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Wyświetlanie 1-15 z 39
Tytuł:
Correction of navigational information supplied to biomimetic Autonomous Underwater Vehicle
Autorzy:
Praczyk, T.
Powiązania:
https://bibliotekanauki.pl/articles/259696.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
underwater navigation
odometry
underwater vehicle
Opis:
In order to autonomously transfer from one point of the environment to the other, Autonomous Underwater Vehicles (AUV) need a navigational system. While navigating underwater the vehicles usually use a dead reckoning method which calculates vehicle movement on the basis of the information about velocity (sometimes also acceleration) and course (heading) provided by on-board devicesl ike Doppler Velocity Logs and Fibre Optical Gyroscopes. Due to inaccuracies of the devices and the influence of environmental forces, the position generated by the dead reckoning navigational system (DRNS) is not free from errors, moreover the errors grow exponentially in time. The problem becomes even more serious when we deal with small AUVs which do not have any speedometer on board and whose course measurement device is inaccurate. To improve indications of the DRNS the vehicle can emerge onto the surface from time to time, record its GPS position, and measure position error which can be further used to estimate environmental influence and inaccuracies caused by mechanisms of the vehicle. This paper reports simulation tests which were performed to determine the most effective method for correction of DRNS designed for a real Biomimetic AUV.
Źródło:
Polish Maritime Research; 2018, 1; 13-23
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A parametric method for preliminary determination of underwater vehicles deadweight
Autorzy:
Michalski, J. P.
Powiązania:
https://bibliotekanauki.pl/articles/258992.pdf
Data publikacji:
2012
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
designing of underwater vehicles
mass and deadweight of underwater vehicles
Opis:
This paper describes a method useful for determination of load carrying capacity of underwater vehicle, elaborated on the basis of investigations of series of vehicles of systematically changed geometrical dimensions. By using the set of the series of vehicles their structural mass and displacement – at a given structural material and assumed maximum permissible submersion depth – were determined, and next – approximation formulae for deadweight of vehicles were obtained. Vehicle’s form may be consisted of one or a few cylindrical floats of circular cross-section, ended with caps. The floats are joined together with a space pipe frame. Acceptability of design solutions results from comparison of working stress values in float’s shell plating with permissible stresses as well as critical stresses. The presented method may be useful in the preliminary stage of designing the underwater vehicles - i.e. may serve for preliminary determination of a vehicle deadweight – at its given, or determined, geometrical dimensions, maximum permissible submersion depth, as well as a selected structural material.
Źródło:
Polish Maritime Research; 2012, 2; 11-16
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ring thruster – a preliminary optimisation study of ferrofluid seal and propeller
Autorzy:
Szydło, Z.
Matuszewski, L.
Powiązania:
https://bibliotekanauki.pl/articles/963466.pdf
Data publikacji:
2007
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ferrofluid seals
underwater propulsion
Opis:
The article reports the course of preliminary examination of a ferrofluid seal applied in liquid environment. A newly built research rig is described, and results of pressure tests performed for different shaft rotations are discussed. Other studies carried out in the past only referred to the gas environment, while the present examination aims at finding an answer to the question whether magnetic liquids can be successfully used in underwater applications. The obtained answer is positive, but further, more comprehensive investigations of the problem are necessary.
Źródło:
Polish Maritime Research; 2007, S 1; 71-74
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Underwater wet repair welding of API 5L X65M pipeline steel
Autorzy:
Rogalski, G.
Fydrych, D.
Łabanowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/258860.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
underwater welding
wet welding
underwater pipeline
API 5L X65M steel
Opis:
This paper presents results of the research of effect of polymer insulation of pipeline made of API 5L X65M steel as well as underwater wet welding parameters on properties of joints made by covered electrodes. Effect of heat input on structure and hardness of joints during repair of underwater pipeline was analyzed. Welding defects like microcracks, micro-lacks of fusion, slag inclusions, as well as HAZ hardness increase over an assumed acceptance criterion for welded joints in pipes without anticorrosion polymer insulation, were identified. A significant effect of polimer insulation on structure and properties of welded joints, was found.
Źródło:
Polish Maritime Research; 2017, S 1; Bibliogr. 27 poz., rys., tab.
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The analysis of hydrodynamic forces and shape of towrope for an underwater vehicle
Autorzy:
Bielański, J.
Powiązania:
https://bibliotekanauki.pl/articles/258454.pdf
Data publikacji:
2007
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
underwater vehicle
towrope
calculating forces
Opis:
The paper presents a method of calculating forces in an underwater vehicle towrope as well as its shape under the influence of hydrodynamic forces induced by water flowing round the towrope and vehicle. The rope hydrodynamic loads are calculated from the Morison’s equation and the vehicle forces and moments by means of coefficients. An example of calculations for a vehicle has been performed in the Matlab system for one towing speed.
Źródło:
Polish Maritime Research; 2007, S 2; 83-94
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinematical control of motion of underwater vehicle in horizontal plane
Autorzy:
Garus, J.
Powiązania:
https://bibliotekanauki.pl/articles/259399.pdf
Data publikacji:
2004
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
underwater vehicle
autopilot
fuzzy logic
Opis:
In the paper presented is a method of designing a fuzzy-logic-based autopilot for control of horizontal motion of an unmanned underwater vehicle. The control system’s synthesis was performed under the assumption that the vehicle can move with variable linear and angular velocities and the quantities possible to be measured are: position and orientaŹtion of the vehicle in the inertial reference system. The task of the autopilot was to minimiŹze the mean squares of deviations from the motion trajectory given in the form of a broken line defined by the coordinates of successive turning points. To generate control signals three independent fuzzy PD controllers using the control principles based on the Mac Vicar-Whelan’s standard base, were applied. For the linguistic variables of each controller appropriate fuzzy sets were selected and linear membership functions of trapezoidal and triangular form were defined. The presented results of the simulation tests performed for the remotely operated underwater vehicle "Ukwiał", with and without influence of disturbances resulting from sea current, confirm the proposed approach to be correct and effective.
Źródło:
Polish Maritime Research; 2004, 2; 27-31
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametric method for determination of motion characteristics of underwater vehicles, applicable in preliminary designing
Autorzy:
Michalski, J. P.
Powiązania:
https://bibliotekanauki.pl/articles/258672.pdf
Data publikacji:
2009
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
underwater vehicles
preliminary designing method
Opis:
This paper describes a method for preliminary designing the autonomous underwater vehicles (AUV), especially useful in the case when requirements concerning kinematic and dynamic parameters of vehicle motion are given in design assumptions. Concept of the method is based on dynamic equations which describe vehicle planar motion in vertical and horizontal directions, resulting from action of screw propellers or water ballast, respectively. The motion equations were determined by applying simplifications concerning both geometrical description of vehicle’s form and flow phenomena. Their solutions were obtained in the form of closed analytical expressions which are both of cognitive and practical merits as they can serve to assess influence of vehicle’s design parameters on its motion characteristics and simultaneously are convenient to formulate design optimization problems. Application of the method was illustrated by the attached examples dealing with determination of kinematic and dynamic characteristics of motion of the vehicle „Scylla” of set geometrical configuration and propulsion parameters.
Źródło:
Polish Maritime Research; 2009, 2; 3-10
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance comparison of ToA and TDoA based tracking in underwater multipath environments using bernoulli filter
Autorzy:
Gunes, Ahmet
Powiązania:
https://bibliotekanauki.pl/articles/32917889.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
underwater target tracking
bernoulli filter
Time-of-Arrival
Time-Difference-of-Arrival
underwater multipath propagation
Opis:
Underwater localization and tracking is a challenging problem and Time-of-Arrival and Time-Difference-of-Arrival approaches are commonly used. However, the performance difference between these approaches is not well understood or analysed adequately. There are some analytical studies for terrestrial applications with the assumption that the signal arrival times are not correlated. However, this assumption is not valid for underwater propagation. To present the distinct nature of the problem under the water, a high-fidelity simulation is required. In this study, Time-of-Arrival and Time-Difference-of-Arrival approaches are compared using a ray tracing based propagation model. Moreover, basic methods to mitigate the multipath propagation problem are also implemented for Bernoulli filters. Since the Bernoulli filter is a joint detection and tracking filter, the detection performance is also analysed. Comparisons are done for all combinations of filter and measurement approaches. The results can help to design underwater localization systems better suited to the needs.
Źródło:
Polish Maritime Research; 2023, 1; 135-144
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of Tonal Underwater Noise Pattern from Cavitating Propellers with Special Attention to Ice Cover Effects
Autorzy:
Streckwall, H.
Bretschneider, H.
Powiązania:
https://bibliotekanauki.pl/articles/259712.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
cavitation
underwater noise
ice-covered areas
Opis:
To predict underwater noise spectra associated to regular occurrence of propeller cavitation we have extended an existing method [1] (used for the prediction of fluctuating hull pressures) to become applicable for effects that are linked to a finite speed of sound. In [2] an intermediate approach was realized where (besides the hull) far field boundaries were introduced but the incompressible flow assumption was kept. However compressibility effects become noticeable in the far field, which may be judged to start at some 2-3 propeller-diameters distance from the centre of the cavitation events, if we confine to emissions at 1st- 4th blade frequency. It was a logical continuation of our former efforts to realize a compressible flow model and integrate the propeller as a noise source. Having increased the functionality of our approach by referencing the speed of sound, the precision of the method was also somehow reduced. In our former approach, like in comparable approaches (see for instance [3] and [4]), the singularity system generating the near field propeller induced pressures involved various sources and vortices distributed on the propeller blades. With our current compressible approach this complexity was dropped, as a single point source substitutes the cavitating propeller. Such a simplification correlates with the assumption, that the monopole character of a noise source is decisive for the far field noise levels. In this contribution we outline the steps characterizing the procedure for predicting tonal underwater noise from cavitating propellers. In the first step a Vortex Lattice Method (VLM) is used to access the cavitation pattern on the propeller with special focus on the cavity volume attached to one blade. The second step accumulates the distributed cavities to establish a fluctuating point source of equivalent far field noise characteristic. As relevant limits the hull, the free surface, the sea bottom and an ice cover are introduced. Using finally a Boundary Element Method (BEM) approach the relevant noise characteristics are derived, accounting for external boundaries and for the finite speed of sound. The results provided here are focused on a comparative treatment of different scenarios, mainly addressing ice cover effects at finite the water depth.
Źródło:
Polish Maritime Research; 2014, 4; 35-40
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of effectiveness of waterjet propulsor for a small underwater vehicle
Autorzy:
Rowinski, Lech
Kaczmarczyk, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/2033211.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship propulsion
hydromechanics
waterjet
underwater vehicle
Opis:
The goal of the project described is to replace the existing propulsion system of a small underwater vehicle with a solution less prone to mechanical damage and ensuring a lower risk of the entanglement of fibrous objects suspended in the body of water. Four typical marine screws are utilised in the current design of the vehicle. One possible solution of the problem is the application of waterjet propulsors located inside the body of the vehicle instead. The general conditio of the application of the new solution was to secure at least the same motion control capabilities of the vehicle while the basic capability is its propulsion effectiveness at the required speed. Specific features of the considered waterjet propulsor, when compared with their application in surface vessel propulsion, are the lack of the head losses and the low significance of cavitation issues. One of the difficulties in the considered case is the small diameter of the propulsor in comparison to commercially available waterjet units, which have diameters between 0.1 [m] and 1.0 [m]. There is very little data regarding the design and performance of devices in the 0.02 to 0.05 [m] range. Methods utilised to forecast the performance of the new propulsion system are presented and results compared. These were semi-empirical calculations, numerical calculations and tests of real devices. The algorithm that is based on semi-empirical calculations is of particular interest while it offers possibility quick assessment of performance of a propulsor composed of several well defined components. The results indicate the feasibility of modification of the propulsion system for the considered vehicle if all the existing circumstances are taken into account.
Źródło:
Polish Maritime Research; 2021, 4; 30-41
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical study of the effect of wing position on the dynamic motion characteristics of an underwater glider
Autorzy:
Wu, Xiangcheng
Yu, Pengyao
Li, Guangzhao
Li, Fengkun
Powiązania:
https://bibliotekanauki.pl/articles/1551828.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
underwater glider
motion simulation
wing position
Opis:
Underwater gliders are winged, autonomous underwater vehicles that are broadly applied in physical and biological oceanography. The position of the wing has an important effect on the movement performance of the underwater glider. In this paper, the dynamic motion of a series of underwater glider models with different longitudinal wing positions are simulated, which provides guidance for the design of underwater gliders. The results show that when the net buoyancy is constant, the wing position affects the gliding angle, but does not affect the relationship between the gliding angle and the gliding speed. In addition, the farther the wing position of the glider is from the buoyancy centre, the longer it takes for the attitude of a glider to change, whether the wing is in front of, or behind, the buoyancy centre.
Źródło:
Polish Maritime Research; 2021, 2; 4-17
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Classification of the underwater diving equipment
Autorzy:
Kłos, R.
Powiązania:
https://bibliotekanauki.pl/articles/258550.pdf
Data publikacji:
2008
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
diving apparatus
classification
underwater diving equipment
Opis:
In this paper was presented, innovative in preparation of the diving apparatuses classification method, depend on three criteria: the kind of the breathing gas, the operational depth range of the diving apparatus, and the principle of operation. The breathing gas used is the most important criterion. The other basic classification criteria follow from the first one; therefore it should be treated as the one criterion. Such approach to the problem has never been presented before, however it seems to be correct method of the diving apparatuses division.
Źródło:
Polish Maritime Research; 2008, 1; 80-85
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Underwater navigation system based on Doppler shift – measurements and error estimations
Autorzy:
Ostrowski, Zawisza
Salamon, Roman
Kochańska, Iwona
Marszal, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/260234.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
underwater acoustics
navigation systems
Doppler shifts
Opis:
A new acoustic navigation system was developed to determine the position and speed of moving underwater objects such as divers and underwater vehicles. The path of an object and its speed were determined by the Doppler shifts of acoustic signals emitted by a transmitter placed on the object and received by four hydrophones installed at the periphery of the monitored body of water. The position and speed measurements were affected by errors mainly caused by acoustic reflections (returns) from the water body boundaries and surface reverberations. This paper discusses the source of the disturbances with the results of a simulation test and experimental measurements. It was demonstrated that the magnitude of the errors could be acceptable in most of the potential applications of the acoustic navigation system.
Źródło:
Polish Maritime Research; 2020, 1; 180-187
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Use of UIOT for offshore surveys through autonomous vehicles
Autorzy:
Sanchez, Pedro Jose Bernalte
Márquez, Fausto Pedro García
Govindara, Shashank
But, Alexandru
Sportich, Benjamin
Marini, Simone
Jantara, Valter Junior
Papaelias, Mayorkinos
Powiązania:
https://bibliotekanauki.pl/articles/1955604.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
Underwater Internet of Things (UIoT)
autonomous underwater vehicles
unmanned surface vehicles
clean energy
data management
data transmission
Opis:
The ENDURUNS project is a European Research project of the Horizon 2020 framework, which has as its main objective to achieve the optimum and intelligent use of green hydrogen energy for long-term ocean surveys. The ENDURUNS system comprises an Unmanned Surface Vehicle (USV) and an Autonomous Underwater Vehicle (AUV) with gliding capability. The power pack of the USV integrates Li-ion batteries with photovoltaic panels, whilst the AUV employs Li-ion batteries and a hydrogen fuel cell. It is essential to develop a continuous monitoring ca-pability for the different systems of the vehicles. Data transmission between the devices onboard presents challenges due to the volume and structure of the different datasets. A telecommunications network has been designed to manage the operational components considered in the project. The autonomous vehicles perform measurements, providing their position and other data wirelessly. The system will generate a great volume of various signals during the survey. The Remote Control Centre needs to be interfaced with the vehicles in order to receive, manage and store the acquired data. An Underwater Internet of Things (IoT) platform is designed to establish efficient and smart data management. This study presents an exhaustive survey to analyse the telecommunication systems employed in the autonomous vehicles, including the back-end, user interface and mobile units. This paper presents the novel design of the hardware and software structure of the ENDURUNS project with regard to the literature, where its components and their in-terconnection layers are detailed, which is a novel scientific and technological approach for autonomous seabed surveying in deep oceans or in coastal areas.
Źródło:
Polish Maritime Research; 2021, 3; 175-189
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Visual identification of underwater objects using a ROV-type vehicle: “Graf Zeppelin” wreck investigation
Autorzy:
Olejnik, A.
Powiązania:
https://bibliotekanauki.pl/articles/258548.pdf
Data publikacji:
2008
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
wreck Graf Zeppelin
visual identification underwater objects
Opis:
The article presents a method of visual identification of underwater objects using a remotely controlled underwater ROV-type vehicle. The method was developed in the Department of Diving Technology and Underwater Activities, Polish Naval Academy, and was positively verified when identifying wrecks of such vessels as “General von Steuben”, “Fryderyk Engels” and “Graf Zeppelin”. The article gives a description of the method, illustrated by samples of its use for investigating the wreck of “Graf Zeppelin”.
Źródło:
Polish Maritime Research; 2008, 1; 72-79
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 39

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