• 대한조선학회논문집
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• 제54권2호
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• pp.102-112
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• 2017

Many studies on dynamic positioning control algorithms using fixed feedback gains have been carried out to improve station keeping performance of dynamically positioned vessels. However, the control algorithms have disadvantages in that it can not cope with changes in environmental disturbances and response characteristics of vessels motion in real time. In this paper, the Fuzzy Gain Scheduling - PID(FGS - PID) control algorithm that can tune PID gains in real time was proposed. The FGS - PID controller that consists of fuzzy system and a PID controller uses weighted values of PID gains from fuzzy system and fixed PID gains from Ziegler - Nichols method to tune final PID gains in real time. Firstly, FGS - PID controller, control allocation algorithm, FPSO and environmental disturbances were modeled using Matlab/Simulink to evaluate station keeping performance of the proposed control algorithm. In addition, simulations that keep positions and a heading angle of vessel with wind, wave, current disturbances were carried out. From simulation results, the FGS - PID controller was confirmed to have better performances of keeping positions and a heading angle and consuming power than those of the PID controller. As a consequence, the proposed FGS - PID controller in this paper was validated to have more effectiveness to keep position and heading angle than that of PID controller.

• 한국통신학회논문지
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• 제41권10호
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• pp.1247-1255
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• 2016

소형드론의 상용화를 위해서는 안전성과 자율운행기능의 확보가 필수적이다. 최근 드론제작이 상당히 용이해졌으나, 여전히 안정적인 드론의 제작은 쉽지 않다. 따라서 자체드론제작 필요성은 영상이나 자율이동 등 상위 알고리즘의 연구에 큰 장애요소로 존재한다. 본 연구에서는 상용드론과 Raspberry PI, 및 오픈소스를 활용하여, 쿼드로터 드론의 자율운행기술 개발 중 영상기반 자율운행을 설계해볼 수 있는 지상원격제어시스템(GCS)을 설계하고 구현하였다. 설계한 시스템은 모듈화된 구성으로 통신, UI 및 영상처리 모듈로 구성하였고, 특히 주행선유지 알고리즘을 구현하여 기능 및 성능 실험을 하였다. 설계한 주행선유지 알고리즘은 Hough 변환에 의하여 검출된 차선을 소실점 검출과 자제적인 라인트래킹 알고리즘을 개발하여 사용하여 인식오류를 줄였으며, 주행선과 드론의 진행방향을 계산하고 방향 (전진, 정지, 좌우회전)제어하였다. 구현된 시스템은 현재 100m육상트랙의 직선과 완만한 곡선을 2-3 m/s로 주행할 수 있다.

• 정보처리학회논문지A
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• 제9A권4호
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• pp.413-420
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• 2002

보관 중인 제품의 정확한 위치를 파악하는 것이 창고관리의 필수적인 요소이다. 그러나 제품이 빈번하게 위치를 변경하며 보관되는 경우에는 그 위치 파악이 어렵게 되며 이로 인해 효율적 창고관리가 불가능해진다. 본 논문에서는 임베디드 시스템과 무선 랜을 이용하여, 이러한 이동성이 높은 재고단위(SKU : Stock Keeping Unit)의 창고 내 위치관리에 응용할 수 있는 새로운 시스템을 제안한다. 시스템은 RFID(Radio Frequency IDentification)와 관리 단말기, 모바일 기기인 휴대폰과 PDA 그리고 중앙 관리 시스템으로 구성된다. 시스템의 사례로 이동성이 높은 재고단위의 모델인 대형 중고자동차의 위치관리시스템을 선택하였으며, 시스템이 운용되는 각 부서의 업무를 분석 후 기능별로 구현하였다. 본 연구를 통하여 무선 랜이 접목된 임베디드 시스템이 이동성 높은 재고단위의 입출고 상황과 창고 내에서의 위치를 실시간 적으로 정확하게 파악할 수 있어, 창고의 운영 및 관리를 체계적으로 처리할 수 있음을 보인다.

• 자동차안전학회지
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• 제10권4호
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• pp.33-39
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• 2018

Recently, the automobile industry has developed ADAS (Advanced Driver Assistance System) to prevent traffic accidents and reduce driver's driving burden. Among the ADAS, the LKAS (Lane Keeping Assistance System) is a support system for the convenience and safety of the driver, and the main function is to maintain the driving lane of the vehicle. LKAS is a system that uses radar sensor and camera sensor to collect information about the position of the vehicle in the lane and to support keeping the lane through control if necessary. In many countries, LKAS has already been commercialized and the convenience and safety of drivers have been improved. The international LKAS evaluation test procedure is being developed and discussed by standardization committees such as the ISO (International Organization for Standardization) and the Euro NCAP (New Car Assessment Program). In Korean, the LKAS test method is specified in the KNCAP (Korean New Car Assessment Program), but the evaluation method is not defined. Therefore, the LKAS test procedure that meets international standards and is suitable for domestic road environment is necessary. In this paper, development of LKAS test evaluation scenarios that meets international standards and considering domestic road environment, and the formula that can evaluate the result value after control as the relative distance of lane and the front wheel are suggested. And a comparative analysis was conducted to verify the validity of the suggested scenario and formula. The test evaluation was conducted using the vehicle equipped with the LKAS.

• 임상간호연구
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• 제15권1호
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• pp.19-28
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• 2009

Purpose: The purpose of this study was to examine the effect of position change on discomfort and bleeding in patients undergone coronary angiography with a vascular device and required bed-rest. Method: This study utilized nonequivalent control group non-synchronized design. Data were collected from 118 inpatients after coronary angiography and stayed in general ward at Y hospital in Seoul, from June 5 to August 12, 2008. After coronary angiography, position change was performed to the experimental group who consisted of 59 patients. They stayed in supine position just after angiography and then head-up position with 15 degrees was applied 1 hour later. After that, they could change the position alternatively into lateral position with leg down and supine position. The control group was positioned keeping the affected leg immobile with supine position for 4 hours. Results: The experimental group reported significantly more comfortable than control group after position change. There were no significant differences in the grades of bleeding or hematoma at puncture site between the two groups. Conclusion: The position change in patients undergone angiography could be applied without any harm such as bleeding or hematoma, but effective in reducing back pain and subjective patients' discomforts.

• 대한물리치료과학회지
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• 제25권1호
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• pp.1-10
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• 2018

Background: The purpose of this study was to ascertain the effects of core program exercise on balance in patients with chronic low back pain. Thirty-four subjects participated in this study, these subjects were assigned into two groups, a control group(n=17) and an experimental group(n=17). Methods: The subjects in the control group were received a conservative physical therapy and in the experimental group carried out the core program exercise for 30 minutes per day, three times a week during 6 weeks. In order to evaluate the progresses of balance ability, corresponding variables were measured at two times, pre and 6th week. The balance ability was assessed using GOOD BALANCE system. The collected data were analyzed by using the paired t-test and ANCOVA. In all statistical analyses, significance level, ${\alpha}$ was set by 0.05. Results: The results of this study were as follows: 1) In the position of left standing eye closed, there were significant difference of Y in the control group and X, Y, V in the experimental group. 2) In the position of right standing eye closed, there were significant difference of Y in the control group and X, Y, V in the experimental group. 3) In the position of dynamic balance 1, there were significant difference APV in experimental groups. 4) In the position of dynamic balance 2, there were significant difference MLV in experimental groups. 5) There were significances between the two group of X, V in static balance and APV in dynamic balance. Conclusion: The above results indicated that a core program exercise improved balance abilities in patients with chronic low back. The further studies should be focused at development of various modified forms of the core program exercise in keeping up the improvement effect of this exercise.

• 한국자동차공학회논문집
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• 제14권6호
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• pp.82-88
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• 2006

The study investigated how an adaptive cruise control system induced behavioral adaptation in drivers using a full-scale driving simulator. Forty drivers with different driving styles participated in the study to compare headway-time, vehicle lateral position variation, and head and eye movement when driving with and without the adaptive cruise control system. Results showed that system induced positive behavioral adaptation by drawing consistency in driving speed and headway-time regardless of the driving styles. However, the results also showed that the drivers' reliance on the system induced negative adaptation including reduced lane keeping ability and reduced attention during driving. As a strategy to prevent negative adaptation, the study proposed information service to drivers with the adaptive cruise control system status and driving environment, and investigated effectiveness of the service. Twelve drivers participated in the experiment to compare headway-time, vehicle lateral position variation and subjective ratings when driving with and without the information service. Results showed that the information service assisted the drivers to maintain safer and more comfortable headway-time without impairing drivers' steering ability.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권3호
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• pp.164-172
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• 2004

This paper presents the comparison results of some kinds of control method in circumstance of eccentric load. The plant to be controlled is a computed tomography(CT) driven by a permanent magnet synchronous motor. In a CT system, many units are attached on the rotationally part of a gantry such as x-ray tube, detector, heat exchanger, and data acquisition unit etc. Therefore keeping many components to balance which have different weight is not easy; this is inescapable problem in the all CT systems. To solve this problem against eccentric load, some kinds of control method have been compared and analysed by using protype CT. From the experimental results it is vilified that the CT drive system with model reference control method indicates higher speed regulation ability regardless of variable eccentric weight and uncertain position, and also in the limit condition of constant eccentric weight and fixed position, the compensation method with sinusoidal form is a strong candidate in view of speed ripple reduction.

• 대한조선학회논문집
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• 제38권2호
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• pp.33-43
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• 2001

드릴쉽과 셔틀탱커등 특수선의 건조가 활발해지면서 정해진 위치에서 장시간 작업해야 할 목적으로 동적 자기위치 유지시스템(Dynamic Positioning System)을 장착하는 선박이 늘어나고 있다. 본 논문에서는 DP 시스템의 구성 요소를 소개하고, 수조에서 실험한 결과를 바탕으로 제어이론과 필터이론에 따른 DP성능을 비교하였다. 실험에 사용한 선박은 10만톤급 드릴쉽으로 모델의 길이가 4m이며, 방향이 고정된 3개의 추진기를 사용하였다. 실험 내용은 명령에 따라 주어진 궤적을 이동하는 능력과 파도가 있는 외란조건에서 원하는 선수각을 유지할 수 있는지를 살펴보았다. 추진력을 구하기 위하여 PID 이론을 적용하였고, 제어게인의 변화에 따른 제어특성을 살펴보았다. 선형운동성분과 계측잡음을 제거하기 위하여 칼만 필터와 디지털 필터를 적용하였고, 각각의 필터성능을 비교 검토하였다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 추계학술대회 논문집
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• pp.232-236
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• 2003

The anchor is laid on seabed and the main engine is worked to against incident environmental loads in typoon. As the main engine is broken down in the storm, the anchor chain is cutted and the vessel is drifted. Although a ship is moored by two point mooring lines to keep the her position, a ship is crashed into a rock because of typoon and the accident of oil spilling may be occured. In this paper, we studied the position-keeping of a ship which is analyized based on the slow motion maneuvering equations considering wave, current and wind. The direct integration method is employed to estimate wave loads. The current forces are calculated by using mathematical of MMG. The two point mooring forces are quasisatatically evaluated by using the catenary equation. The coefficeints of wind forces are modeled from Isherwood’s emperical data and the variation of wind speed is estimated by wind spectrum. The nonlinear motions of a two point moored ship are simulated considering wave, current, wind load in time domain.