• Title/Summary/Keyword: robot systems

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A Performance Improvement for Tracking Controller of a Mobile Robot Using Neural Networks (신경망을 이용한 이동로봇 궤적제어기 성능개선)

  • Park Jae-Hwae;Lee Man-Hyung;Lee JangMyung
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.12
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    • pp.1249-1255
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    • 2004
  • A new parameter adaptation scheme for RBF Neural Network (NN) has been developed in this paper. Even though the RBF Neural Network (NN) based controllers are robust against both un-modeled dynamics and external disturbances, the performance is not satisfactory for a fast and precise mobile robot. To improve the tracking performance as well as robustness, all the parameters of RBF NN are updated in real time. The stability of this control law is rigorously proved by following the Lyapunov stability theory and shown by the experimental simulations. The fact that all of the weighting factors, width and center of RBF NN have been updated implies that this scheme utilizes all the possibilities in RBF NN to make the controller robust and precise while the mobile robot is following un-known trajectories. The performance of this new algorithm has been compared to the conventional RBF NN controller where some of the parameters are adjusted for robustness.

Development of vision-based soccer robots for multi-agent cooperative systems (다개체 협력 시스템을 위한 비젼 기반 축구 로봇 시스템의 개발)

  • 심현식;정명진;최인환;김종환
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.608-611
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    • 1997
  • The soccer robot system consists of multi agents, with highly coordinated operation and movements so as to fulfill specific objectives, even under adverse situation. The coordination of the multi-agents is associated with a lot of supplementary work in advance. The associated issues are the position correction, prevention of communication congestion, local information sensing in addition to the need for imitating the human-like decision making. A control structure for soccer robot is designed and several behaviors and actions for a soccer robot are proposed. Variable zone defense as a basic strategy and several special strategies for fouls are applied to SOTY2 team.

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Distance Error Compensation of Direct Control Type Internet-based Mobile Robot System (직접명령 방식 인터넷 주행로봇 시스템의 거리 오차 보상)

  • 이강희;김수현;곽윤근
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.3
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    • pp.273-279
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    • 2004
  • This research is concerned with the development of an Internet-based robot system, which is insensitive to the unpredictable internet time delay. For this purpose, a simple mobile robot system that moves in response to the user s direct control on the internet has been developed. The time delay in data transmission is an important problem for the construction of this kind of system. Therefore, the PPS (Position Prediction Simulator) is suggested and implemented to compensate for the time delay problem of the internet. The simulation and experimental results show that the distance error can be reduced using the developed PPS.

Robust Control of a Haptic Interface Using LQG/LTR (LQG/LTR을 이용한 Haptic Interface의 강인제어)

  • Lee, Sang-Cheol;Park, Heon;Lee, Su-Sung;Lee, Jang-Myung
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.9
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    • pp.757-763
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    • 2002
  • A newly designed haptic interface enables an operator to control a remote robot precisely. It transmits position information to the remote robot and feeds back the interaction force from it. A control algorithm of haptic interface has been studied to improve the robustness and stability to uncertain dynamic environments with a proposed contact dynamic model that incorporates human hand dynamics. A simplified hybrid parallel robot dynamic model fur a 6 DOF haptic device was proposed to from a real time control system, which does not include nonlinear components. LQC/LTR scheme was adopted in this paper for the compensation of un-modeled dynamics. The recovery of the farce from the remote robot at the haptic interface was demonstrated through the experiments.

Trajectory Control of Field Robot Using Adaptive Control and System Identification (적응제어 및 시스템 규명을 이용한 Field Robot의 궤적 제어)

  • Kim, Seung-Su;Seo, U-Seok;Yang, Sun-Yong;Lee, Byeong-Ryong;An, Gyeong-Gwan
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.9
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    • pp.728-735
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    • 2002
  • The Field robot means the machinery applied for outdoor tasks in construction, agriculture and undersea etc. In this study, to field-robotize a hydraulic excavator that is mostly used in construction working, we have developed an automatic excavation system and an adaptive control system. A model-reference adaptive controller has been designed based on the model that is obtained through off-line system identification. It is illustrated by computer simulations that the proposed control system gives good performance in the trajectory tracking control and the adaptation to parameter variation.

Robust Fault-Tolerant Control for a Robot System Anticipating Joint Failures in the Presence of Uncertainties (불확실성의 존재에서 관절 고장을 가지는 로봇 시스템에 대한 강인한 내고장 제어)

  • 신진호
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.10
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    • pp.755-767
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    • 2003
  • This paper proposes a robust fault-tolerant control framework for robot manipulators to maintain the required performance and achieve task completion in the presence of both partial joint failures and complete joint failures and uncertainties. In the case of a complete joint failure or free-swinging joint failure causing the complete loss of torque on a joint, a fully-actuated robot manipulator can be viewed as an underactuated robot manipulator. To detect and identify a complete actuator failure, an on-line fault detection operation is also presented. The proposed fault-tolerant control system contains a robust adaptive controller overcoming partial joint failures based on robust adaptive control methodology, an on-line fault detector detecting and identifying complete joint failures, and a robust adaptive controller overcoming partial and complete joint failures, and so eventually it can face and overcome joint failures and uncertainties. Numerical simulations are conducted to validate the proposed robust fault-tolerant control scheme.

Detection of Absolute Position of Robot Joint Using Incremental Encoders (증분형 엔코더를 이용한 로봇 관절의 절대위치 검출)

  • Lim, Jae Sik;Lee, Young Jin
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.6
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    • pp.577-582
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    • 2015
  • This paper proposes an efficient detection of absolute position of a robot joint using two incremental encoders. We considers a robot joint comprising a motor, a reducer, two encoders, and a motor drive. An incremental(first) encoder provides motor's rotor position or input position of reducer while another incremental(second) encoder does output position of the reducer. A table is made where the relationship between the first and the second encoder counts is recorded. The key point is placed where the table is constructed: when a pulse occurs in the second encoder, there exists a corresponding unique count value of the first encoder. The absolute position is detected using the table by searching the second encoder position corresponding to the first encoder count value when a pulse occurs in the second encoder. The proposed method needs a small rotation, as just one second encoder's pulse angle, for the initial absolute position detection.

H Observer Design for Detecting Internal Oil Leakage in a Hydraulic Cylinder (유압실린더 내부 누유 검출을 위한 H 관측기 설계)

  • Jee, Sung Chul;Kang, Hyungjoo;Lee, Mun-Jik;Li, Ji-Hong
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.2
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    • pp.117-125
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    • 2016
  • This paper presents the internal oil leakage detection problem for a hydraulic double-rod cylinder. We represent the dynamics of the hydraulic cylinder as a convex combination of linear equations. To detect oil leakage, we propose a model-based fault detection observer design scheme. The observer is designed to be robust against disturbance. Sufficient design conditions are derived in the form of linear matrix inequalities. A numerical example is provided to verify the proposed techniques.

Development of Autonomous Navigation Robot in Outdoor Road Environments (실외 도로 환경에서의 자율주행 로봇 개발)

  • Roh, Chi-Won;Kang, Yeon-Sik;Kang, Sung-Chul
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.3
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    • pp.293-299
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    • 2009
  • This paper discusses an autonomous navigation system for urban environments. For the localization of the robot, EKF (Extended Kalman Filter) algorithm is used with odometry, angle sensor, and DGPS (Differential Global Positioning System) measurement. Especially in an urban environment, DGPS is often blocked by buildings and trees and the resulting inaccurate positioning prevents the robot from safe and reliable navigation. In addition to the global information from DGPS, the local information of the curb on the roadway is used to track a route when the global DGPS information is inaccurate. For this purpose, curb detection algorithm is developed and implemented in the developed navigation algorithm. Four different types of navigation strategies are developed and they are switched to adapt to different localization conditions according to the availability of DGPS and the existence of the curbs on the roadway. The experimental results show that the designed switching strategy improves the navigation performance adapting to the environment conditions.

Optimal Design and Simulation of SCARA Robot Arm (스카라 로봇 암의 최적화 설계 및 시뮬레이션)

  • Lee, Jong-Shin
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.6
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    • pp.612-618
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    • 2009
  • This study is concerned about the optimal design of the arm 1 and arm 2 in the SCARA robot. The mass and inertia moment of the arm I and arm 2 in a SCARA robot is greatly affected on the performance such as a cycle time, and torques loaded on $1^{st}$ axis and $2^{nd}$ axis. To reduce the mass and inertia moment, this study carried out optimal design by FEM analysis using parametric variables, which is a width, a height of the rib and a thickness of arm in the arm. The rib is adapted instead of reducing the thickness in the arm. And the simulation by computer was conducted on two given paths in X direction and Y direction. After optimal design, the result showed that maximum torque of $1^{st}$ axis and $2^{nd}$ axis reduced to maximum 9.5% on a given path.