• 수산해양기술연구
• /
• 제54권3호
• /
• pp.231-238
• /
• 2018

In this study, a ship motion control system design method is introduced for autonomous ships. Some related research results and technologies for autonomous ships have already been developed and applied to ships. For example, the Norwegian Maritime Authority and the Coastal Administration have signed an agreement that allows to test of autonomous ships in the defined area (port to port). Many countries and industries are pursuing to realize the autonomous vessel in the real world. In this paper, the authors try to develop related technology. As basic research, a ship model of the pilot vessel is developed and physical parameters are identified by experiment and simulations. Using the mathematical ship model, a control system is designed and control performance is evaluated by simulations.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.417-420
• /
• 2004

Recently, the applications of unmanned system are steadily increasing. Unmanned automatic system is suitable for routine mission such as reconnaissance, environment monitoring, resource conservation and investigation. Especially, for the ocean environment monitoring mission, many ocean engineers had scoped with the routine and even risky works. The automatic system can replace the periodic and routine missions: water sampling, temperature and salinity measuring, etc. In this paper, an unmanned surface vessel was designed for routine and periodic ocean environmental missions. An autonomous control system was designed and tested for the unmanned vessel. A GPS and gyro compass was used for navigation. A linear autopilot model for course control can be derived from the maneuvering model. Nomoto's 2nd-order response equation was derived. The design methodologies and performance of the surface vessel were illustrated and verified with this linearized equation of motion. A linear controller was designed and automatic route tracking performance was verified for yaw subsystem.

• Nuclear Engineering and Technology
• /
• 제53권2호
• /
• pp.532-548
• /
• 2021

Nuclear power plants contain several monitoring systems that can identify the in-vessel phenomena of a severe accident (SA). Though a lot of analysis and research is carried out on SA, right from the development of the nuclear industry, not all the possible circumstances are taken into consideration. Therefore, to improve the efficacy of the safety of nuclear power plants, additional analytical studies are needed that can directly monitor severe accident phenomena. This paper presents an interacting multiple model (IMM) based fault detection and diagnosis (FDD) approach for the identification of in-vessel phenomena to provide the accident propagation information using reactor vessel (RV) out-wall temperature distribution during severe accidents in a nuclear power plant. The estimation of wall temperature is treated as a state estimation problem where the time-varying wall temperature is estimated using IMM employing three multiple models for temperature evolution. From the estimated RV out-wall temperature and rate of temperature, the in-vessel phenomena are identified such as core meltdown, corium relocation, reactor vessel damage, reflooding, etc. We tested the proposed method with five different types of SA scenarios and the results show that the proposed method has estimated the outer wall temperature with good accuracy.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2021년도 추계학술대회
• /
• pp.18-20
• /
• 2021

최근 증가하고 있는 선박의 충돌 사고 예방을 위하여 인공지능 기반의 자율운항선박(Maritime Autonomous Surface Ship, MASS)에 관한 연구가 진행되고 있다. 하지만 대부분의 자율운항선박 관련 연구들은 자율운항시스템의 크기와 비용으로 인해 주로 중대형 선박을 그 대상으로 하고 있으며, 여기에 사용되는 센서들은 소형선박에 탑재하기 어렵다는 문제를 지닌다. 따라서 이 논문은 소형선박의 자율운항을 위하여 GPS와 IMU 센서를 탑재한 경로 추적 시스템을 제안한다. GPS와 IMU 센서는 선박의 정확한 위치 파악을 위하여 활용되며, 이를 통하여 제안 시스템은 소형선박 모형을 수동으로 제어하여 경로를 생성하고, 이후 소형선박이 동일한 경로를 이동할 시 Pure Pursuit 알고리즘을 이용하여 경로를 추적하도록 한다. 그 결과, 이 연구는 경량화된 저가의 센서들을 이용하여 소형 선박의 자율운항 시스템을 저비용으로 개발할 수 있을 것으로 기대된다.

• 한국항해항만학회지
• /
• 제47권6호
• /
• pp.430-436
• /
• 2023

자율운항선박 관련 기술개발은 2010년도 중반부터 충돌회피, 항로 지정, 디지털 트윈 및 통신 기술개발 등의 주제로 활발하게 진행되고 있다. 그러나, 이와 비교하여 자율운항선박과 연계된 물류시스템, 항만시설 및 선박교통관제 등의 육상 인프라에 관한 연구는 상대적으로 관심을 받지 못하고 있다. 이 연구에서는 자율운항선박의 등장에 따라 기존 선박교통관제 업무에 미치게 되는 영향을 분석함과 동시에 이를 대비하기 위한 관제 업무 변화 방안을 제시하였다. 이를 위하여 현행 선박교통관제 업무를 분석하고, 동시에 자율운항선박 기술 중 선박교통관제에 영향을 미칠 수 있는 요소를 파악하였다. 또한, 선박교통관제사들을 대상으로 자율운항선박 관제 관련 항목 도출을 위한 설문조사를 수행하였으며, 이를 AHP 기법으로 분석한 결과 비상 상황 대응 및 자율운항선박과의 통신 방법에 대한 준비가 가장 중요한 것으로 도출되었다. 이를 기반으로 해상교통관제구역 내에서 데이터 통신을 기반으로 한 기본적인 자율운항선박 관제 절차 및 비상 대응 절차 등 세부 방안을 도출할 수 있었다. 이 연구에서 제안하는 자율운항선박 관제 절차는 향후 자율운항선박의 연안 해상교통안전에 관한 문제점들을 해소하는 방안으로 활용될 수 있을 것으로 기대된다.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제7권5호
• /
• pp.817-832
• /
• 2015

This paper presents a state feedback based backstepping control algorithm to address the trajectory tracking problem of an underactuated Unmanned Surface Vessel (USV) in the horizontal plane. A nonlinear three Degree of Freedom (DOF) underactuated dynamic model for USV is considered, and trajectory tracking controller that can track both curve trajectory and straight line trajectory with high accuracy is designed as the well known Persistent Exciting (PE) conditions of yaw velocity is completely relaxed in our study. The proposed controller has further been enriched by incorporating an integral action additionally for enhancing the steady state performance and control precision of the USV trajectory tracking control system. Global stability of the overall system is proved by Lyapunov theory and Barbalat's Lemma, and then simulation experiments are carried out to demonstrate the effectiveness of the controller designed.

• 한국해양공학회지
• /
• 제19권1호
• /
• pp.95-99
• /
• 2005

This paper presents the optimum design of cylindrical shell under external pressure loading. Two kinds of material, Al7075-T6, Ti-6Al-4V, are considered. For each material, the design variable is a thickness of the unstiffened parallel middle body shell, and the state variable, constraint, is hoop stress and the object .function is total weight of the cylindrical shell. Optimization is performed by conventional FE Program, ANSYS. In addition, buckling analysis is performed for the middle body of the cylindrical shell. Finally, we calculates the payload of the cylindrical shell to keep neutral buoyancy with optimized thickness in deep-sea applications.

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2002년도 추계학술대회 논문집
• /
• pp.34-39
• /
• 2002

A Semi-Autonomous Underwater Vehicle (SAUV) capable of simple work at sea bed is under development in KRISO-KORDI. A pressure vessel of SAUV which is composed of FRP was manufactured to load electronic equipments. The objective of this paper is to verify the safety of the pressure vessel through conducting the structural analysis and test in pressure tank. Strain and stress under unit load were obtained by using ANSYS in the linear structural analysis. And local buckling analysis was performed with NASTRAN for the middle cylindrical hull. For the pressure test, strains were measured at three point. We found that the results by linear structural analysis and experiment are coincide well at the points where buckling does not occur. Maximum depth was estimated to be 250m by the local buckling analysis.

• 한국해양공학회지
• /
• 제18권4호
• /
• pp.52-58
• /
• 2004

A Semi-Autonomous Underwater Vehicle (SAUV), capable of simple work on the seabed, is under development in KRISO-KORDI. This SAUV pressure vessel is composed of fiberglass reinforced plastic (FRP), and is also manufactured to carry electronic equipment. The objective of this paper is to describe the safety check for the pressure vessel. This is achieved fly conducting structural analysis and testing in a pressure tank. Strain and stress test results, under unit load, are obtained fly using ANSYS in linear structural analysis. Local buckling analysis are performed with NASTRAN at the middle oj the cylindrical hull. The first test, using linear structural analysis, is unsuccessful, as buckling occurred. During the second test, linear structural analysis, combined with local buckling analysis, is conducted. There is no buckling up to 250 m when both ANSYS and NASTRAN are used.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2020년도 추계학술대회
• /
• pp.54-55
• /
• 2020

4차 산업혁명으로 인공지능, 사물인터넷, 빅데이터 등의 기술이 조선 해운 산업에 매우 밀접하게 연관 되고 있고 이는 자율운항선박의 탄생을 가져왔다. 현재 선박의 기술적 특성상 속력을 갑자기 낮출 수 없으므로 항만에 접안하기 위해 예인선의 도움, 도선사의 승선, 육상관제센터의 선박 컨트롤 등 복잡한 커뮤니케이션을 필요로 한다. 본 연구에서는 자율운항선박이 도입될 경우 선박이 입항하기 위한 컨트롤 기준을 어떻게 설정할지 해결하고자 클러스터링 분석을 사용하였다. 입항 선박의 축적된 AIS 데이터를 기반으로 입항 패턴을 정량적으로 단계화하고자 K-Means 클러스터링을 사용했고 SOG(Speed over Ground), COG(Course over Ground), ROT(Rate of Turn)를 사용하여 입항 단계를 6개로 구분하였다.