This thesis describes a vision-based method for ROV¡¦s underwater pipeline recognition task. In this research, we tried to overcome the poor image quality of the underwater circumstance and the condition when seaweed is in the scene. Edge information and line feature of the pipeline are used in this method. Edge image is obtained after preprocessing to extract line feature. In this thesis we focused on the recognition of pipeline, trying to provide useful navigation information for further development of the ROV¡¦s control system.

No description available.

Remotely Operated underwater Vehicles (ROVs) are getting more and more advanced withevery new model. As new functionality is added, the price increases. This thesis is one partof a larger project, where the goal is to develop a low-budget ROV. The ROV should later bemade autonomous and entered into a competition.This thesis have focused on the modeling and stabilizing control of an ROV that was designedby mechanical engineering students at Linköping University. The only sensor used was anInertial Measurement Unit (IMU) and the ROV has a torpedo-like design. The modeling wasdone using identification in Matlab with the grey box and black box methods. Water trialsand simulations show that the model is estimated sufficiently good to be used as the basis ofdifferent model based controllers.Two different control strategies were implemented; a linear quadratic controller (LQ) and amodel predictive controller (MPC). Both controllers worked desirably in simulations. Onlythe LQ controller was evaluated in real world tests. Due to problems with the implementationenvironment chosen for the MPC, the MPC could not be tested.The thesis also uses decision matrices as a mean to motivate the important decisions thathave been made.

Remotely operated vehicle (ROV) dynamics is affected by hydrodynamic forces such as added mass and viscous drag force. Both of added mass and drag force coefficients can be measured by a set of Planar Motion Mechanism (PMM) tests; however, it is costly. In this study, an economic method for identifying hydrodynamic parameters of ROV is given. A simplified nonlinear ROV dynamics model with twelve unknown hydrodynamic parameters in six degrees of freedom was derived for simulations. The identification is based on experimental data obtained by projective mapping method which is utilized to measure the planar motions of a ROV. Then least-squares optimization is performed by comparison between the theoretical simulations and the actual motion measurements. But, an optimization computation involving a large number of parameters is likely to get trapped in a local minimum. Therefore, to reduce the number of parameters to be optimized, some models of simple motions such as surge, sway, surge and sway, yaw, and heave are decoupled from the ROV dynamic model. A commercial ROV ¡§Seamor¡¨ that equipped with two vertical thrusters, two horizontal thrusters, and a depth sensor is used for identification. The experiments for measuring ROV motions of surge, sway, surge and sway, and yaw were performed in a swimming pool in National Sun Yat-sen University. A video camera is utilized to capture ROV for position estimation using projective mapping method. As for the heave motion of ROV, the experiment was conducted offshore the Shio-Liu-Qiu Island and the ROV depth was measured by an onboard pressure sensor. Then, optimal hydrodynamic parameters are identified in sequence of surge, heave, yaw, sway, and then surge and sway. Verification experiments were performed and the simulation results with the optimum values of hydrodynamic parameters show good agreement with the measured data from verification experiments.

Conventionally, pilots control ROV (Remotely Operated Vehicle) with on-board console connected to the vehicle with a power/signal tether. For those who want to operate the vehicle or observe the underwater scenery would need to sit right by the console. Operation of the vehicle or the real time data acquired by vehicle's sensors is not possible or available for the scientist who is not on-board. Recently, there has been a vast development and application of Internet technology on both new emerging fields and conventional fields as well. This motivates us to design an Internet-based man-machine interface to overcome the aforementioned limits. We choose Java to be the core language for its excellency in communication, security, portability and graphics user interface (GUI). On the other hand, Java suffers from lacking the interface to do low level access to the hardware of the computer. This means that Java can not accomplish hardware control by itself. However, this limitation can be removed by including JNI (Java Native Interface) which provides a protocol for Java to communicate with DLL written in C. Security is also a major concern of Internet-based applications. We use Java's built-in security package to carry out "Message Digest" computation for the login authentication. Different level of privileges are given to the users according to their user name and password. So any user who has access to Internet can use internet browser (Microsoft IE or Netscape) to control the system remotely. In this thesis, we use a CCD camera mounted on a stepping motor to represent the whole ROV system. Different subject users over the TANET, including NTOU in Keelung, ME and IUT NSYSU in Kaohsiung, are tested. We find that under the current internet infrastructure in Taiwan, our system can deliver as least one 160x120 24-bit color frame every 2 seconds or so. Control commands for the stepping motor experiences no significant delay. This preliminary result indicates a similar structure can be adopted in developing I.A (Information Appliance).

Vid årsskiftet 2013-2014 lanserade Ocean Robotics International en undervattensfarkost med främsta syfte att filma och samla in data under ytan. För att farkosten ska kunna operera tyngdlöst i vattnet används ett flytmaterial vars utformning uppnår väldigt höga tillverkningskostnader. Därför finns det efterfrågan ifrån företaget att utveckla en farkost bättre anpassad för produktion, för att på så sätt möjliggöra minskade produktionskostnader.  Dessutom har företagets huvudsakliga kunder angett nya krav och önskemål på produkten, som kräver ett nytt utförande på farkosten för att uppnå kravuppfyllelse. Syftet med detta arbete är att göra en vidareutveckling av undervattensfarkosten som uppfyller nya krav och önskemål, samt är produktionsanpassad. Målet är att ta fram produktionsunderlag till den framtagna farkosten. Arbetet följde en generell, etablerad produktutvecklingsmodell av Ulrich och Eppinger (2008), som innefattade upprätthållande av en kravspecifikation, en konceptgeneringsfas med kombinerade strukturerade och fria metoder samt konceptval. Arbetsmodellen kompletterades med DFMA (Design for Manufacturing and Assembly); teori kring hur produkter kan tas fram för att anpassas för produktion. I arbetet undersöktes olika sätt att skapa flytkraft varvid de flesta tekniker bygger på principen inkapslad luft. På 3000 meters djup, som farkosten är utformad att operera på, är trycket ungefär 300 gånger atmosfärstrycket. Detta skapar problem för många sådana konstellationer på grund av den höga tryckskillnad som bildas mellan den inkapslade luften och det omgivande vattnet. Därför föll valet på syntaktiskt skum som företaget använder sedan tidigare, ett material med lägre densitet än vatten och som därmed avger flytkraft. Materialet är väl lämpat för avsett djup. Stabilitet i farkosten är ytterligare en faktor som är av viktigt att ta hänsyn till vid utformning, eftersom det starkt påverkar hur enkel den är att operera med. Rätt förutsättningar fås av när flytmaterial är väl utspritt i farkosten, stora avstånd mellan motorerna och farkostens form då en avlång konstruktion är att föredra. En långsmal farkost med avrundade kanter ger även fördelar i strömningsförmåga. Arbetet resulterade i ett koncept i detaljutförande och produktionsunderlag. För att uppfylla de nya kraven är farkosten större än föregående modell. Formerna på flytblocken är kraftigt förenklade för att på så sätt undvika maskinbearbetning som är en kostsam process. Där det är önskvärt med dubbelkrökta ytor har dessa istället skapats med hjälp av kåpa bestående av glasfiber, som tillverkas genom kompositlaminering som är en metod väl lämpad för att skapa organiska former. / At the turn of 2013-2014, Ocean Robotics International launched an underwater vehicle with the main purpose of filming and collecting data under the surface. In order to make the vehicle operate weightlessly in the water, buoyant material is used but unfortunately the manufacturing costs to produce the shape in this material is very high. Therefore, there is a request from the company to develop a vehicle which will enhance the manufacturing and expectantly reduce the production cost. In addition, the company's main customers have expressed new requirements of the product, which entail a new version of the vehicle in order to meet those requests. The purpose of this work is to make a further development of the underwater vehicle that meet the new demands and requirements, and is adapted for production. The goal is to provide production documentation for the developed vehicle. The work structure followed a general, established model of product development by Ulrich and Eppinger (2008), and included the maintenance of a requirements specification, concept generation including structured as well as unstructured methods and concept selection. The working model was complemented with DFMA (Design for Manufacturing and Assembly); theory regarding designing products suited for production. In the project an investigation was made of different ways to create buoyancy; most techniques are based on the principle of encapsulated air. The vehicle is designed to operate at the depth of 3000 meters under the surface of the water, where the pressure is approximately 300 times the atmospheric pressure.  This creates problems for several of such techniques due to the high pressure difference between the encapsulated air and the ambient water. Therefore, syntactic foam was chosen for the purpose which the company already uses, a material with a lower density than water which therefore creates buoyancy. The material is well suited for the intended depth. Stability of the vehicle is another factor that is important in design consideration, since it strongly influences the easiness of the operation. Right conditions are obtained by buoyant material well spread out around the vehicle, a large distance between the thrusters and furthermore an elongated form of the vehicle is preferable. A long and narrow vehicle with rounded edges also offers advantages in flow capacity. The work resulted in detail design of a concept and production documentation. To meet the new requirements, the vehicle is larger than the previous model. The shapes of the floating blocks are to a great extent simplified to avoid machining, which is a manufacturing process of high cost. Where it is desirable with double curved surfaces, bodywork of glass fiber is used, made by composite lamination – a method well suited for creating organic shapes.

O objetivo deste trabalho foi caracterizar os hábitats bênticos do Banco de Abrolhos e comparar dois tipos de recife no local: rasos e mesofóticos. Foram feitas filmagens com um ROV em 20 estações ao redor do Banco para um estudo em mesoescala. Para a comparação dos recifes, foram feitas filmagens nos recifes rasos de Sebastião Gomes e Parcel dos Abrolhos e na área mesofótica de Itacolomis. As imagens foram analisadas através do programa CPCe®. Foram calculadas a abundância total das espécies por área e por estação e os índices de diversidade e equitabilidade. As estações foram comparadas através do cálculo da similaridade de Bray Curtis e de uma análise fatorial de correspondência (AFC). Nas estações ao redor do Banco foi constatado uma extensa área de rodolitos na parte externa e áreas de fundo inconsolidado na região mais interna. Os bancos de rodolito ocorreram sempre em profundidades maiores que 30 metros. Nos recifes rasos houve uma dominância de macroalgas (ca. 23%), octocorais (ca. 16%) e zoantídeos (ca. 14%), sendo sempre mais diversos que os bancos de rodolitos. O recife mesofótico de Itacolomis teve cobertura predominantemente rodolítica (ca. 48%). Dentre os outros organismos encontrados, os mais abundantes foram macroalgas (ca. 17%) e esponjas (ca. 4%). Abrolhos é o ecossistema mais rico do Atlântico Sul e se encontra severamente ameaçado. Pouco se conhece ainda sobre seu funcionamento e sobre suas áreas mais profundas. Estudos como este são necessários para entender e conservar o Banco de Abrolhos. / The benthic habitats of Abrolhos Bank were characterized and two kind of reefs were compared: shallow and mesophotic. Video footage was taken in 20 sites on the Bank using an ROV. Other footages were taken on the shallow reefs Sebastião Gomes and Parcel dos Abrolhos and at the mesophotic Itacolomis to make the comparison. Still images from videos were analyzed using the CPCe® program. We calculated the total abundance, diversity and equitability of epibenthic species. We also compared the sites using the similarity index of Bray Curtis and a correspondence analysis (CFA). Large rhodolith beds were found on the Bank edges, with inner sites composed mainly by soft bottoms. Rhodolith beds were always found at depths greater than 30 meters. At the shallow reefs macroalgae (ca. 23%), octocorals (ca. 16%) and zoanthids (ca. 14%) dominated. These sites presented higher epibenthic diversity than rhodolith beds. Rhodoliths dominated in the mesophotic area of Itacolomis reef with ca. 48% coverage. Other abundant organisms were macroalgae (ca. 17%) and sponges (ca. 4%). Abrolhos is the richest ecosystem in the South Atlantic ocean and it is severely threatened. There is still little information available, specially for the deeper zone. More researches like the one presented herein are very important and necessary to understand and conserve Abrolhos Bank.

O objetivo deste trabalho foi caracterizar os hábitats bênticos do Banco de Abrolhos e comparar dois tipos de recife no local: rasos e mesofóticos. Foram feitas filmagens com um ROV em 20 estações ao redor do Banco para um estudo em mesoescala. Para a comparação dos recifes, foram feitas filmagens nos recifes rasos de Sebastião Gomes e Parcel dos Abrolhos e na área mesofótica de Itacolomis. As imagens foram analisadas através do programa CPCe®. Foram calculadas a abundância total das espécies por área e por estação e os índices de diversidade e equitabilidade. As estações foram comparadas através do cálculo da similaridade de Bray Curtis e de uma análise fatorial de correspondência (AFC). Nas estações ao redor do Banco foi constatado uma extensa área de rodolitos na parte externa e áreas de fundo inconsolidado na região mais interna. Os bancos de rodolito ocorreram sempre em profundidades maiores que 30 metros. Nos recifes rasos houve uma dominância de macroalgas (ca. 23%), octocorais (ca. 16%) e zoantídeos (ca. 14%), sendo sempre mais diversos que os bancos de rodolitos. O recife mesofótico de Itacolomis teve cobertura predominantemente rodolítica (ca. 48%). Dentre os outros organismos encontrados, os mais abundantes foram macroalgas (ca. 17%) e esponjas (ca. 4%). Abrolhos é o ecossistema mais rico do Atlântico Sul e se encontra severamente ameaçado. Pouco se conhece ainda sobre seu funcionamento e sobre suas áreas mais profundas. Estudos como este são necessários para entender e conservar o Banco de Abrolhos. / The benthic habitats of Abrolhos Bank were characterized and two kind of reefs were compared: shallow and mesophotic. Video footage was taken in 20 sites on the Bank using an ROV. Other footages were taken on the shallow reefs Sebastião Gomes and Parcel dos Abrolhos and at the mesophotic Itacolomis to make the comparison. Still images from videos were analyzed using the CPCe® program. We calculated the total abundance, diversity and equitability of epibenthic species. We also compared the sites using the similarity index of Bray Curtis and a correspondence analysis (CFA). Large rhodolith beds were found on the Bank edges, with inner sites composed mainly by soft bottoms. Rhodolith beds were always found at depths greater than 30 meters. At the shallow reefs macroalgae (ca. 23%), octocorals (ca. 16%) and zoanthids (ca. 14%) dominated. These sites presented higher epibenthic diversity than rhodolith beds. Rhodoliths dominated in the mesophotic area of Itacolomis reef with ca. 48% coverage. Other abundant organisms were macroalgae (ca. 17%) and sponges (ca. 4%). Abrolhos is the richest ecosystem in the South Atlantic ocean and it is severely threatened. There is still little information available, specially for the deeper zone. More researches like the one presented herein are very important and necessary to understand and conserve Abrolhos Bank.

Background Maritime transportation is vital for international trade, and any disruption to this flow can have severe financial and environmental consequences. Ship mines, both old and new, present significant risks as man-made obstacles. The perilous task of minesweeping, historically carried out by humans at great risk, necessitates the development of unmanned vessels. These autonomous solutions aim to effectively address the dangers posed by ship mines while ensuring the safety of human lives. Objectives This thesis aims to explore the potential of next-generation Mine countermeasure vessel (MCMV) and develop a concept for an autonomous or remotely operated vessel capable of effectively clearing sea mines. This thesis is limited to only considering surface vessels for the MCMV, and alternative designs like submersible vehicles are not considered. Furthermore, the study relies on conventional platform technology, potentially limiting the vehicles’ capabilities compared to emerging technologies. Methods The methodology employed in this degree project is centered on the analysis of current trends and technologies in Mine countermeasure (MCM) operations. Three world-leading products in the field are described in depth to then go through a comprehensive evaluation to serve as a foundation for concept development. Results The outcome of this thesis is a catamaran-based concept that incorporates additional functionalities to enhance its adaptability and self-defense capabilities. The concept extends upon the design of an existing product, incorporating new features such as adjustable width and the ability to support forward reconnaissance, as well as contribute to air defense capabilities within the fleet. Conclusions The future of MCM operations is expected to shift towards automated systems, characterized by smaller and more affordable platforms. This technological advancement enables the increased deployment of MCMVs, with their effectiveness being determined by the number of units rather than individual speed. As technological developments in marine environments continue to progress, the significance of ensuring safety and control in these settings becomes of utmost importance. AutonomousMCMVs will play a vital role in addressing these challenges and contribute significantly to the safety and security of marine environments in the future. / Bakgrund Sjötransporter är avgörande för internationell handel, och störningar i detta flöde kanfå allvarliga ekonomiska och miljömässiga konsekvenser. Fartygsminor, både gamlaoch nya, utgör betydande risker. Uppgiften med att röja dessa hinder, har historisktutförd av människor innebärandes stora risker. Detta har drivit på utvecklingen avobemannade fartyg. Dessa autonoma lösningar syftar till att effektivt ta itu medfarorna som fartygsminor utgör samtidigt som de garanterar människors säkerhet. Syfte Detta examensarbete syftar till att utforska potentialen hos nästa generations MCMVoch utveckla ett koncept för ett autonomt eller fjärrstyrt fartyg som effektivt kanröja sjöminor. Antagandet görs att MCMV antingen kommer att vara autonomeller fjärrstyrd, och alternativa konstruktioner som undervattensfordon övervägs inte.Dessutom bygger studien på nyttjande av konventionell plattformsteknik, vilket po-tentiellt begränsar fordonens kapacitet jämfört med framtida tekniker. Metod Metodiken som används i detta examensarbete är centrerad på analys av aktuellatrender och teknologier i MCM-området. Tre världsledande produkter inom områdetbeskrivs ingående för att sedan gå igenom en omfattande utvärdering, resultatet nyt-tjas för att ligga till grund för konceptutvecklingen. Resultat Resultatet är ett katamaranbaserat koncept som innehåller ytterligare funktioner föratt förbättra dess anpassnings- och självförsvarsförmåga. Konceptet utgår från ut-formningen av en befintlig produkt, med nya tillförda funktioner som justerbar breddoch förmågan att aggera som framskjuten spaning, samt bidra till luftförsvarska-paciteten inom flottan. Slutsatser Framtiden för MCM-verksamheten förväntas skifta mot automatiserade system, kän-netecknade av mindre och mer prisvärda plattformar. Denna tekniska utvecklingmöjliggör byggnation av fler MCMV, där effektiviteten snarare bestäms av antaletenheter än fartygens hastighet. När exploateringen i marina miljöer fortsätter, blirbetydelsen av säkerhet och kontroll i dessa miljöer av yttersta vikt. AutonomaMCMV kommer att spela en viktig roll för att hantera dessa utmaningar.

Examensarbetet utvärderar undervattensfarkosten Stursk som byggts av studenter på Linköpings universitet och förbättrar sedan ett flertal komponenter på farkosten, samt lämnar förslag på framtida förbättringar. Rapporten behandlar motorkapslingen, lyftpunkterna, strömbrytaren, elektroniken, tryckskrovet, varvtalsmätning, tryckgivare och viktigast av allt, granskar farkostens manövreringsförmåga närmare.