State and Perspectives of Underwater Robotics - Role of Laboratory for Underwater Systems and Technologies

The state and perspectives of underwater robotics is presented. The role and achievements of Laboratory for underwater systems and technologies (LABUST) in this domain is described. Two LABUST projects are shortly described

Identifikacija bespilotnih ronilica korištenjem postupka vlastitih oscilacija

Control of underwater vehicles is a challenging task since these systems demonstrate highly coupled and nonlinear behavior in uncertain and often unknown environment. In order to successfully design higher levels of control hierarchy, sufficiently accurate parameters of a mathematical model describing the vessel is required. These parameters vary significantly depending on the payload; hence conventional, time-consuming identification methods are tedious. This paper introduces a self-oscillation based method for determining inertia and drag parameters for underwater vehicles. The procedure is easily implementable in field conditions and gives satisfactory results. Both linear and nonlinear models of yaw, heave and surge degree of freedom can be identified. Experimental results obtained from yaw identification experiments on a real underwater vehicle will be presented. In addition to this, the same methodology will be used to determine which model describes the vehicle dynamics more suitably. Modifications of the proposed algorithm for systems with delays and discrete-time systems will be described, together with an estimate of parameter error bounds due to quantization levels.Upravljanje bespilotnim ronilicama predstavlja zahtjevan zadatak budući da ronilice pokazuju snažno spregnuto i nelinearno ponašanje u nepredvidljivim i često nepoznatim okruženjima. U svrhu uspješnog projektiranja viših razina u njihovoj upravljačkoj hijerarhiji, potrebno je dovoljno dobro poznavati parametre matematičkog modela plovila. Ovi se parametri mogu znatno mijenjati ovisno o opremi i drugim uvjetima tijekom misije, stoga su uobičajeni, vremenski zahtjevni identifikacijski postupci neprikladni. Članak opisuje postupak koji koristi vlastite oscilacije za određivanje inercije i otpornosti bespilotnih ronilica. Postupak je lako primjenjiv u terenskim uvjetima i daje zadovoljavajuće rezultate. Linearan i nelinearan model zaošijanja, zaranjanja i napredovanja mogu´ce je identificirati. U radu su prikazani eksperimentalni rezultati dobiveni na identifikacijskim ekperimentima zaošijanja na stvarnoj ronilici. Uz navedeno, ista metodologija je iskorištena za odlučivanje o modelu koji prikladno opisuje stvarnu ronilicu. U radu su opisane i preinake predloženog algoritma za sustave s transportnim kašnjenjem i diskretne sustave, kao i procjene pogrešaka u određivanju parametara koje su posljedica kvantizacije

3D Line Following for Unmanned Underwater Vehicles

When designing guidance controllers for unmanned underwater vehicles, an assumption is often made that the vessel operates at a constant depth. However, in many applications the desired depth often changes with the position of the vessel in the horizontal plane. This paper addresses the problem of three dimensional line following with the application to underactuated underwater vehicles. The problem is resolved by separating the desired line into two components. The main contribution of this paper is the design of 3D line following controllers for underactuated underwater vehicles. The control design is based on constant controlled surge speed and a simplifi ed decoupled model of an under water vehicle. Detailed design procedure is presented. The simulation results are obtained from a complex, coupled model, which proves that the proposed algorithm can be used on real vehicles

Application of an ASV for Coastal Underwater Archaeology

Coastal underwater archaeological sites are by nature dynamic, and often subject to disturbance from the action of waves, currents, sediment, and human activity. The need to document such sites comprehensively, accurately, and quickly has been the driving force behind technological advances in predisturbance site mapping since the 1960s. Certain challenges remain constant: the need for technology to be affordable and robust, with efficient post-processing as well as data acquisition times. Non-engineers must be able to interpret the results and publish them according to archaeological conventions. Large ancient shallow water port sites, submerged settlements, and landscape surveys present additional difficulties because of the volume of data generated. In this paper we present results of two expeditions to map the submerged Herodian structures at Caesarea Maritima, Israel, using a robotic vehicle, the Autonomous Surface Vehicle (ASV) Pladypos, which was developed to address these challenges. This vehicle carries high-resolution imaging and remote-sensing tools to produce photomosaics and microbathymetry maps of the seafloor, as well as performing precise geo-referencing. The results were later integrated into a GIS

Application of Heterogeneous Robotic System for Underwater Oil Spill Scenario

The tragic Deepwater Horizon accident in the Gulf of Mexico in 2010 as well as the increase in deepwater offshore activity have increased public interest in counter-measures available for subsurface releases of hydrocarbons. To arrive at proper contingency planning, response managers urge for a system for instant detection and characterization of accidental releases. Along these lines, this paper describes the application of a heterogeneous robotic system of unmanned vehicles: autonomous underwater vehicle (AUV), unmanned surface vehicle (USV) and unmanned aerial vehicle (UAV) extended with the oil spill numerical modeling, visualisation and decision support capabilities. A first set of field experiments simulating oil spill scenarios with Rhodamine WT was held in Croatia during the early autumn 2014. and the second set of experiments were held in Spain during the summer 2015. The objectives of this experiment were to test: effectiveness of the system for underwater detection of hydrocarbons, heterogeneous multi-vehicle collaborative navigation and communication as well as decision support system, visualisation of the system components and detected spill

Augmented Reality in Marine Applications

Augmented reality (AR) system combines the real world with virtual information and provides expanded and information-rich view of the environment to the user. The AR systems have been around for a few decades but their number started to grow signifi cantly only during the past few years. Recent advances in technology, lower cost of otherwise expensive equipment and especially development of the smart handheld-device market have propelled the rapid development of the AR. It has literally become a part of everyday life. This paper presents a systematic overview of AR technology. It covers AR system components, applications, outlook on future research and development as well as main technology challenges and limitations. The paper also includes several examples of Virtual Reality (VR), the technology similar to the AR, as well as existing and potential AR and VR applications in maritime sector

Karakteristike asinhrone mašine sa dvostranim napajanjem i primena za korišćenje energije vetra

This paper presents the characteristics of an asynchronous machine with winded rotor, fed both from stator and from rotor side. Mathematical model and the equivalent circuit of this mode of asynchronous machine’s work are defined and expressions for characteristic values are derived. On the basis of the obtained characteristics it is pointed out that this kind of electrical machines, while working in generating mode, may be used in systems where electric power is generated from wind energy. Main characteristics of wind turbine – doubly-fed asynchronous machine system are processed.U radu su date karakteristike asinhrone mašine sa namotanim rotorom koja se napaja i sa strane statora i sa strane rotora. Definisani su matematički model i ekvivalentna šema ovog režima rada asinhrone mašine i izvedeni su izrazi za karakteristične veličine. Na osnovu dobijenih karakteristika ukazano je na mogućnost korišćenja ove vrste električnih mašina, kada rade u generatorskom režimu rada, u sistemima za generisanje električne energije iz energije vetra i obrađene su osnovne karakteristike sistema vetroturbina – asinhrona mašina sa dvostranim napajanjem

Characteristics of female drinking by age

Alcohol dependence in women is a problem in the contemporary society. The change of the traditional woman’s role is accompanied by an increasing rate of women who abuse alcohol. It is therefore necessary to create treatment and preventive interventions adjusted to this population. Alcoholism in women differs greatly according to age groups. Adolescents, young females, middle-aged women and older women have different etiological factors underlying their drinking problem. The characteristics and the drinking habits also differ greatly in young and older women. For the period of adolescence, the most important risk factors are behavioral problems, problems at school and family history and environment. For women in young adulthood, the most important risk factors are problems associated with the role and health problems. For the women of older age, the most important are widowhood and retirement issues. This article shows that the likelihood of developing alcoholism increases as the risk factors become more numerous. The above risk factors suggest the connection with the development of alcohol dependence but do not prove causality

Konstrukcija, karakteristike i primena u poljoprivredi elektromagneta za magnetnu obradu vode

This paper presents the characteristics of a special, transformer-type electromagnet MOV - 2 that can be used in the magnetic treatments of water, for the purpose of its further use in various fields of science, industry, agriculture and medicine. This electromagnet is the original technical solution. Its construction makes it possible to obtain high values of magnetic induction, to regulate magnetic field parameters and continuously adjust the length of the air-gap in which a tube containing water which is treated magnetically is placed. The use of magnetized water is applied to the field of agriculture.U radu su date karakteristike specijalnog elektromagneta transformatorskog tipa MOV – 2 za magnetnu obradu vode radi njene dalje upotrebe u raznim oblastima nauke, industrije, poljoprivrede i medicine. Elektromagnet je originalno tehničko rešenje koje svojom konstrukcijom omogućava dobijanje visokih vrednosti magnetne indukcije, regulaciju parametara magnetnog polja i kontinualno podešavanje optimalne dužine vazdušnog zazora u kome se nalazi cev sa vodom koja se magnetno obrađuje. Primena magnetisane vode konkretizovana je na oblast poljoprivrede

Characteristics of female drinking by age

Alcohol dependence in women is a problem in the contemporary society. The change of the traditional woman’s role is accompanied by an increasing rate of women who abuse alcohol. It is therefore necessary to create treatment and preventive interventions adjusted to this population. Alcoholism in women differs greatly according to age groups. Adolescents, young females, middle-aged women and older women have different etiological factors underlying their drinking problem. The characteristics and the drinking habits also differ greatly in young and older women. For the period of adolescence, the most important risk factors are behavioral problems, problems at school and family history and environment. For women in young adulthood, the most important risk factors are problems associated with the role and health problems. For the women of older age, the most important are widowhood and retirement issues. This article shows that the likelihood of developing alcoholism increases as the risk factors become more numerous. The above risk factors suggest the connection with the development of alcohol dependence but do not prove causality