• 로봇학회논문지
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• 제9권2호
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• pp.117-123
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• 2014

Localization is one of the essential tasks necessary to achieve autonomous navigation of a mobile robot. One such localization technique, Monte Carlo Localization (MCL) is often applied to a digital surface model. However, there are differences between range data from laser rangefinders and the data predicted using a map. In this study, commonly observed from air and ground (COAG) features and candidate selection based on the shape of sensor data are incorporated to improve localization accuracy. COAG features are used to classify points consistent with both the range sensor data and the predicted data, and the sample candidates are classified according to their shape constructed from sensor data. Comparisons of local tracking and global localization accuracy show the improved accuracy of the proposed method over conventional methods.

• 로봇학회논문지
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• 제3권2호
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• pp.99-105
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• 2008

To achieve autonomous mobile robot navigation, accurate localization technique is the fundamental issue that should be addressed. In augmented reality, the position of a user is required for location-based services. This paper presents indoor localization using infrared reflective artificial landmarks. In order to minimize the disturbance to the user and to provide the ease of installation, the passive landmarks are used. The landmarks are made of coated film which reflects the infrared light efficiently. Infrared light is not visible, but the camera can capture the reflected infrared light. Once the artificial landmark is identified, the camera's relative position/orientation is estimated with respect to the landmark. In order to reduce the number of the required artificial landmarks for a given environment, the pan/tilt mechanism is developed together with the distortion correction algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2503-2506
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• 2002

본 논문에서는 청소로봇의 주행에 관해 연구되어지고 있는 이론적인 제어알고리즘이 갖는 주행오차저감방법에 관해 연구하였다. 청소로봇의 양 바퀴의 속도에 따라 그려지는 이상적인 회전반경과 실제 실험을 통해 그려지는 회전반경은 다르다. 이는 청소로봇이 주행 시 나타나는 오차가 원인이다. 많은 이론적인 제어알고리즘이 청소로봇의 주행에 잘 적용되기 위해 주행 시 나타나는 오차를 수정하거나 보상해야 한다. 본 연구에서는 이상적인 회전반경과 실험을 통해 얻은 회전반경의 비교를 통해 오차와 회전반경을 구하고 이를 주행에 적용하고자 한다.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2008년도 제38차 하계학술발표논문집 16권1호
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• pp.205-209
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• 2008

본 논문은 입력되는 영상에서 특정 객체를 찾기 위하여 특징 검출 및 매칭 결과를 분석하여 기술한다. 영상의 특징을 추출하는 방법 중 코너를 특징으로 하는 방법인 해리스 코너 검출(Harris corner detection)을 이용하여 코너를 추출하였으며, 추출한 특징을 이용하여 다양한 크기의 템플릿을 만들어 입력된 영상과 상관계수를 구해 최대값을 가지는 위치를 찾아 입력된 영상과 객체를 매칭 시킨 결과를 분석하였다. 본 논문의 연구 결과들은 객체의 탐지 등과 같은 영상 분석 기반 기술에 활용될 수 있으리라 기대된다.

• 제어로봇시스템학회논문지
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• 제11권5호
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• pp.463-470
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• 2005

This paper describes a method aimed at improving dead-reckoning accuracy with gyroscopes in mobile robots. The method is a precision calibration procedure for gyroscopes, which effectively reduces the ill effects of nonlinearity of the scale-factor and temperature dependency. This paper also describes the methods of gyro data collection fur all ambient temperature$(-40^{\circ}C{\~}+80^{\circ}C)$ using cubic spline interpolation and defining the error function. The sensor used was a vibrating gyroscope called the EWTS82NA21, which is low lost and commonly used in car navigation system, made by Panasonic. This angular rate sensor utilizes Coriolis force generated by a vibrating tuning fork. The paper also provides experimental results to check the performance and the effectiveness of the proposed method.

• 제어로봇시스템학회논문지
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• 제17권4호
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• pp.375-381
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• 2011

This paper deals with the improvement of visual path following through velocity variation according to the coordinate of feature points. Visual path follow first teaches driving path by selecting milestone images then follows the route by comparing the milestone image and current image. We follow the visual path following algorithm of Chen and Birchfield [8]. In [8], they use fixed translational and rotational velocity. We propose an algorithm that uses different translational velocity according to the driving condition. Translational velocity is adjusted according to the variation of the coordinate of feature points on image. Experimental results including diverse indoor cases show the feasibility of the proposed algorithm.

• 대한임베디드공학회논문지
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• 제9권3호
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• pp.165-171
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• 2014

In this paper, we propose the hardware and software of a test-bed of a hovering AUV (autonomous underwater vehicle). Test-bed to develop as the underwater robot for the hovering -type is planning to apply for marine resource development and exploration for deep sea. The RTU that controls a azimuth thruster and a vertical thruster of test-bed is a intergrated-type thruster. The main control unit that collects sensor's data and performs high-speed processing and controls a movement of test-bed is a underwater hybrid navigation system. Also it transfers position, posture, state information of test-bed to the host PC of user using a wireless communication. The host PC checks a test-bed in real time by using a realtime monitoring system that is implemented by LabVIEW.

• 한국정보처리학회논문지
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• 제2권3호
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• pp.343-353
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• 1995

자율 운송 장치나 이동 로보트에 대한 경로 이동 문제는 이동하고자 하는 환경을 완전히 알고 있거나, 장애물이 고정된것으로 가정해 왔다. 따라서, 임의의 환경에 대해 부분적으로 알고 있거나 미지의 환경에서의 자율 운송 장치의 운항을 위해서는 이들 경로 기법은 직접적인 적용이 불가능하고, 확장이 어렵다. 본 논문에서는 이들 문제점을 개선하기 위해서 쿼드트리 기법을 도입하였으며, 임의의 환경에서 자율적으 로 경로 계획을 할 수 있는 알고리즘을 제안하였고, 알고리즘의 타당성을 시뮬레이션 을 통해 증명하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2183-2185
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• 1998

In this paper, we propose a method of designing neural networks using biological inspired developmental and evolutionary concept. The living things are best information processing system in themselves. One individual is developed from a generative cell. And a species of this individual have adapted itself to the environment by evolution. Ontogeny of organism is embodied in cellular automata and phylogeny of species is realized by evolutionary algorithms. The connection among cells is determined by a rule of cellular automata. In order to obtain the best neural networks in the environment, we evolve the arrangement of initial cells. The cell, that is neuron of neural networks, is modeled on chaotic neuron with firing or rest state like biological neuron. A final output of network is measured by frequency of firing state. The effectiveness of the proposed scheme is verified by applying it to navigation problem of robot.

• 제어로봇시스템학회논문지
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• 제8권11호
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• pp.935-940
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• 2002

For robot navigation and visual reconstruction, structure from motion (SFM) is an active issue in computer vision community and its properties arc also becoming well understood. In this paper, when using stereo image sequence and direct method as a tool for SFM, we present a new method for overcoming bas-relief ambiguity. We first show that the direct methods, based on optical flow constraint equation, are also intrinsically exposed to such ambiguity although they introduce robust methods. Therefore, regarding the motion and depth estimation by the robust and direct method as approximated ones. we suggest a method that refines both stereo displacement and motion displacement with sub-pixel accuracy, which is the central process f3r improving its ambiguity. Experiments with real image sequences have been executed and we show that the proposed algorithm has improved the estimation accuracy.