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A navigation strategy for achieving quasi-optimality for autonomous underwater vehicles (AUVs) is presented. The objective of the optimal navigation is the minimum-time transit of an AUV in a flow field of sea current disturbance. Reactive optimal guidance revisions followed by tracking controls are the key features of the proposed quasi-optimal navigation strategy. In this research, a globally working...
This paper presents a novel approach to the design of globally asymptotically stable (GAS) position filters for Autonomous Underwater Vehicles (AUVs) based directly on the nonlinear sensor readings of an Ultra-short Baseline (USBL) and a Doppler Velocity Log (DVL). Central to the proposed solution is the derivation of a linear time-varying (LTV) system that fully captures the dynamics of the nonlinear...
In recent years, adaptive and autonomous exploration of underwater plumes with autonomous underwater vehicles (AUVs) becomes a hot research topic, due to its significant applications. For the researches on AUV underwater plume exploring, design, optimization and validation of the control strategies and autonomous behaviors of the AUVs is the key issue. In order to study various control strategies...
Autonomous Underwater Vehicles are a leading technology for under-ice deployment and research. Memorial University and its Explorer AUV, in cooperation with the University of Tasmania and the Australian Antarctic Division, has embarked on a multi-phase development program that will lead to a scientific mission in the Australian Antarctic. Completion of Phase I saw the AUV deployed in the Canadian...
The thermocline is a vertical transition layer in the water column with a strong impact on marine biology, since it affects phytoplankton concentration and, hence, primary production. AUVs can play an important role in understanding this relationship, by sampling the relevant data, usually describing yo-yo patterns spanning the whole water column. In this paper we describe a reactive behavior implemented...
Due to its significant potential applications, underwater chemical plume exploration and source localization via an autonomous underwater vehicle (AUV) is currently a hot subject both in AUV and oceanic engineering research communities. Chemical plume including buoyant stem and non-buoyant part such as deep-sea hydrothermal plume is a typical dynamic 3D feature in the ocean environment; therefore,...
As autonomous underwater vehicles universally establish themselves as invaluable tools to provide unprecedented results in a variety of scientific, industrial and naval scenarios, the focus of development is gradually shifting towards considering the operation of multiple cooperating vehicles. There is widespread consensus on that despite the added complexity of having to operate several vehicles,...
This paper reports an overview of the new Nereus hybrid underwater vehicle and summarizes the vehicle's performance during its first sea trials in November 2007. Nereus is a novel operational underwater vehicle designed to perform scientific survey and sampling to the full depth of the ocean of 11,000 meters - almost twice the depth of any present-day operational vehicle. Nereus operates in two different...
This paper focuses on the positioning control of of a small size autonomous surface vessel (ASV) that can be used to carry a multitude of payload systems, including acoustic devices for underwater positioning and for communications with autonomous underwater vehicles. Its main motivation is the development of highly operational systems, by replacing typically moored support infrastructures with others...
Optimal and quasi-optimal navigations of an AUV achieved by the minimum time guidance in undersea area of sea currents are presented. When an AUV is to transfer to a given destination within an area of sea current disturbance, ingenious guidance enables the minimization of navigation time. In this study, a numerical procedure to obtain solution of the optimal guidance law in undersea area of sea current...
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