• 로봇학회논문지
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• 제1권2호
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• pp.117-124
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• 2006

In this paper, we develope the navigation system for patrol robots in indoor environment. The proposed system consists of PDA map modelling, a localization algorithm based on a global position sensor and an automatic charging station. For the practical use in security system, the PDA is used to build object map on the given indoor map. And the builded map is downloaded to the mobile robot and used in path planning. The global path planning is performed with a localization sensor and the downloaded map. As a main controller, we use PXA270 based hardware platform in which embedded linux 2.6 is developed. Data handling for various sensors and the localization algorithm are performed in the linux platform. Also, we implemented a local path planning algorithm for object avoidance with ultra sonar sensors. Finally, for the automatic charging, we use an infrared ray system and develop a docking algorithm. The navigation system is experimented with the two-wheeled mobile robot using North-Star localization system.

• 한국항행학회논문지
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• 제16권5호
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• pp.839-845
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• 2012

본 논문에서는 임베디드 웹 서버(Embedded Web Server)를 이용하여 원격에서 다양한 입출력 장치들의 상태를 계측하거나 이들을 제어하는 시스템을 설계하고 개발한다. 설계된 원격 제어 및 계측시스템은 Cortex-M3 ARM 마이크로컨트롤러를 사용하여 구현되었으며, 제어 및 계측 시스템 사용자를 위한 사용자 응용 프로그램, 그리고 디지틀 입출력 장치, AD/DAC, LCD 및 온습도 센서 등의 구동장치 프로그램 및 이벤트 처리를 위한 웹서버 프로그램을 구현하였다. 각각의 프로그램은 Eclipse 개발환경을 구축하여 Codesourcery C 언어, Java script, 그리고 HTML 언어를 사용하여 작성되었다. 본 논문에서 구현된 제어 및 계측 시스템의 실험결과는 실제로 실시간 실험을 통해, 설계된 바와 같이 사용자가 원하는 동작을 정확하게 수행하는 것을 확인하였다.

• 대한임베디드공학회논문지
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• 제11권3호
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• pp.193-200
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• 2016

This paper introduces an algorithm to middle-low price drone's autonomous navigation flight system using computer vision and GPS. Existing drone operative system mainly contains using methods such as, by inputting course of the path to the installed software of the particular drone in advance of the flight or following the signal that is transmitted from the controller. However, this paper introduces new algorithm that allows autonomous navigation flight system to locate specific place, specific shape of the place and specific space in an area that the user wishes to discover. Technology developed for military industry purpose was implemented on a lower-quality hobby drones without changing its hardware, and used this paper's algorithm to maximize the performance. Camera mounted on middle-low price drone will process the image which meets user's needs will look through and search for specific area of interest when the user inputs certain image of places it wishes to find. By using this algorithm, middle-low price drone's autonomous navigation flight system expect to be apply to a variety of industries.

• Journal of information and communication convergence engineering
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• 제8권6호
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• pp.709-715
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• 2010

This paper represents a map building and localization system for mobile robot. Map building and navigation is a complex problem because map integrity cannot be sustained by odometry alone due to errors introduced by wheel slippage, distortion and simple linealized odometry equation. For accurate localization, we propose sensor fusion system using encoder sensor and indoor GPS module as relative sensor and absolute sensor, respectively. To build a map, we developed a sensor based navigation algorithm and grid based map building algorithm based on Embedded Linux O.S. A wall following decision engine like an expert system was proposed for map building navigation. We proved this system's validity through field test.

• 한국자동차공학회논문집
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• 제19권4호
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• pp.1-7
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• 2011

Various convenient systems which are telecommunication and navigation system and safety system which include Antilock Braking System, Electronic Stability Control, Adaptive Cruise Control have been developed and applied to meet customer needs and each standards since vehicles are used. The complexity of new electronics become significant reason of breakdown especially embedded software failures. Hardware reliability is almost stabilized with long history but software reliability needs more improvements through reliability researches. This new challenge will improve software reliability to clear its overall failures in vehicles. This paper introduces some software reliability models and evaluates embedded software reliability using failure data which occurred during operating.

• 대한임베디드공학회논문지
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• 제19권3호
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• pp.131-139
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• 2024

Crew Transfer Vessels (CTVs) are primarily used for the maintenance of offshore wind farms. Despite being manually operated by professional captains and crew, collisions with other ships and marine structures still occur. To prevent this, the introduction of autonomous navigation systems to CTVs is necessary. In this study, research on the obstacle avoidance system of the autonomous navigation system for CTVs was conducted. In particular, research on obstacle avoidance simulation for CTVs using deep reinforcement learning was carried out, taking into account the currents and wind loads in offshore wind farms. For this purpose, 3 degrees of freedom ship maneuvering modeling for CTVs considering the currents and wind loads in offshore wind farms was performed, and a simulation environment for offshore wind farms was implemented to train and test the deep reinforcement learning agent. Specifically, this study conducted research on obstacle avoidance maneuvers using MATD3 within deep reinforcement learning, and as a result, it was confirmed that the model, which underwent training over 10,000 episodes, could successfully avoid both static and moving obstacles. This confirms the conclusion that the application of the methods proposed in this study can successfully facilitate obstacle avoidance for autonomous navigation CTVs within offshore wind farms.

• Journal of Positioning, Navigation, and Timing
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• 제11권4호
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• pp.279-286
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• 2022

In this paper, we designed a software library that produces integrated Global Navigation Satellite System (GNSS) / Inertial Navigation System (INS) navigation information using the raw measurements provided by the GNSS chipset, gyroscope, accelerometer and magnetometer embedded in android smartphone. Loosely coupled integration method was used to derive information of GNSS /INS integrated navigation. An application built in the designed library was developed and installed on the android smartphone. And we conducted field experiments. GNSS navigation messages were collected in the Radio Technical Commission for Maritime Service (RTCM 3.0) format by the Network Transport of RTCM via Internet Protocol (NTRIP). As a result of experiments, it was confirmed that design requirements were satisfied by deriving navigation such as three-dimensional position and speed, course over ground (COG), speed over ground (SOG), heading and protection level (PL) using the designed library. In addition, the results of this experiment are expected to be applicable to maritime navigation applications using smart device.

• 제어로봇시스템학회논문지
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• 제13권1호
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• pp.72-78
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• 2007

Determination of the local vertical is not trivial for a moving vehicle and in general will require corrections for the Earth geophysical deflection. The vehicle's local vertical can be estimated by INS integration with initial alignment in SDINS(Strap Down INS) system. In general, the INS has drift error and it cause the performance degradation. In order to compensate the drift error, GPS/INS augmented system is widely used. And in the event that GPS is denied or unavailable, celestial navigation using star tracker can be a backup navigation system especially for the military purpose. In this celestial navigation system, the vehicle's position determination can be achieved using more than two star trackers, and the accuracy of position highly depends on accuracy of local vertical direction. Modern tilt sensors or accelerometers are sensitive to the direction of gravity to arc second(or better) precision. The local gravity provides the direction orthogonal to the geoid and, appropriately corrected, toward the center of the Earth. In this paper the relationship between direction of center of the Earth and actual gravity direction caused by geophysical deflection was analyzed by using precision orbit simulation program embedded the JGM-3 geoid model. And the result was verified and evaluated with mathematical gravity vector model derived from gravitational potential of the Earth. And also for application purpose, the performance variation of pure INS navigation system was analyzed by applying precise gravity model.

• 전기학회논문지
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• 제59권3호
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• pp.645-650
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• 2010

In this paper we present the Bimodal-tram simulator using the PXI embedded real-time controllers. The Bimodal-tram is developed in KRRI (Korea Railroad Research Institute). The vehicle can be automatically operated by navigation control system (NCS). For the automatic driving, the vehicle lanes will be marked with permanent magnets that are placed in the ground. The vehicle is controlled by NCS. NCS governs the manual mode and automatic mode driving. The simulator is designed by an identical conception with the real control condition. The dynamic motion of vehicle is simulated by the nonlinear dynamic model. The control computer calculates the control values. The signal interface is linked by CAN communication. The simulation is processed by real-time base. The test driver can see the graphic motion of vehicle and can operate the steering wheel, gas and brake pedal to control direction and velocity of vehicle during the simulation. At present, the simulator is only operated by manual mode. The automatic mode will be linked after the control algorithm is finished. We will use the simulator to develop the control algorithm in the automatic mode. This paper shows the simulator designed for Bimodal-tram using real-time based controller. The results of the test using the simulator are presented and discussed.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2021년도 추계학술대회
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• pp.23-24
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• 2021

기존 항로표지의 고장사례 중 항로표지의 임베디드 컴퓨터인 RTU의 SW 및 운영체제 에러가 약 10%를 차지하고 있다. SW 에러의 원인은 무한한 경우의 수를 가지며 이를 모두 수정하는 것은 불가능하다. 본 논문에서는 최근 관리해야하는 SW 서비스들의 연산량과 복잡도가 높아져가는 스마트 항로표지에 대한 안정적인 운영 기법으로 반가상화 다중 OS 도커 컨테이너 활용 기법을 제안했다. 서비스의 타입과 예상되는 로드, 오류 발생 빈도에 따라 컨테이너를 나누고 서비스를 탑재하는 것을 제안 하였다.