kinematic and dynamic parameters of the robot and actuators accurately. It can also alleviate the input chattering and overcome the unknown friction force. The stability of the closed-loop control system including the kinematic control system is guaranteed by using the Lyapunov stability theory and the presented adaptive laws. The validity and robustness of the proposed control scheme are shown through a computer simulation.

Development of a New Robot Manipulator Driven by the Closed-chain Actuator (폐체인 구조의 새로운 다관절 로봇 매니퓰레이터 개발)

  • 최형식;백창열
    • Journal of Advanced Marine Engineering and Technology
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    • v.27 no.2
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    • pp.238-245
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    • 2003
  • To overcome the weakness in the load capacity of conventional robot manipulators actuated by motors with the speed reducer such as the harmonic driver, we proposed a new closed-chain type of the robot actuator which is composed of the four-bar-link mechanism driven by the ball screw. The robot manipulator is revolute-jointed and composed of four axes. The base axis is actuated by the lineal actuator such as the ball screw, and the others are actuated by the proposed actuator. We analyzed the mechanism of the actuators of the robot joints, and developed the dynamics model. The dynamics are expressed in the joint coordinates and then they are mapped into the sliding coordinates of the ball screw. We performed fundamental tests on the structure of the robot.

Performance Analysis and Optimal Actuator Sizing for Anthropomorphic Robot Modules with Redundant Actuation (여유구동 인체형 로봇 모듈의 성능해석 및 구동장치 최적설계)

  • 이상헌;이병주;곽윤근
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.1
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    • pp.181-192
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    • 1995
  • In this study, we introduce new types of planar 2 degree-of-freedom robot modules resembling the musculoskeletal structure of the human arm with actuation redundancy. First, for the given actuator sizes the performance analysis for the manipulator with redundant actuation and without redundant actuation is performed with respect to maximum load handling capacity, maximum hand velocity, and maximum hand acceleration. Secondly an algorithm which decides optimal actuator sizes for the given operational performances is introduced, and the optimal actuator sizes for a robot module with four redundant actuation are obtained. The algorithms employed in this paper will be useful to analyze the robot performances and to determine the actuator sizes for general robot manipulators.

Robust Adaptive Fault-Tolerant Control for Robot Manipulators with Performance Degradation Due to Actuator Failures and Uncertainties (구동기 고장과 불확실성으로 인한 성능 저하를 가지는 로봇 매니퓰레이터에 대한 강인한 적응 내고장 제어)

  • 신진호;백운보
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.3
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    • pp.173-181
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    • 2004
  • In normal robot control systems without any actuator failures, it is assumed that actuator torque coefficients applied at each joint have normally 1's all the time. However, it is more practical that actuator torque coefficients applied at each joint are nonlinear time-varying. In other words, it has to be considered that actuators equipped at joints may fail due to hardware or software faults. In this work, actuator torque coefficients are assumed to have non-zero values at all joints. In the case of an actuator torque coefficient which has a zero value at a joint, it means the complete loss of torque on the joint. This paper doesn't deal with the case. As factors of performance degradation of robots, both actuator failures and uncertainties are considered in this paper at the same time. This paper proposes a robust adaptive fault-tolerant control scheme to maintain the required performance and achieve task completion for robot manipulators with performance degradation due to actuator failures and uncertainties. Simulation results are shown to verify the fault tolerance and robustness of the Proposed control scheme.

A Study of Hydraulic Actuator Based On Electro Servo Valve For A Walking Robot (보행 로봇을 위한 서보밸브 구동 유압 액추에이터의 특성 분석)

  • Cho, Jung San
    • Journal of Drive and Control
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    • v.13 no.2
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    • pp.26-33
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    • 2016
  • This paper describes of a mathematical and real experimental analysis for a walking robot which uses servo valve driven hydraulic actuator. Recently, many researchers are developing a walking robot based on hydraulic systems for the difficult and dangerous missions such as walking in the rough terrain and carrying a heavy load. In order to design and control a walking robot, the characteristics of the hydraulic actuators in the joint through the view point of walking such as controllability and backdrivability must be analyzed. A general mathematical model was used for analysis and proceeds to position and pressure changes characteristic of the input and backdrivability experiment. The result shows the actuator is a velocity source, had a high impedance, the output stiffness is high in contact with the rigid external force. So stand above the controller and instruments that complement the design characteristics can be seen the need to apply a hydraulic actuator in walking robot.

Design of the Proprioceptive Actuator Capable of Simultaneous Bidirectional Driving (양방향 동시 구동이 가능한 고유수용성 구동기의 설계)

  • Park, Hui-Chang;Cho, Yong-Jun;Yun, Hae-Yong;Oh, Jang-Seok;Hong, Hyung-Gil;Kang, Min-Su;Park, Kwan-Hyung;Song, Jae-Bok
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.21 no.9
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    • pp.98-104
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    • 2022
  • Because a robot actuator is directly affected by the external force of the robot and accounts for the largest portion of the robot system weight, developing an optimized actuator suitable for each characteristic of the robot system is essential. Although there have been many developments and studies related to robot actuators in various industrial fields, lightweight and compact actuator designs that can control force are still lacking. In this study, a novel actuator module was developed, and its performance was verified experimentally. The structure and control of various robot systems can be optimized by utilizing the proposed actuator. It can be used for various tasks by sensing external force and through feedback control.

A Study on Design of Underactuated Robot Hand driven by Shape Memory Alloy (형상기억합금 Underactuated 로봇 핸드의 설계에 관한 연구)

  • Kim, Gwang-Ho;Shin, Sang-Ho;Jeong, Sang-Hwa
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.5
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    • pp.51-57
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    • 2011
  • The lightweight and compact actuator with high power is required to perform motion with multiple degrees of freedom. To reduce the size and inertia of a robot manipulator, the mechanical transmission system is used. The shape memory alloy(SMA) is similar to the muscle-tendon-bone network of a human hand. However, there are some drawback and nonlinearity, such as the hysteresis and the stress dependence. In this paper, the design of the underactuated robot hand is studied. The 3-finger dexterous hand is driven by the SMA actuator using segmental mechanism. This digital approach enables to overcome the nonlinearity of SMA wire. The translational displacement of SMA actuator required to bend a phalanx of the underactuated robot hand is estimated and the bending angle of the underactuated robot hand according to input displacement of SMA actuator is predicted by the multi-body dynamic analysis.

Hopping Robot Using Direct-drive Method and Thermal Modeling to Analyze Motor Limitation (Direct-drive를 활용한 소형 연속 도약 로봇 및 DC모터의 열 모델을 통한 한계 분석)

  • Myeongjin Jang;Seongyo Yang;Gwang-Pil Jung
    • The Journal of Korea Robotics Society
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    • v.19 no.1
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    • pp.53-57
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    • 2024
  • A hopping robot can move through a confined environment while overcoming obstacles. To create a small hopping robot, it must be able to generate a large amount of energy and release it at the same time. However, due to the small size of the robot, there is a limit to the size of the actuator that can be used, so it is mainly used to collect energy in an elastic element and release it at once. In this paper, we propose a small hopping robot with a simplified design by removing ancillary parts and enabling continuous hopping using only a small actuator based on a direct-drive method. In addition, repeated actuation over the rated voltage can cause thermal breakdown of the actuator. To check the safety of the actuator at high voltage, we perform modeling to predict the temperature of the actuator and verify the accuracy of the modeling through experiments.

Robust Adaptive Fuzzy Backstepping Control for Trajectory Tracking of an Electrically Driven Nonholonomic Mobile Robot with Uncertainties (불확실성을 가지는 전기 구동 논홀로노믹 이동 로봇의 궤적 추종을 위한 강인 적응 퍼지 백스테핑 제어)

  • Shin, Jin-Ho
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.10
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    • pp.902-911
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    • 2012
  • This paper proposes a robust adaptive fuzzy backstepping control scheme for trajectory tracking of an electrically driven nonholonomic mobile robot with uncertainties and actuator dynamics. A complete model of an electrically driven nonholonomic mobile robot described in this work includes all models of the uncertain robot kinematics with a nonholonomic constraint, the uncertain robot body dynamics with uncertain frictions and unmodeled disturbances, and the uncertain actuator dynamics with disturbances. The proposed control scheme uses the backstepping control approach through a kinematic controller and a robust adaptive fuzzy velocity tracking controller. The presented control scheme has a voltage control input with an auxiliary current control input rather than a torque control input. It has two FBFNs(Fuzzy Basis Function Networks) to approximate two unknown nonlinear robot dynamic functions and a robust adaptive control input with the proposed adaptive laws to overcome the uncertainties such as parameter uncertainties and external disturbances. The proposed control scheme does not a priori require the accurate knowledge of all parameters in the robot kinematics, robot dynamics and actuator dynamics. It can also alleviate the chattering of the control input. Using the Lyapunov stability theory, the stability of the closed-loop robot control system is guaranteed. Simulation results show the validity and robustness of the proposed control scheme.