• 로봇학회논문지
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• 제4권3호
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• pp.177-184
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• 2009

This paper presents an active assisted-living system in wireless sensor and actor network (WSAN) in which the mobile robot roles an actor. In order to provide assisted-living service to the elderly people, position recognition of the sensor node attached on the user and localization of the mobile robot should be performed at the same time. For the purpose, we use received signal strength indication (RSSI) to find the position of the person and ubiquitous sensor nodes including ultrasonic sensor which performs both transmission of sensor information and localization like global positioning system. Active services are moving to the elderly people by detecting activity sensor and visual tracking and voice chatting with remote monitoring system.

• 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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• 제12궈1호
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• pp.15-22
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• 2006

This paper presents an efficient localization scheme for an indoor mobile robot using RFID tags on the floor. The mobile robot carries an RFID reader at the bottom, which reads the RFID tags on the floor to localize the mobile robot. Each RFID tar on the floor stores its own absolute position which is used to calculate the position and velocity of the mobile robot. Locating the RFID tags on the floor, which constructs an intelligent sensor space, may require several factors to be considered: economics feasibility and accuracy. In this paper, the optimal allocation scheme of the RFID tags on the floor to satisfy the accuracy constraint has been proposed and verified by the experiments. Based on the RFID reading, the mobile robot navigation has been successfully demonstrated to avoid obstacles and to reach the goal within a pre-specified time.

• 한국BIM학회 논문집
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• 제13권4호
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• pp.64-73
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• 2023

This study introduces a method of estimating the 3D coordinates of structural damage from the detection results of visual inspection provided in 2D image coordinates using sensing data of UAV and 3D shape information of BIM. This estimation process takes place in a virtual space and utilizes the BIM model, so it is possible to immediately identify which member of the structure the estimated location corresponds to. Difference from conventional structural damage localization methods that require 3D scanning or additional sensor attachment, it is a method that can be applied locally and rapidly. Measurement accuracy was calculated through the distance difference between the measured position measured by TLS (Terrestrial Laser Scanner) and the estimated position calculated by the method proposed in this study, which can determine the applicability of this study and the direction of future research.

• Journal of Communications and Networks
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• 제18권5호
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• pp.796-805
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• 2016

In many wireless sensor network (WSN) applications, the information transmitted by an individual entity or node is of limited use without the knowledge of its location. Research in node localization is mostly geared towards multi-hop range-free localization algorithms to achieve accuracy by minimizing localization errors between the node's actual and estimated position. The existing localization algorithms are focused on improving localization accuracy without considering efficiency in terms of energy costs and algorithm convergence time. In this work, we show that our proposed localization scheme, called DV-maxHop, can achieve good accuracy and efficiency. We formulate the multi-objective optimization functions to minimize localization errors as well as the number of transmission during localization phase. We evaluate the performance of our scheme using extensive simulation on several anisotropic and isotropic topologies. Our scheme can achieve dual objective of accuracy and efficiency for various scenarios. Furthermore, the recently proposed algorithms require random uniform distribution of anchors. We also utilized our proposed scheme to compare and study some practical anchor distribution schemes.

• 한국항행학회논문지
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• 제15권1호
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• pp.83-90
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• 2011

위치인식 기술은 사물이나 사람의 위치를 측정하여 서로 정보를 교환하고 환경을 제어하는데 필요한 핵심기술이다. 현재도 위치인식 기술은 다양한 방법들로 연구되고 있으며, 물류, 의학, 로봇 분야 등에 적용될 수 있다. 그러나 위치인식 기술을 적용하려면 많은 비용이 필요하다. 이에 본 논문에서는 적은 비용으로 구현 가능한 Zigbee기반 AoA 위치인식 시스템을 제안한다. 본 시스템은 흔히 이용하는 스텝 모터, 지향성 안테나, Zigbee 모듈을 사용하여 비컨에 지향성 안테나를 회전시켜 RSSI값을 측정하였다. RSSI값이 가장 큰 값을 가질 때 스텝 모터의 회전각을 계산하여 수신기가 위치한 각도를 판단하고 AoA 방식을 적용하여 수신기의 위치를 측정하였다. 수신기의 위치를 옮겨가며 측정한 결과 35~36cm 정도의 오차가 있었다.

• 한국전자통신학회논문지
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• 제6권2호
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• pp.288-295
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• 2011

본 논문에서는 몬테 카를로 방법을 사용한 수중로봇의 위치추정 방법을 제안한다. 수중로봇의 위치추정은 자율 주행을 위한 기본 기능의 하나이다. 제안된 알고리즘에 의하면 추측항법(데드 레크닝 방법)의 약점인 위치 오차 누적 문제를 해결할 수 있다. 제안된 방법은 확률적인 방법으로 로봇 동작의 불확실성과 센서 정보의 불확실성을 처리한다. 특히 칼만 필터 방법과 달리, 로봇의 비선형 운동 특성과 센서의 비가우시안 출력 분포 특성을 모델링할 수 있다. 본 논문에서는 수중로봇 위치 추정에 몬테카를로 위치추정(Monte Carlo Localization : MCL, 이하 MCL로 표기함) 알고리즘을 적용하기 위하여 오일러각을 이용하여 모션모델을 구하였다. 또한 수중로봇에 모션모델과 센서모델을 적용하여 시뮬레이션을 구현하고, 이를 통해 수중로봇에 MCL 알고리즘의 적용 가능성을 보였다.

• 한국정보통신학회논문지
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• 제15권6호
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• pp.1238-1244
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• 2011

본 논문은 레이저 내비게이션의 위치측정을 위한 반사체 매칭방법을 제안하다. 레이저 내비게이션은 벽면에 부착된 반사체의 각도와 거리를 측정하는 장치이고 위치를 측정하기 위해서는 반사체의 매칭 기법이 필요하다. 대표적인 매칭 방법으로는 측정된 반사체의 위치를 이미 알고 있는 반사체의 위치로 평행 이동 한 후, 회전 하면서 매칭하는 방법이었다. 하지만 이 방법은 연산량이 많고 외란에 약하다는 단점이 있다. 이에, 본 논문에서는 연산량을 줄이고 외란에 강인한 반사체 매칭 방법을 제안한다. 제안된 방법은 계측된 반사체들의 위치를 설치된 반사체의 실제 위치로 생성한 후, 계측된 반사체들을 회전하면서 매칭하는 방법이다. 실험은 직접 설계한 AGV를 이용하였으며 조향각과 주행속도를 변화 시키면서 위치측정 정밀도를 비교하였다.

• 제어로봇시스템학회논문지
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• 제14권8호
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• pp.800-808
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• 2008

This paper presents a localization algorithm of the outdoor wheeled mobile robot using the sensor fusion method based on indirect Kalman filter(IKF). The wheeled mobile robot considered with in this paper is approximated to the two wheeled mobile robot. The mobile robot has the IMU and encoder sensor for inertia positioning system and GPS. Because the IMU and encoder sensor have bias errors, divergence of the estimated position from the measured data can occur when the mobile robot moves for a long time. Because of many natural and artificial conditions (i.e. atmosphere or GPS body itself), GPS has the maximum error about $10{\sim}20m$ when the mobile robot moves for a short time. Thus, the fusion algorithm of IMU, encoder sensor and GPS is needed. For the sensor fusion algorithm, we use IKF that estimates the errors of the position of the mobile robot. IKF proposed in this paper can be used other autonomous agents (i.e. UAV, UGV) because IKF in this paper use the position errors of the mobile robot. We can show the stability of the proposed sensor fusion method, using the fact that the covariance of error state of the IKF is bounded. To evaluate the performance of proposed algorithm, simulation and experimental results of IKF for the position(x-axis position, y-axis position, and yaw angle) of the outdoor wheeled mobile robot are presented.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2581-2584
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• 2003

In this paper, we propose a self-localization algorithm using vertical line segments. Indoor environment is consist of horizontal and vertical line features such as doors, furniture, and so on. From the input image, vertical line edges are detected by an edge operator, Then, line segments are obtained by projecting edge image vertically and detecting local maximum from the projected histogram. From the relation of horizontal position of line segments and the location of the robot, nonlinear equations are come out Localization is done by solving the equations by using Newton's method. Experimental results show that the proposed algorithm using one camera is simple and applicable to indoor environment.