• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1577-1585
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• 2011

This paper proposes a posture stabilization control algorithm for a wheeled mobile robot using hybrid visual servo control method with a position based and an image based visual servoing (PBVS and IBVS). To overcome chattering phenomena which were shown in the previous researches using a simple switching function based on a threshold, the proposed hybrid visual servo control law introduces the fusion function based on a blending function. Then, the chattering problem and rapid motion of the mobile robot can be eliminated. Also, we consider the nonlinearity of the wheeled mobile robot unlike the previous visual servo control laws using linear control methods to improve the performances of the visual servo control law. The proposed posture stabilization control law using hybrid visual servoing is verified by a theoretical analysis and simulation and experimental results.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.9
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• pp.834-838
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• 2013

This paper proposes a new ball robot which has a four axis structure and four motors that directly actuate the ball to move or to maintain the balance of the robot. For the Balancing control, it is possible to use non-model-based controller to control simply without complex formula. All the gains of the controller are heuristically adjusted during the experiments. The tilt angle is measured by IMU sensors, which is used to generate the control input of the roll and pitch controller to make the tilt angle zero. The performance of the designed control system has been verified through the real experiments with the developed ball robot.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.4
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• pp.359-365
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• 2011

A mobile surveillance robot is defined as a surveillance robot system that is mounted on a mobile platform and is used to protect public areas such as airports or harbors from invaders. The mobile surveillance robot that is mounted on a mobile platform consists of a gun module, a camera system module, an embedded control system, and AHRS (Attitude and Heading Reference System). It has two axis control systems for controlling its elevation and azimuth. In order to obtain stable images for targeting invaders, this system requires a stabilizer to compensate any disturbance due to vehicle motion. In this study, a virtual model of a mobile surveillance robot has been created and ADAMS/Matlab simulations have been performed to verify the suitability of the proposed stabilization algorithm. Further, the suitability of the stabilization algorithm has also been verified using a mock-up of the mobile surveillance robot and a 6-DOF (Degree Of Freedom) motion simulator.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.7
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• pp.653-660
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• 2015

This paper describes the design of the force measuring system for an industrial robot's deburring work. The force measuring system is composed of a three-axis force sensor, a measuring device, a housing and a cover. The three-axis force sensor can detect x-direction force, y-direction force and z-direction force at the same time. The measuring device is designed using DSP(Digital Signal Processor), and have a RS-232 and a RS-485 communication port for sending force data to PC or other controller. As a result of test, the repeatability error and the non-lineality error of the three-axis force sensor are less than 0.03%, and the interference error of the sensor is less than 0.95%. It is thought that the force measuring system can be used for an industrial robot's deburring work.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1327-1330
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• 2004

An underwater robotic system has been developed and applied to visual inspection of reactor vessel internals. The Korea Electric Power Robot for Visual Test (KeproVt) consists of an underwater robot, a vision processor-based measuring unit, a master control station and a servo control station. The robot guided by the control station with the measuring unit can be controlled to have any motion at any position in the reactor vessel with $\pm$1 cm positioning and $\pm$2 degrees heading accuracies with enough precision to inspect reactor internals. A simple and fast installation process is emphasized in the developed system. The developed robotic system was successfully deployed at the Younggwang Nuclear Unit 1 for the visual inspection of reactor internals.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.1
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• pp.67-76
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• 2005

In this paper, An analysis on the intelligence system for a biped walking robot(BWR) was made and its results were applied to the BWR. Various sensors were applied to the developed BWR for autonomous and intelligent walk in unknown environments. To measure the distance between the object and BWR, ultrasonic sensor and infrared-rays sensor were used. To identity surrounding environments, vision system was used. Gyro sensor was used to control the posture of BWR. Also, piezoelectricity sensor was used to identity the pressure of foot landing on the surface. Sensors applied to the robot have measurement errors according to noises or walking environments. To improve the function of these sensors, influences of noise or sensing errors were minimized using a sensor fusion scheme. A gait test using the sensor fusion system was performed, and its results are presented.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.810-815
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• 2003

This research is concerned with the development of an Internet-based robot system, which is insensitive to the unpredictable Internet time delay. For that purpose, a simple mobile robot system that moves in response to the user' direct control on the Internet has been built. The time delay in data transmission is a big 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 result show that the distance error can be reduced using the developed PPS.

• Journal of Navigation and Port Research
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• v.33 no.5
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• pp.323-330
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• 2009

We have been developing an underwater robot for harbour construction using a parallel mechanism The robot is attached to the rope of a crane, which curries a large stone into the undersea The robot's yaw and pitch are controlled by hydraulic cylinders but its roll is uncontrollable. We mount propellers in both side of the robot to generate the roll motion This paper studies on the control for the roll motion of a underwater robot. A gyro-sensor is used to measure the angle in a roll motion We develop the dynamic model to describe the robot's roll motion by a second order non-linear system and identify the model parameters by recursive least square and adaptive identifier. PD control, recursive model based control and adaptive model based control are applied with the dynamic model which computes the control input to compensate disturbances. This paper introduces the underwater robot system and presents the simulated and experimental results of the proposed controller.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.2
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• pp.88-92
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• 2011

This paper looks at the development of the visual system of robots, and the development of image processing algorism to measure the size of an object and the distance from robot to an object for the visual system. Robots usually get the visual systems with a camera for measuring the size of an object and the distance to an object. The visual systems are accurately impossible the size and distance in case of that the locations of the systems is changed and the objects are not on the ground. Thus, in this paper, we developed robot's visual system to measure the size of an object and the distance to an object using two cameras and two-degree robot mechanism. And, we developed the image processing algorism to measure the size of an object and the distance from robot to an object for the visual system, and finally, carried out the characteristics test of the developed visual system. As a result, it is thought that the developed system could accurately measure the size of an object and the distance to an object.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.4
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• pp.371-376
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• 2007

This paper presents an emotion recognition and its expression system of an intelligent robot like a home robot or a service robot. Emotion recognition method in the robot is used by a facial image. We use a motion and a position of many facial features. apply a tracking algorithm to recognize a moving user in the mobile robot and eliminate a skin color of a hand and a background without a facial region by using the facial region detecting algorithm in objecting user image. After normalizer operations are the image enlarge or reduction by distance of the detecting facial region and the image revolution transformation by an angel of a face, the mobile robot can object the facial image of a fixing size. And materialize a multi feature selection algorithm to enable robot to recognize an emotion of user. In this paper, used a multi layer perceptron of Artificial Neural Network(ANN) as a pattern recognition art, and a Back Propagation(BP) algorithm as a learning algorithm. Emotion of user that robot recognized is expressed as a graphic LCD. At this time, change two coordinates as the number of times of emotion expressed in ANN, and change a parameter of facial elements(eyes, eyebrows, mouth) as the change of two coordinates. By materializing the system, expressed the complex emotion of human as the avatar of LCD.