• International Journal of Control, Automation, and Systems
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• 제1권2호
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• pp.229-235
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• 2003

We designed a family of completely autonomous mobile robots with local intelligence. Each robot has a number of on-board sensors, including vision, and does not rely on global positioning systems The on-board embedded controller is sufficient to analyze several low-resolution color images per second. This enables our robots to perform several complex tasks such as navigation, map generation, or providing intelligent group behavior. Not being limited to playing the game of soccer and being completely autonomous, we are also looking at a number of other interesting scenarios. The robots can communicate with each other, e.g. for exchanging positions, information about objects or just the local states they are currently in (e.g. sharing their current objectives with other robots in the group). We are particularly interested in the differences between a behavior-based approach versus a traditional control algorithm at this still very low level of action.

• Journal of Positioning, Navigation, and Timing
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• 제1권1호
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• pp.35-43
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• 2012

The UGV is one of the special field robot developed for mine detection, surveillance and transportation. To achieve successfully the missions of the UGV, the accurate and reliable navigation data should be provided. This paper presents design and implementation of multi-sensor-based open architecture integrated navigation for localization of UGV. The presented architecture hierarchically classifies the integrated system into four layers and data communications between layers are based on the distributed object oriented middleware. The navigation manager determines the navigation mode with the QoS information of each navigation sensor and the integrated filter performs the navigation mode-based data fusion in the filtering process. Also, all navigation variables including the filter parameters and QoS of navigation data can be modified in GUI and consequently, the user can operate the integrated navigation system more usefully. The conventional GPS/INS integrated system does not guarantee the long-term reliability of localization when GPS solution is not available by signal blockage and intentional jamming in outdoor environment. The presented integration algorithm, however, based on the adaptive federated filter structure with FDI algorithm can integrate effectively the output of multi-sensor such as 3D LADAR, vision, odometer, magnetic compass and zero velocity to enhance the accuracy of localization result in the case that GPS is unavailable. The field test was carried out with the UGV and the test results show that the presented integrated navigation system can provide more robust and accurate localization performance than the conventional GPS/INS integrated system in outdoor environments.

• 한국통신학회논문지
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• 제40권8호
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• pp.1655-1666
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• 2015

본 논문에서는 Fingerprint 기법의 Resource로 신호의 세기가 아닌 이미지를 이용해 좌표정보를 포함하는 이미지 기반의 데이터베이스를 구축하고, 사용자로부터 입력되는 이미지와 유사도 비교를 통해 사용자의 위치추정 기법에 대해 제안한다. Fingerprint 기법은 신호 세기뿐만 아니라 환경에 대한 지역적 잡음 정보들까지 모두 추정에 반영하므로 높은 위치 추정 정확도를 제공한다. 이미지의 유사도는 SURF 알고리즘을 통해 데이터베이스와 사용자 입력 이미지의 특징점을 검출하고, 동일한 특징점 간의 매칭을 통해 비교된다. 여기에서 우리는 RANSAC 알고리즘을 함께 사용하여 검출된 특징점의 노이즈 제거를 통해 이미지 유사도 비교의 정확도를 높였다. 제안하는 기법의 검증을 위해 두 건물의 실내와 주변 실외 환경에서 이미지를 획득하여 데이터베이스를 구축하고, 임의의 위치에서 사용자의 위치를 추정하였다. 추정 된 최종 위치는 데이터베이스에 저장 된 이미지가 가지는 좌표가 사용자의 위치와 가장 근접한 좌표로 검출되는지 확인하였으며 RANSAC을 통해 특징점의 노이즈 제거 전과 제거 후에 대한 이미지 유사도 비교의 성능을 분석하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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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.

• 제어로봇시스템학회논문지
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• 제15권5호
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• pp.548-554
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• 2009

We propose an automatic inspection system for hologram with multiple patterns. The system hardware consists of illuminations, camera, and vision processor. Multiple illuminations using LEDs are arranged in different directions to acquire each image of patterns. The system software consists of pre-processing, pattern generation, and pattern matching. The acquired images of input hologram are compared with their reference patterns by developed matching algorithm. To compensate for the positioning error of input hologram, reference patterns of hologram for different position should be generated in on-line. We apply a frequency transformation based CGH(computer-generated hologram) method to generate reference images. For the fast pattern matching, we also apply the matching method in the frequency domain. Experimental results for hologram of Korean currency are then presented to verify the usefulness of proposed system.

• 한국정밀공학회지
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• 제27권1호
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• pp.125-133
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• 2010

A versatile micro-robotic platform for micro/nano scale assembly has been demanded in a variety of application areas such as micro-biology and nanotechnology. In the near future, a flexible and compact platform could be effectively used in a scanning electron microscope chamber. We are developing a platform that consists of miniature mobile robots and a compact positioning stage with multi degree-of-freedom. This paper presents the design and the implementation of a low-cost and compact multi degree of freedom position sensor that is capable of measuring absolute translational and rotational displacement. The proposed sensor is implemented by using a CMOS type image sensor and a target with specific hole patterns. Experimental design based on statistics was applied to finding optimal design of the target. Efficient algorithms for image processing and absolute position decoding are discussed. Simple calibration to eliminate the influence of inaccuracy of the fabricated target on the measuring performance also presented. The developed sensor was characterized by using a laser interferometer. It can be concluded that the sensor system has submicron resolution and accuracy of ${\pm}4{\mu}m$ over full travel range. The proposed vision-based sensor is cost-effective and used as a compact feedback device for implementation of a micro robotic platform.

• 한국지능시스템학회논문지
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• 제11권7호
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• pp.603-610
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• 2001

Industrial processes are normally operated by skilled humans who have the cumulative and logical information about the system. Fuzzy control has been investigated for many application. Intelligent control approaches based on fuzzy logic have a chance to include human thinking. This paper represents modeling approach based upon operators knowledge without mathematical model of the system and optimize the controller. The experimented system is constructed for sending a ball to the goal position using wind of two DC motors in the predefined path. A vision camera to mimic human eyes detects the ball position. The system used in this experiment could be hardly modeled by mathematical methods and ould not be easily controlled by conventional manners. The controller is designed based on the input-output data and experimental knowledge obtained by trials, and optimized under the predefined performance criterion. And this paper shows the data adaptation for changeable operating condition. When the system is driven in the abnormal condition with unconsidered noise, the new optimal operating parameters could be defined by adjusting membership functions. Thus, this technique could be applied in industrial fields.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권8호
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• pp.3889-3903
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• 2017

Fast and accurate localization of randomly deployed nodes is required by many applications in wireless sensor networks (WSNs). However, mobile nodes localization in WSNs is more difficult than static nodes localization since the nodes mobility brings more data. In this paper, we propose a Range-based Monte Carlo Box (RMCB) algorithm, which builds upon the Monte Carlo Localization Boxed (MCB) algorithm to improve the localization accuracy. This algorithm utilizes Received Signal Strength Indication (RSSI) ranging technique to build a sample box and adds a preset error coefficient in sampling and filtering phase to increase the success rate of sampling and accuracy of valid samples. Moreover, simplified Particle Swarm Optimization (sPSO) algorithm is introduced to generate new samples and avoid constantly repeated sampling and filtering process. Simulation results denote that our proposed RMCB algorithm can reduce the location error by 24%, 14% and 14% on average compared to MCB, Range-based Monte Carlo Localization (RMCL) and RSSI Motion Prediction MCB (RMMCB) algorithm respectively and are suitable for high precision required positioning scenes.

• 융합신호처리학회논문지
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• 제5권4호
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• pp.256-262
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• 2004

로봇이 자율주행을 하는데 있어 중요한 요소는 로봇 스스로 위치를 추정하고 동시에 주위 환경에 대한 지도를 작성하는 것이다. 본 논문에서는 어안렌즈를 이용한 비전 기반 위치 추정 및 매핑 알고리즘을 제안한다. 로봇에 어안렌즈가 부착된 카메라를 천정을 바라볼 수 있도록 부착하여 스케일 불변 특징을 갖는 고급의 영상 특징을 구하고, 이 특징들을 맵 빌딩과 위치 추정에 이용하였다. 전처리 과정으로 어안렌즈를 통해 입력된 영상을 카메라 보정을 행하여 축방향 왜곡을 제거하고 레이블링과 컨벡스헐을 이용하여 보정된 영상에서 천정영역과 벽영역으로 분할한다. 최초 맵 빌딩시에는 분할된 영역에 대해 특징점을 구하고 맵 데이터베이스에 저장한다. 맵 빌딩이 종료될 때까지 연속하여 입력되는 영상에 대해 특징점들을 구하고 맵과 매칭되는 점들을 찾고 매칭되지 않은 점들에 대해서는 기존의 맵에 추가하는 과정을 반복한다. 위치 추정은 맵 빌딩 과정과 맵 상에서 로봇의 위치를 찾는데 이용된다. 로봇의 위치에서 구해진 특징점들은 로봇의 실제 위치를 추정하기 위해 기존의 맵과 매칭을 행하고 동시에 기존의 맵 데이터베이스는 갱신된다. 제안한 방법을 적용하면 50㎡의 영역에 대한 맵 빌딩 소요 시간은 2분 이내, 위치 추정시 위치 정확도는 ±13cm, 로봇의 자세에 대한 각도 오차는 ±3도이다.

• 한국멀티미디어학회논문지
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• 제15권11호
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• pp.1273-1283
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• 2012

본 논문에서는 참외 수확로봇을 위한 비전 기반 참외 위치인지 알고리즘을 제시하였다. 입력된 영상의 RGB값을 HSI값으로 변환 후 Hue 값을 이용하여 이진화를 수행한 후에 참외 영역을 추출하였다. 형태학적 필터링을 이용하여 잡음을 제거한 후에 경계선 검출과 convex hull 기법을 이용하여 최외각 정점을 검출하였다. RANSAC 알고리즘에 의하여 참외에 대한 타원 정합을 수행하고 참외의 중심점, 장축 및 단축의 길이, 회전각도에 대한 정보를 획득하였다. 참외 모델에 대한 다양한 시뮬레이션 실험에 의해 제안한 방법의 유효성을 검증하였고, 실제 참외에 적용시켜 제안한 방법의 타당성을 확인하였다.