• 한국통신학회논문지
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• 제38C권5호
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• pp.471-478
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• 2013

본 논문은 국내 철도 건널목의 현황 조사와 현재 운영되고 있는 안전설비의 문제점 분석을 통해 이를 해결할 수 있는 대안으로 레이저레이더기반의 지장물 검지장치를 설계 및 구현하였다. 철도 안전사고의 큰 비중을 차지하는 철도 건널목에서의 효과적인 지장물 검지를 통해 철도교통의 안전성 및 신뢰성 향상을 목표로 하며, 기존 안전 설비의 한계와 노후화로 인한 문제점을 극복하는 시스템을 제안한다. 레이저레이더 스캐너를 활용한 철도 건널목 지장물 검지장치를 설계하였고 시제품 시험 및 성능평가를 통해 이를 입증하였다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제3권2호
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• pp.244-250
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• 2003

In this paper, the relationship between a slave robot and the uncertain remote environment is modeled as the impedance to generate the virtual force to feed back to the operator. For the control of a tele-operated mobile robot equipped with camera, the tele-operated mobile robot take pictures of remote environment and sends the visual information back to the operator over the Internet. Because of the limitation of communication bandwidth and narrow view-angles of camera, it is not possible to watch the environment clearly, especially shadow and curved areas. To overcome this problem, the virtual force is generated according to both the distance between the obstacle and robot and the approaching velocity of the obstacle. This virtual force is transferred back to the master over the Internet and the master(two degrees of freedom joystick), which can generate force, enables a human operator to estimate the position of obstacle in the remote environment. By holding this master, in spite of limited visual information, the operator can feel the spatial sense against the remote environment. This force reflection improves the performance of a tele-operated mobile robot significantly.

• 한국컴퓨터정보학회논문지
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• 제12권5호
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• pp.155-162
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• 2007

스마트한 홈서비스를 제공하기 위해서는 가전기기를 제어하기위한 미들웨어 기술과 사용자의 위치를 기반 서비스를 위한 사용자의 위치 정보가 중요하다. 기존에 연구되는 초음파 및 전파를 사용한 기술은 장애물 및 주변 환경의 영향을 많이 받는다. 따라서 본 논문에서는 사용자의 위치 추정에 장애물 등의 영향을 받지 않는 관성센서를 사용하고, RFID를 사용하여 초기 위치를 설정하는 기법을 제안한다. 이 기법을 사용하여 초기 위치를 상대 좌표가 아닌 실제 좌표로 바로 할당할 수 있게 하여 이를 통해 관성센서의 단점인 오차누적 문제를 해결한다. 본 논문에서 제안하는 시스템은 서비스제공 및 확장성을 위한 미들웨어와 미들웨어 상위계층에서 동작하는 사용자 위치 추정시스템, 그리고 사용자의 위치계산을 위한 데이터를 수집하는 관성센서 및 RFID Reader로 구성한다. 또한 스마트 홈 환경에서 본 논문에서 제안한 시스템이 장애물의 영향을 받지 않고 동작하는 것을 확인한다.

• 제어로봇시스템학회논문지
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• 제9권8호
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• pp.585-591
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• 2003

A virtual force is generated and fed back to the operator to make the teleoperation more reliable, which reflects the relationship between a slave robot and an uncertain remote environment as a form of an impedance. In general, for the teleoperation, the teleoperated mobile robot takes pictures of the remote environment and sends the visual information back to the operator over the Internet. Because of the limitations of communication bandwidth and narrow view-angles of camera, it is not possible to watch certain regions, for examples, the shadow and curved areas. To overcome this problem, a virtual force is generated according to both the distance between the obstacle and the robot and the approaching velocity of the obstacle w.r.t the collision vector based on the ultrasonic sensor data. This virtual force is transferred back to the master (two degrees of freedom joystick) over the Internet to enable a human operator to estimate the position of obstacle at the remote site. By holding this master, in spite of limited visual information, the operator can feel the spatial sense against the remote environment. It is demonstrated by experiments that this collision vector based haptic reflection improves the performance of teleoperated mobile robot significantly.

• 로봇학회논문지
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• 제17권4호
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• pp.500-507
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• 2022

In this study, a motion planning method based on the integer representation of contact status between wheels and the ground is proposed for planning swing motion of a 6×6 wheel-legged robot to cross large obstacles and gaps. Wheel-legged robots can drive on a flat road by wheels and overcome large obstacles by legs. Autonomously crossing large obstacles requires the robot to perform complex motion planning of multi-contacts and wheel-rolling at the same time. The lift-off and touch-down status of wheels and the trajectories of legs should be carefully planned to avoid collision between the robot body and the obstacle. To address this issue, we propose a planning method for swing motion of robot legs. It combines an integer representation of discrete contact status and a trajectory optimization based on the direct collocation method, which results in a mixed-integer nonlinear programming (MINLP) problem. The planned motion is used to control the joint angles of the articulated legs. The proposed method is verified by the MuJoCo simulation and shows that over 95% and 83% success rate when the height of vertical obstacles and the length of gaps are equal to or less than 1.68 times of the wheel radius and 1.44 times of the wheel diameter, respectively.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1167-1172
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• 2007

Generally inpipe robot needs force above standing for contacting robot to pipe. If the environment of the pipe-inside does not change, there is not a problem. But if the pipe radius change, or occur the obstacle which it does not intend, problem gets. So it uses a different system and must know an environment change, and changing the shape or a form of the robot. The research uses the flexible leg and is the robot which is adapted to the environment change of the pipe. The advantage of this robot is possible to move when it does not need to recognize a change of environment of pipe. Leg is bend with one direction. When it moves part that there are legs effect of leg direction the robot is moved with only one direction. If friction between legs and pipe is sufficient, not only verticality pipe moving, but also curved pipe moving. Also the obstacle of the pipe inside occurs and the diameter of the pipe inside changes, this robot can move if it does not use another system or device.

• 제어로봇시스템학회논문지
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• 제19권7호
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• pp.614-619
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• 2013

In multi-robot systems, ultrasonic sensors are widely used for localization and/or obstacle detection. However, conventional ultrasonic sensors have a drawback, that is, the interference problem among ultrasonic transmitters. There are some previous studies to avoid interferences, such as TDMA (Time Division Multiple Access) and CDMA (Code Division Multiple Access). In multiple autonomous mobile robots systems, the Doppler-effect has to be considered because ultrasonic transceivers are attached to the moving robots. To overcome this problem, we find out the ASK (Amplitude Shift Keying)-CDMA technique is more robust to the Doppler-effect than the BPSK (Binary Phase Shift Keying)-CDMA technique. In this paper, we propose a new code-expression method and a Monte-Carlo based algorithm that optimizes the ultrasonic code combination in the ASK-CDMA ultrasonic system. The experimental results show that the proposed algorithm improves the performance of the ultrasonic multiple accessing capacity in the ASK-CDMA ultrasonic system.

• 제어로봇시스템학회논문지
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• 제17권5호
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• pp.405-411
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• 2011

This paper presents a hierarchical trajectory planning method which can handle a collision-free of the planned path in complex and dynamic environments. A PV (Path & Velocity profile) planning method minimizes a sharp change of orientation and waiting time to avoid a collision with moving obstacle through detour path. The path generation problem is solved by three steps. In the first step, a smooth global path is generated using $A^*$ algorithm. The second step sets up the velocity profile for the optimization problem considering the maximum velocity and acceleration. In the third step, the velocity profile for obtaining the shortest path is optimized using the fuzzy and genetic algorithm. To show the validity and effectiveness of the proposed method, realistic simulations are performed.

• 한국해양공학회지
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• 제26권4호
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• pp.1-7
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• 2012

This paper deals with the global path planning problem for AUVs (autonomous underwater vehicles) in a tidal current field. The previous researches in the field were unsuccessful at simultaneously addressing the two issues of obstacle avoidance and tidal current-based optimization. The use of a genetic algorithm is proposed in this paper to move past this limitation and solve both issues at once. Simulation results showed that the genetic algorithm could be applied to generate an optimal path in the field of a tidal current with multiple obstacles.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.319-322
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• 1995

This paper addresses that through the use of Fuzzy Logic Control, a reactiv behavior (e.g. avoiding obstacles on the way) are smoothly blended into one sequence of control action. In this classical problem, the aim is to guide a mobile robot along its path to avoid any static obstacles in front of it. This controller presented here uses three sub-controllers. This fuzzy controller was apply to a miniature mobile robot. This robot follows a left wall, maintining a minimum distance.