• 로봇학회논문지
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• 제18권3호
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• pp.337-345
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• 2023

In this paper, we propose a 3D LiDAR sensor-based costmap generation and path planning algorithm using it for reliable autonomous flight in complex indoor environments. 3D path planning is essential for reliable operation of UAVs. However, existing grid search-based or random sampling-based path planning algorithms in 3D space require a large amount of computation, and UAVs with weight constraints require reliable path planning results in real time. To solve this problem, we propose a method that divides a 3D space into several 2D spaces and a path planning algorithm that considers the distance to obstacles within each space. Among the paths generated in each space, the final path (Best path) that the UAV will follow is determined through the proposed objective function, and for this purpose, we consider the rotation angle of the 2D space, the path length, and the previous best path information. The proposed methods have been verified through autonomous flight of UAVs in real environments, and shows reliable obstacle avoidance performance in various complex environments.

• 대한조선학회논문집
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• 제60권5호
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• pp.351-357
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• 2023

In this study, we devised methods to enhance the efficiency of rotor sails which have been applied as one of the energy saving devices of ships. The idea of the study originated from the notion that installing protrusions or increasing the surface roughness on the smooth surface of the rotor sail could delay the separation of the incoming wind flow and consequently increase the lift force. Five cylinder models were considered and tested in an open-type wind tunnel at Chungnam National University. A smooth surface cylinder exhibits the highest lift-to-drag ratio at a specific Reynolds number, and as the Reynolds number increases this value decreases sharply. The variation in this typical Magnus force can be significantly improved by altering the surface shape and roughness of the rotor sail. It has been observed that increasing the surface roughness improves the lift characteristics, resulting in increased efficiency. Furthermore, it revealed that the reverse Magnus effect which may occur during actual operation in the low spin ratio region can be significantly enhanced.

• 로봇학회논문지
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• 제19권3호
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• pp.311-317
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• 2024

Large-scale three-wheeled cleaning robots are utilized to clean large spaces such as warehouses and manufacturing plants where significant floor contamination occurs. Although there are autonomous cleaning robots, user-operated cleaning robots are often preferred because they are easy to repair and inexpensive. Therefore, workers have to spend extra time on cleaning, which reduces work efficiency. In this paper, we propose an autonomous driving system designed to automate the operation while maintaining the structure of existing cleaning robots. The contributions of this paper are as follows: 1) Hardware modules that control the driving and steering components. 2) A LiDAR-based autonomous driving system and path point generation system considering the mechanical characteristics of the cleaning robot. 3) The proposed system is implemented on an actual cleaning robot and driving tests are performed. As a result, when path planning is performed to cover the cleaning area, the average RMSE for each straight path is 0.0802 m, which is smaller than the minimum cleaning overlap of 0.3 m that occurs during the straight cleaning of the robot. This shows that the proposed system effectively covers the entire cleaning area.

• 한국주거학회논문집
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• 제25권3호
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• pp.131-143
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• 2014

The purpose of this study is to develop an operation manual of resident-driven community program by evaluating community program operation to realize a sustainable apartment complex and vitalize a community. To achieve this purpose, 8 community experts, who are in charge of 42 complexes of 7 autonomous districts among 25 districts in Seoul were interviewed from September 2013 to December 2013. Main results of the study are as follows. 1) Operational problems and improvements are deduced from evaluating operation process of community programs. It is found that smooth cooperation of main operators including a community vitalization association, a resident representative meeting and a control office is the most important. 2) Operation guideline for representative programs are suggested based on analysis of operational characteristics of 3 types of community programs; communication, recycling and environment management, according to program operation elements; material element, programming element, human element and finance element. 3) An operation manual of resident-oriented community program is presented after considering evaluation of operation processes and analysis of 3 types of operational elements of community programs.

• 전기전자학회논문지
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• 제22권1호
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• pp.223-226
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• 2018

최근 차량 사고로부터 탑승자를 보호하기 위해서 다양한 안전 기술이 집중적으로 개발되고 있다. 본 논문에서는 잠김 방지 브레이크 시스템, 견인력 제어 시스템, 제동력 배분 시스템, 전자 주행 안정 장치, 자동 긴급 브레이크, 에어백, 좌석벨트 프리텐셔너, 능동형 헤드레스트 등 다양한 차량용 탑승자 보호 기술을 살펴보고, 각 기술의 동작원리 및 구현에 대해 설명한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.349-351
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• 2007

A concept of the semi-autonomous tele-weeding-system which performs weeding tasks through co-operation of human and machine intelligence is proposed. The tele-weeding system consists of weeding robot, communication networks and operating server. The images of plants taken by the weeding robot are transferred through the communication networks to the human operator. Positions of the weeds are indicated at the operating host by the operator and transferred back to the weeding robot. Such position informations are converted to the world space and the weeding is done based on the robot intelligence. Feasibility of such concept has been tested through development of a laboratory model of the system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.400-400
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• 2000

This paper purposed that verify the validity of Petri Net method for control progressive increase of system complexity, before extend the realized single robot system to multi-robot system. An autonomous mobile robot(AMR) needs decision making, motion control, path planning, tracking a path, obstacle avoidance, and sensor fusion, to complete its task. An AMR integrates and operates these technics through a consistent command system. An error in a command hierarchy which is like duplication or omission of a control command hierarchy for each module results in serious problems. This paper minimizes the error by modeling each module and whole system using Petri Net graphical representation and applies it to the exploration task of an AMR

• 제어로봇시스템학회논문지
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• 제17권5호
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• pp.444-450
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• 2011

Environmental change, labor shortage, and international trade politics make agricultural automation ever more important. The automation demands the highest technology due to the nature of agriculture. In this paper, autonomous pesticide spray robot system has been developed for rose farming in the glass house. We developed drive platform, navigation/localization system, atomization spray system, autonomous, remote, and manual operation system, and monitoring system. The robot will be a great contribution to automation of hazardous labor-demanding chore of pesticide control in glass houses.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제2권5호
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• pp.353-358
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• 2013

본 논문에서는 실내 환경에서 컴퓨터비전, 스마트폰과 헬륨을 사용하여 특정한 장소를 찾아갈 수 있는 자동비행체 구현 방법을 제안한다. 먼저, 마커를 이용하여 빌딩 내 각 정점을 표시하고, 다익스트라 알고리즘을 활용하여 자동으로 최단의 경로를 찾는다. 제안된 방법을 이용하여 그 경로를 따라 비행하기 위한 최적의 비행체 구조를 설계한다. 실험 결과 다양한 방면으로 적용 가능한 유의미한 결과를 얻었다.

• Journal of Positioning, Navigation, and Timing
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• 제10권2호
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• pp.91-102
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• 2021

In this paper, a fully reconfigurable Software Defined Radio (SDR) for multi-constellation and multi-frequency Global Navigation Satellite System (GNSS) receivers is presented. The reconfigurability with respect to the data structure, variability of signal and receiver parameters, and receiver's internal functionality is presented. The configuration file, that is modified to lead to an entirely different operation of the SDR in response to specific target signal scenarios, directly determines the operating characteristics of the SDR. In this manner, receiver designers can effectively reduce the effort to develop many different combinations of multi-constellation and/or multi-frequency GNSS receivers. Finally, the implementation of the presented fully reconfigurable SDR is included with the experimental processing results such as acquisition, tracking, navigation for the received signals in the realistic fields.