• ETRI Journal
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• 제40권4호
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• pp.446-457
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• 2018

Robot navigation allows robot mobility. Therefore, mobility is an area of robotics that has been actively investigated since robots were first developed. In recent years, interest in personal service robots for homes and public facilities has increased. As a result, robot navigation within the home environment, which is an indoor environment, is being actively investigated. However, the problem with conventional navigation algorithms is that they require a large computation time for their building mapping and path planning processes. This problem makes it difficult to cope with an environment that changes in real-time. Therefore, we propose a humanoid robot navigation algorithm consisting of an image processing and optimization algorithm. This algorithm realizes navigation with less computation time than conventional navigation algorithms using map building and path planning processes, and can cope with an environment that changes in real-time.

• 대한임베디드공학회논문지
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• 제7권1호
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• pp.25-31
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• 2012

We propose a method for an indoor mobile robot to track user with infrared transmitter. Several infrared receivers attached around by the mobile robot enable the robot to determine the moving direction by comparing the received signal patterns. The cost of the proposed system is not only cheaper than ultrasonic system, image signal processing, RFID, and RSSI method, but also robust against environment change because any complex algorithm is not necessary. In the mobile robot, ultrasonic sensors are equipped to avoid obstacles located in the moving direction, and a simple algorithm is embedded to avoid the case of poor signal reception.

• 제어로봇시스템학회논문지
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• 제22권11호
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• pp.952-959
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• 2016

This paper proposes a novel indoor positioning system (IPS) that uses a calibrated camera sensor network and dense 3D map information. The proposed IPS information is obtained by generating a bird's-eye image from multiple camera images; thus, our proposed IPS can provide accurate position information when objects (e.g., the mobile robot or pedestrians) are detected from multiple camera views. We evaluate the proposed IPS in a real environment with moving objects in a wireless camera sensor network. The results demonstrate that the proposed IPS can provide accurate position information for moving objects. This can improve the localization performance for mobile robot operation.

• 제어로봇시스템학회논문지
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• 제13권8호
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• pp.804-809
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• 2007

Initialization problem is defined for indoor mobile robot as a whole process from arrival to normal operation in a new environment. The unstructured environment make the process much more difficult compared to industrial robot in structured environments. We propose a simple and efficient initialization process based on artificial stars on ceiling. Important task points and paths connecting task points are defined based on the corresponding artificial stars. This approach can be used for all kinds of indoor mobile robots with landmarks used for indoor localization.

• 로봇학회논문지
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• 제4권4호
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• pp.312-319
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• 2009

This paper proposes a low-complexity indoor localization method of mobile robot under the dynamic environment by fusing the landmark image information from an ordinary camera and the distance information from sensor nodes in an indoor environment, which is based on sensor network. Basically, the sensor network provides an effective method for the mobile robot to adapt to environmental changes and guides it across a geographical network area. To enhance the performance of localization, we used an ordinary CCD camera and the artificial landmarks, which are devised for self-localization. Experimental results show that the real-time localization of mobile robot can be achieved with robustness and accurateness using the proposed localization method.

• 제어로봇시스템학회논문지
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• 제15권4호
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• pp.445-450
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• 2009

This paper presents a new mobile robot localization method for indoor robot navigation. The method uses hexagon distributed color-coded patches on the ceiling and a camera is installed on the robot facing the ceiling to recognize these patches. The proposed "cell-coded map", with the use of only seven different kinds of color-coded landmarks distributed in hexagonal way, helps reduce the complexity of the landmark structure and the error of landmark recognition. This technique is applicable for navigation in an unlimited size of indoor space. The structure of the landmarks and the recognition method are introduced. And 2 rigid rules are also used to ensure the correctness of the recognition. Experimental results prove that the method is useful.

• 제어로봇시스템학회논문지
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• 제22권2호
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• pp.75-82
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• 2016

Visible light communication (VLC) using LED lamps is suitable for implementing an indoor positioning system in an indoor environment where the global positioning system (GPS) signal does not reach. In this paper, we present an indoor positioning system for mobile robots using a VLC beacon and fuzzy rules. This system consists of an autonomous mobile robot, VLC modules, and device application software. Fuzzy rules are applied to plan the global and local paths along which the mobile robot navigates indoors. The VLC transmitter modules are attached to the wall or the ceiling as beacons to transmit their own location information. The variable pulse position modulation (VPPM) algorithm is used to transmit data, which is a new modulation scheme for VLC providing a dimming control mechanism for flicker-free optical communication. The mobile robot has a receiver module to receive the location information while performing its mission in the environment where VLC transmitters are deployed.

• 제어로봇시스템학회논문지
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• 제14권11호
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• pp.1139-1145
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• 2008

A robust position sensing system is proposed in this paper for a ubiquitous mobile robot which moves indoors as well as outdoors. The Differential GPS (DGPS) which has a position estimation error of less than 5 m is a general solution when the mobile robot is moving outdoor, while an active beacon system (ABS) with embedded ultrasonic sensors is reliable as an indoor positioning system. The switching from the outdoor to indoor or vice versa causes unstable measurements on account of the reference coordinates and algorithm changes. To minimize the switching time in the position estimation and to stabilize the measurement, a robust position sensing system is proposed. In the system, to minimize the switching delay, the door positions are stored and updated in a database. Using the database, the approaching status of the mobile robot from indoor to outdoor or vice versa has been checked and the switching conditions are prepared before the mobile robot actually moves out or moves into the door. The reliability and accuracy of the robust positioning system based on DGPS and ABS are verified and demonstrated through the real experiments using a mobile robot prepared for this research.

• 로봇학회논문지
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• 제7권1호
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• pp.45-56
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• 2012

This paper proposes how to improve the performance of CSS-based indoor localization system. CSS based localization utilizes signal flight time between anchors and tag to estimate distance. From the distances, the 3-dimensional position is calculated through trilateration. However the error in distance caused from multi-path effect transfers to the position error especially in indoor environment. This paper handles a problem of reducing error in raw distance information. And, we propose the new localization method by pattern matching instead of the conventional localization method based on trilateration that is affected heavily on multi-path error. The pattern matching method estimates the position by using the fact that the measured data of near positions possesses a high similarity. In order to gain better performance of localization, we use EKF(Extended Kalman Filter) to fuse the result of CSS based localization and robot model.

• 정보과학회 논문지
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• 제45권3호
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• pp.211-223
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• 2018

본 논문에서는 실내 서비스 로봇들을 위한 로봇 중심의 방향 관계 표현과 추론 방법을 제안한다. 정성적 공간 관계 추론에 관한 많은 기존 연구들에서는 기준 물체를 중심으로 대상 물체의 상대적 방향 관계를 판별할 때, 두 물체의 위치 정보만을 이용해왔다. 이러한 방향 관계 추론 방법들은 로봇 스스로가 기준 물체가 되어 다른 대상 물체들과의 방향 관계를 판별할 때, 로봇이 바라보고 있는 방향을 제대로 고려하지 않음으로써, 대상 물체의 방향 관계를 잘못 판별하는 사례들이 발생할 수 있다. 본 논문에서는 실내 환경에서 로봇을 중심으로 물체들의 상대적인 방향 관계를 판별할 때, 로봇의 위치 정보뿐만 아니라 로봇이 향하고 있는 방향 정보도 이용하는 로봇 중심의 방향 관계 표현과 방향 관계 추론 방법들을 제시한다. 로봇 중심의 방향 관계 추론 방법들은 두 물체의 위치 정보만을 이용해왔던 기존의 콘 기반 추론, 행렬 기반 추론, 그리고 혼합 추론 방법을 확장하여 구현하였다. 터틀봇과 시뮬레이션 로봇을 이용한 다양한 실험들을 통해, 본 논문에서 제안하는 방향 관계 표현과 추론 방법들의 높은 성능과 적용 가능성을 확인할 수 있었다.