• International Journal of Control, Automation, and Systems
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• v.5 no.3
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• pp.343-348
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• 2007

This paper presents an adaptive controller for the compensation of state-dependent disturbance with unknown amplitude in a digital servo motor system. The state-dependent disturbance is caused by friction and eccentricity between the wheel axis and the motor driver of a mobile robot servo system. The proposed control scheme guarantees an asymptotical stability for both the velocity and position regulation. An experimental result shows the effectiveness of the adaptive disturbance compensator for wheeled-mobile robot in a low velocity diffusion tracking. A comparative experimental study with a simple PI controller is presented.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.155-156
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• 2022

In the process of developing an industrial robot, various simulations should be conducted to evaluate the driving, movement, and performance of the robot. Space and time constraints exist to manufacture existing robots and implement various simulations, and efficiency is reduced due to high costs. To solve this problem, many simulations can be conducted by implementing the same movement and working environment as the real environment in virtual reality using digital twin technology. This study proposes a process for establishing a digital twin model of automated layout robots. Using the digital twin model, it is expected that it will not only evaluate the hardware performance of the robot in the future, but also verify the robot's algorithms such as motion planning and work process, identify and solve potential problems in advance, and prevent problems caused by software.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2162-2167
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• 2014

Robots are widely used in various automation processes in industrial applications. Traditionally, it operated under fixed condition by teaching operating positions. Recently, diverse 2D/3D sensors are used together with robot to give more flexibility in operation. In this paper, we deal with automatic manipulation of tie rod in automotive production line. Sensor system consisted of a camera and slit laser is used for the acquisition of 3D information and it is used attached on the robot. Nut runner is used for the manipulation of stop nut and adjust bolt on the tie rod. Detailed procedures for the automatic manipulation of tie rod are presented. In the presented approach, we effectively use 3D information in whole procedure such as computing distance to the tie rod, rotation angle of bolt and nut. Experimental results show the feasibility of the proposed algorithm.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.7
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• pp.595-601
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• 2005

A mobile robot system utilizing NDT (Non-Destructive Testing) method is designed and fabricated f3r automatic integrity evaluation of large sized industrial reservoirs and pipelines. The developed mobile robot can crawl over the outer surface of the industrial facilities even though the shape of the structures is various and unsymmetric. The robot detects defects such as pinholes, cracks and thickness reduction at the wall of the facilities using EMAT (Electro-Magnetic Acoustic Transducer). Image processing technology for weld line detection at the surface of the target and host programs including defect detecting algorithms are also developed. Automation of defect detection for these kinds of large facilities using mobile robots is helpful to prevent significant troubles of the structures without danger of human beings under harmful environment.

• International Journal of Control, Automation, and Systems
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• v.3 no.1
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• pp.1-14
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• 2005

This paper presents an obstacle detection algorithm based on the consecutive and the cooperative range sensor scanning schemes. For a known environment, a mobile robot scans the surroundings using a range sensor that can rotate 3600°. The environment is rebuilt using nodes of two adjacent walls. The robot configuration is then estimated and an obstacle is detected by comparing characteristic points of the sensor readings. In order to extract edges from noisy and inaccurate sensor readings, a filtering algorithm is developed. For multiple robot localization, a cooperative scanning method with sensor range limit is developed. Both are verified with simulation and experiments.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.3
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• pp.181-190
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• 2015

This paper presents a new approach to control the position of robot arm in workspace a robot manipulator under unknown system parameters and bounded disturbance inputs. To control the motion of the manipulator, an inverse dynamics control scheme was applied. Since parameters of the robot arm such as mass and inertia are not perfectly known, the difference between the actual and estimated parameters was considered as a external disturbance force. To identify the known parameters, an improved robust control algorithm is directly derived from the Lyapunov's Second Method. A robust control algorithm is devised to counteract the bounded disturbance inputs such as contact forces and disturbing forces coming from the difference between the actual and the estimated system parameters. Numerical examples are shown using SCARA arm with four joints.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.132-145
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• 2008

We propose a new technique for autonomous navigation and travelling of mobile robot based on ultrasonic sensors through the narrow labyrinth that leave only distance of a few centimeters on each side between the guides and the robot. In our current implementation the ultrasonic sensor system fires at a rate of 100 ms, that is, each of the 8 sensors fires once during each 100 ms interval. This is a very good firing rate, implemented here for optimal performance. This paper presents an extensively tested and verified solution to the problem of obstacle avoidance. Our solution is based on the optimal placement of ultrasonic sensors at strategic locations around the robot. Both the sensor location and the associated navigation algorithm are defined in such a way that only the accurate radial sonar data is used for accurate travelling.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.430-434
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• 1987

This paper describes implementation of a robot programming system for automation of manufacturing products, which is embedded in the C programming language. World representation and motion primitives necessary to describe a manipulator task are provided by a set of procedure calls and user defined data structures. Off-line programming is implemented with graphic simulation as a debugging tool. PUMA 560 manipulators are used as a model for one task which inserts a nonstandard power IC Iota PCB. Communication facilities are provided for collision avoidance or two manipulators.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1541-1544
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• 1997

The rehailitation robot, one of the service robot, is the important area in the service automation. In the paper, we describe the overall configuration of KARES(KAIST Rehabilitation Engineering System), which is an intellingent rehabilitaion robotic system designed to assist the independent livelihood of the handicapped and the eldrly. KARES consists of the 6 degree of freedom robot arm mounted on a wheelchair, the controller ofr the arm, sensors to perceive environment, and user interface. Basic desired hobs in KARES are gripping the target object and moving it to the user's face for eating, drinking, or cooperation work wiht the mouth. Currently, the manual operation of the arm is available for gripping to target objects. The autonomous functionality will be ginven for the facilities of the human operator.

• The Journal of Korea Robotics Society
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• v.6 no.1
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• pp.49-57
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• 2011

In many industries, the accurate and quick checking of goods in storage is of great importance. Most today's inventory checking is based on bar code scanning, but the relative position between a bar code and an optical scanner should be maintained in close distance and proper angle for the successful scanning. This requirement makes it difficult to fully automate the inventory information/control systems. The use of RFID technology can be a solution for overcoming this problem. The mobile robot presented in this paper is equipped with an RFID tag scanning system, that automates the otherwise manual or semi-automatic inventory checking process. We designed the robot system in a quite practical approach, and the developed system is close to the commercialization stage. In our experiments, the robot could collect information of goods stacked on shelves autonomously without any failure and maintain corresponding database while it navigated predefined paths between the shelves using vision.