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This paper presents a novel underwater movement compensation algorithm for stabilization of manipulator position utilizing not ROV movements for disturbance compensation, but overlaid manipulator movements. A model based estimator is used to predict vehicle movement and provide the manipulation system with the necessary time to compensate for the estimated motion. It describes the conceptual benefits...
In this paper we describe a hardware facility to simulate movements of a remotely operated underwater vehicle (ROV) in a water basin for the evaluation of novel underwater manipulation techniques as it was build at the underwater robotics department of the German Research Center for Artificial Intelligence (DFKI) in Bremen. The three main functionalities of the ROV simulator are to drive predefined...
Maritime surveillance and monitoring are tasks suitable for autonomous marine vessels. In order to obtain accurate path following of these vessels, environmental disturbances need to be taken into account. For the case of constant disturbances, control strategies such as integral action, sliding mode control and adaptive control can be employed, each with their own benefits and drawbacks. Here we...
In this short note we give an overview on the development of a new versatile plankton video recording system named LOKI. In addition to the introduction of technical specifications and background information of the device we also demonstrate a possible scientific application in a case study performed in an upwelling area off the Namibian coast.
A terrain aided navigation correction system has been developed for use with the autonomous underwater vehicle (AUV) Autosub 6000. This system allows drift in dead-reckoning navigation to be estimated by matching bathymetry observed in multibeam echosounder (MBE) data to a reference map. The reference map consists of a single line of bathymetric data, one swath width across, spanning the operational...
Swarms of underwater autonomous vehicles (UAVs) are being increasingly used in civilian and military applications. Formations of UAVs are being utilized to detect mine-like objects and oilfields, collect water quality information, detect intruders, and in navigation assistance applications, among others. This paper introduces a new data link layer for underwater communications suitable for non-synchronized...
The utility and cost-effectiveness of instrument networks are enhanced by instrument interoperability. Today's oceanographic instruments are characterized by very diverse non-standard software protocols and data formats. This diversity of protocols poses serious challenges to integration of large-scale sensor networks. Standard instrument protocols are now being developed to address these challenges...
Sound emitted by a turboprop aircraft in level flight is received by each of the uniformly spaced hydrophones of a horizontal line array located below the sea surface. The primary signal emitted by the source is an acoustic tone corresponding to the propeller blade rate of the aircraft. As the airborne source is in relative motion with respect to the array, the received signal at each hydrophone is...
Current maritime systems are to a large extent based on legacy analog VHF radios for ship-to-shore communications near port waters, and relatively low bandwidth digital satellite communications (SatCom) for long-range ship-to-ship and ship-to-shore communications. The cost of bandwidth for SatCom networks is expected to remain high due to the cost of launching satellites into orbit and also due to...
The work we present is an analytical method to estimate the tidal current induced bottom shear stress. The method is based on radar remote sensing measurements and in situ data. The results of the method are irrotational maps of the bottom shear stress and the initiation of motion.
In this paper, we present a new small autonomous underwater vehicle (AUV) called Taipan 300. First, we detail its technical features. Then, we explain how the particular hardware design of this vehicle makes its recovery easier in case of software or hardware failure. In fact this prototype offers enhanced safety measures in order to detect computer failure and to facilitate vehicle localization after...
The selection of an external pressure vessel material is described. Failures in the rupture and buckle modes are discussed, as well as the problem of submarine hull hydrostatics. A spherical geometry admits simplification to allow focus on the economic problem. The economic cost function is comprised of 28 variables: the market prices of the alloy components, some material properties of the alloy,...
International Maritime Organization adopted the International Convention for the Control and Management of Ships' Ballast Water and Sediments in 2004 to prevent the transfer of aquatic organisms through ballast water. The Convention is expected to be applied in 2010. About 30 ballast water treatment systems are developing now in the world using the technologies of mechanical separation, micro-agitation,...
For all Ocean related activities it is necessary to predict the actual water levels as accurate as possible. The present work aims at predicting the water levels with a lead time of few hours to a day using the technique of artificial neural networks. Instead of using the previous and current values of observed water level time series directly as input and output the water level anomaly (difference...
Thraustochytrids are considered highly oleaginous marine microorganisms with excellent polyunsaturated fattys (PUFAs) and also with high carotenoid content. It is considered good microorganism as human dietary additive and feed-enrichment alternative. The present study was aimed at analyzing any changes in percentage of fatty acids and carotenoid content by subjecting a culture of Thraustochytrid...
Cooperative robotics have been one of the hot topics of research for different scientific and technological fields throughout the last decade. Extending the concepts explored in land and aerial robotics to the underwater application scenarios have proven to be particularly difficult due to the limitations of the available communication channels, lack of standardization, etc. The GREX project aims...
Remote sensing data have been widely used in environmental studies like land cover change, flood observation, environmental pollution monitoring. The turbidity is commonly measured by turbidity meter. However, it is only accurate for single point measurement but ineffective for wide spatial and temporal coverage. The launching of Earth Observation Satellites (EOS) of ALOS by carrying high spectral...
During the past 10 years, large developments and improvements on the technical possibilities and operational availability of full size, Class III deep ocean work ROVs took place (> 3000 m). This is especially true for the marine science community. Where in the early 90's scientific ROVs for ultradeep operations were a true technical challenge for technology leading institutions like IFREMER, MBARI,...
The development of an integrated coastal observing system for the German Bight and Arctic Coastal Seas (COSYNA) is one of the focal issues of German marine research in the next decade. A major challenge of COSYNA is to tightly merge data from a dense observational network and modeling via data assimilation. The integrated system will focus on daily-to-weekly processes providing objective measures...
The topic of this paper is to describe design options for a hammering drill (`mole') device for the deep sea environment. Such a system was originally developed by the German Aerospace Center DLR for a mission to Mars aboard the BEAGLE 2 lander of the European Space Agency's (ESA) MARS EXPRESS mission, which was lost during landing on the planet in December 2003. Now a second generation mole system...
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