• Proceedings of the KIEE Conference
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.163-168
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• 2002

The voting algorithm for action selection performs self-improvement by Reinforcement learning algorithm in the dynamic environment. The proposed voting algorithm improves the navigation of the robot by adapting the eligibility of the behaviors and determining the Command Set Generator (CGS). The Navigator that using a proposed voting algorithm corresponds to the CGS for giving the weight values and taking the reward values. It is necessary to decide which Command Set control the mobile robot at given time and to select among the candidate actions. The Command Set was learnt online by means as Q-learning. Action Selector compares Q-values of Navigator with Heterogeneous behaviors. Finally, real-world experimentation was carried out. Results show the good performance for the selection on command set as well as the convergence of Q-value.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제5권4호
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• pp.316-321
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• 2005

We designed and implemented fish robots for various purposes such as autonomous navigation, maneuverability control, posture balancing and improvement of quick turns in a tank of 120 X 120 X 180cm size. Typically, fish robots have 30-50 X 15-25 X 10-20cm dimensions; length, width and height, respectively. It is essential to have the ability of quick and smooth turning to avoid collision with obstacles or walls of the water pool at a close distance. Infrared distance sensors are used to detect obstacles, magneto-resistive sensors are used to read direction information, and a two-axis accelerometer is mounted to compensate output of direction sensors. Because of the swing action of its head due to the tail fin movement, the outputs of an infrared distance sensor contain a huge amount of noise around true distances. With the information from accelerometers and e-compass, much improved distance data can be obtained by fuzzy logic based estimation. Successful swimming and smooth turns without collision demonstrated the effectiveness of the distance estimation.

• The KIPS Transactions:PartA
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• 제16A권1호
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• pp.35-42
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• 2009

This paper proposes a new coverage algorithm for intelligent robot. Many algorithms for improving the performance of coverage have been focused on minimizing the total coverage completion time. However, if one does not have enough time to finish the whole coverage, the optimal path could be different. To tackle this problem, we propose a new coverage algorithm, which we call MaxCoverage algorithm, for covering maximal area within the deadline. The MaxCoverage algorithm decides the navigation flow by greedy algorithm for Set Covering Problem. The experimental results show that the MaxCoverage algorithm performs better than other algorithms for random deadlines.

• Journal of the Korean Institute of Intelligent Systems
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• 제19권5호
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• pp.737-742
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• 2009

The popularity of autonomous mobile robots have been rapidly increasing due to their new emerging application area, from room cleaning, tourist guidance to space explorations. However, the development of a satisfactory control algorithm that will enable the autonomous mobile robots to navigate safely especially in dynamic environments is still an open research problem. In this paper, a newly proposed potential field based control method is implemented, analyzed, and improvements are suggest based on experimental results obtain from computer simulations. The experimental results are presented to show the effectiveness of the behavior-based control using the proposed potential field generation technique.

• Journal of the Society of Naval Architects of Korea
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• 제60권6호
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• pp.406-415
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• 2023

In this study, we focused on developing and verifying ship collision avoidance algorithms using Unity simulator and ROS(Robot Operating System). ROS is used to establish an environment where communication between different operating systems is possible, and a dynamic model of a ship is constructed within Unity simulator. The Lidar data collected in Unity environment is passed to the system based on python through ROS. In the system based on python, control command values were created through the logic of the collision avoidance algorithm using data, and the values were transferred back to Unity to control the movement of the virtual ship. Through the developed simulation system, the reliability of the collision avoidance algorithm of ships with two different forms in an environment similar to the actual physical world was confirmed. As a result, it was confirmed on the simulator that it could be avoided without collision even in an environment with various types of obstacles, and that the avoidance characteristics according to the dynamics of the ship could be analyzed.

• Proceedings of the Korea Information Processing Society Conference
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• 한국정보처리학회 2008년도 춘계학술발표대회
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• pp.526-529
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• 2008

로봇의 응용과 활용분야는 현 산업의 주요 이슈가 되고 있다. 현재 싱글로봇의 효율적인 운용을 넘어 전체적인 공간탐색 효율 극대화와 넓은 공간에서 싱글 로봇간의 중복적인 공간 탐색을 최소화하기 위한 자동화된 멀티 로봇 운용 기법은 중요한 연구 주제로 부각되고 있다. 멀티 로봇을 효율적으로 운용하기 위해서는 멀티 로봇 시스템의 각 싱글 로봇의 움직임을 파악하여 효율적으로 업무를 할당 할 수 있는 관리체계가 필요하다. 멀티 로봇의 업무 할당과 중복 탐색 최소화를 위해 본 논문에서는 홈로봇(home robot)과 RFID 시스템을 이용한 멀티 로봇 운영 기법을 제안한다. 제안한 시스템은 로봇들의 Localization, Navigation 및 Mapping을 효율적으로 수행하기 위해 RFID를 활용하고 최적의 공간 할당을 위하여 홈로봇이 각각의 싱글 로봇을 효율적으로 관리한다. 제안된 멀티 로봇 시스템은 싱글 로봇 시스템과 비교하여 시스템 운영의 효율을 극대화할 수 있을 뿐만 아니라 각 싱글 로봇의 상태와 주변 상태를 고려한 fault-tolerance를 제공함으로써 로봇 운용의 신뢰성을 보장할 수 있다. 또한 시뮬레이션을 통해 제안한 시스템과 기존 시스템들을 비교하고 제안한 시스템의 효율성을 입증하였다.

• Journal of Institute of Control, Robotics and Systems
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• 제19권2호
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• pp.158-163
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• 2013

The fusion of the GPS (Global Positioning System) and DR (Dead Reckoning) is widely used for position and latitude estimation of vehicles such as a mobile robot, aerial vehicle and marine vehicle. Among the many types of aerial vehicles, grater focus is given on the quad-rotor and accuracy of the position information is becoming more important. In order to exactly estimate the position information, we propose the fusion method of GPS and Gyroscope sensor using the DEKF (Dual Extended Kalman Filter). The DEKF has an advantage of simultaneously estimating state value and a parameter of dynamical system. It can also be used even if state value is not available. In order to analyze the performance of DEKF, the computer simulation for estimating the position, the velocity and the angle in a circle trajectory of quad-rotor was done. As it can be seen from the simulation results using own proposed DEKF instead of EKF on own fusion method in the navigation of a quad-rotor gave better performance values.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.677-680
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• 2003

Perceptual landmarks are an effective solution for a mobile robot realizing steady and reliable long distance navigation. But the prerequisite is those landmarks must be detected and recognized robustly at a higher speed under various lighting conditions. This made image processing more complicated so that its speed and reliability can not be both satisfied at the same time. Color based target detection technique can separate target color regions from non-target color regions in an image with a faster speed, and better results were obtained only under good lighting conditions. Moreover, in the case that there are other things with a target color, we have to consider other target features to tell apart the target from them. Such thing always happens when we detect a target with its single character. On the other hand, we can generally search for only one target for each time so that we can not make use of landmarks efficiently, especially when we want to make more landmarks work together. In this paper, by making use of the moment invariants of each landmark, we can not only search specified target from separated color region but also find multi-target at the same time if necessary. This made the finite landmarks carry on more functions. Because moment invariants were easily used with some low level image processing techniques, such as color based target detection and gradient runs based target detection etc, and moment invariants are more reliable features of each target, the ratio of target detection were improved. Some necessary experiments were carried on to verify its robustness and efficiency of this method.

• Journal of Advanced Navigation Technology
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• 제15권5호
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• pp.729-734
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• 2011

In this paper, e-Meters middleware and applications using standardized middleware in the EPCglobal is suggested. An standardized middleware of the EPCglobal is designed to manage as a form of SCM and other logistics. In order to support a variety of services using RFID-based, the system must be able to support each protocol. The main features of e-Meters middleware is consist of information status and delivery, distributed database processing, event data analysis, and handling. To operate real time e-Meters system information, The realized middleware is configured to process the results of data collection.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.207-217
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• 2000

In this paper, we describe an image processing algorithm which is able to recognize the road lane. This algorithm performs to recognize the interrelation between AGV and the other vehicle. We experimented on AGV driving test with color CCD camera which is setup on the top of vehicle and acquires the digital signal. This paper is composed of two parts. One is image preprocessing part to measure the condition of the lane and vehicle. This finds the information of lines using RGB ratio cutting algorithm, the edge detection and Hough transform. The other obtains the situation of other vehicles using the image processing and viewport. At first, 2 dimension image information derived from vision sensor is interpreted to the 3 dimension information by the angle and position of the CCD camera. Through these processes, if vehicle knows the driving conditions which are angle, distance error and real position of other vehicles, we should calculate the reference steering angle.