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Study of innovative autonomous marine vehicles for monitoring in remote areas and shallow waters The Shallow Water Autonomous Multipurpose Platform (SWAMP)
No full textThe main objective of the research activity covered by the present thesis is the design of an
Autonomous Surface Vehicle for the monitoring of environmental areas characterised by shallow
water, difficult access and harsh environment, namely the Wetlands.
Wetlands are those geographic areas where water meets the earth that cover between 5 and 8%
of the Earth’s surface. Wetlands include mangrove zones, swamps, bogs and marshes, rivers and
lakes, alluvial plains and flooded forests, shallow coasts and coral reefs. In recent years, their importance
is becoming more and more recognized and various international conventions, directives and
projects work on their protection. Their importance is related to the fact that these areas are essential
ecosystems considered among the world’s most productive environment. Classified as natural
purification systems and carbon resources for fauna, Wetlands provide the water and productivity
upon which biological diversity relies for the growth of an enormous amount of species of plants
and animals. Their importance is also related to human activities since Wetlands can be exploited
commercially for fishing but especially become important when thinking that the protection of these
areas can also help fighting the disasters resulting from human impact on the environment and its
role in the climate change.
The lack of a hydro-graphic vessels capable of performing shallow water measurements at depths of
less than 1m has led to unreliable maps and data, thus motivating research on innovative technical
approaches for executing the tasks of water sampling, limnological surveys, bathymetric analyses
and monitoring of water quality. In recent years a variety of robotic approaches to improve the
quality, speed, and accessibility of surveys have been explored by research groups using both commercial
and ad-hoc solutions.
In this thesis a prototype of Autonomous Surface Vehicle (ASV) named SWAMP (Shallow Water
Autonomous Multipurpose Platform) is proposed as the base for an innovative class of reliable modular
re-configurable lightweight ASVs for extremely shallow water applications. The vehicle was
studied to solve the problem of monitoring the water status in the Wetlands but the SWAMP class
ASV will also be able to support, as test-bed, the research on many aspects of marine engineering
and robotics like propulsion issues, structure issues, artificial intelligence, cooperative distributed
control, Guidance, Navigation and Control (GNC) systems as well as innovative technological solutions
in terms of communication, materials, sensors and actuators.
The heterogeneity of the themes treated by this thesis relies on the fact that the whole aspects of
design were taken into consideration.
In this thesis the description of the design, modeling, construction and testing of the new concept
of Autonomous Surface Vehicles (ASV) is illustrated. The motivations behind the necessity of a
new system are described in Chapter 1 and 2 while in Chapter 3 the general considerations on the
requirements that led to the definition of the specifications of a special layout are reported.
In Chapter 4 the design of the vehicle layout is illustrated together with the description of an innovative
soft-material hull structure on which extensive analyses in towing tank were performed. The
tests were carried out both in deep and shallow water to completely identify the surge motion of
the ASV.
The hardware, software and mechanical modularity represent some main ideas behind the conception
of SWAMP. The two hulls of SWAMP are two separate modules. Each hull can be composed
of more or less structural elements, actuation modules, powering elements, control units, sensors.
This can be done without constraints thanks to the novel communication architecture all based on
Wi-Fi modules.
In Chapter 5 the thrusters expressly studied for environmental monitoring in the extremely shallow
waters of the Wetlands (rivers, lakes swamps, marshes, mangroves..) are illustrated. These systems
were modeled, designed and constructed on the Pump-Jet concept. Four Pump-Jet Module s for a
class of small/medium size ASV were built and the description of the design and tests are reported
in the thesis. The extremely modular hardware control system of SWAMP is described in Chapter 6
where also the modules composing the vehicle are described. Once assembled, the vehicle was tested
at sea in various environments. A series of pioneering tests with the application of Machine Learning
and the citizen’s engagement in teaching to a robot to self-control are described in the Chapter 7,
together with more standard results. The algorithm for the training of a neural network for the
control of SWAMP was tested also by using the simulator described in Chapter 8.
The conclusions of this work, reported in Chapter 9, are correlated with a visionary analysis of the
possible applications of SWAMP in a series of futuristic research trends of marine robotics
Unmanned Marine Vehicles
No full textWater covers nearly 70% of the Earth’s surface, and throughout history, oceans, seas, lakes, rivers, etc [...
River Survey Evolution by means of Autonomous Surface Vehicles
No full textLiguria (Italy) is one of the European regions where extreme events related to anthropogenic changes have had the greatest number of negative effects. In this area the use of suitable robots can improve monitoring the impact of anthropogenic pressure in wetland ecosystems. A recent bathymetry survey took place with an ASV named SWAMP that was specifically designed for the extremely shallow waters peculiar of rivers and inland waters. SWAMP was equipped with a single beam sonar protected inside the hull and performed a bathimetry in the area where Roja river flows not far from the Italy-France border. During the survey SWAMP proved to be easily transportable in a harsh environment and to be capable of working in extremely shallow water without any risk for sensors and propulsion and to be highly manoeuvrable in narrow space
Design and construction of a modular pump-jet thruster for autonomous surface vehicle operations in extremely shallow water
No full textThis paper describes a customized thruster for Autonomous Surface Vehicles (ASV). The thruster is a Pump-Jet Module (PJM), which has been expressly designed, modeled, constructed, and tested for small-/medium-sized ASVs that perform environmental monitoring in extremely shallow waters such as wetlands (rivers, lakes, swamps, marshes), where water depth is only a few centimeters. The PJM is a fully-electric propulsion unit with a 360-degree continuous steering capability. Its main advantage is that the unit is flush with the flat bottom of the vehicle. This makes the PJM suitable for operation in extremely shallow waters because the risk of damaging the thrusting unit in case of grounding is very limited. The PJM was produced using innovative materials, and the hydraulic components were all constructed using a 3D printer
A preliminary experiment combining marine robotics and citizenship engagement using imitation learning
No full textIn this paper, we describe a preliminary experiment of citizenship engagement in the context of marine robotics using imitation learning to train a controller that mimics human behavior. The experiment has been carried out during the Festival della Comunicazione in Camogli, Italy, in September 2019. In more detail, citizens have been asked to pilot a small, light, and safe autonomous surface vehicle in front of a crowded public beach with the goal of performing an S-shaped path. The trajectories and controls performed by non-expert human operators have been recorded with the aim of training an imitation system that, after collecting a sufficient number of trajectory-control pairs, has been able to drive the vehicle without human intervention. To learn the human behavior, echo state networks have been employed as approximating architectures. The resulting controller turned out to be very effective in successfully performing the considered experiment with a reduced amount of training trajectories by imitating the human behavior also in unknown situations. The success of this experiment may pave the way to new research processes where citizens are actively engaged. Copyright (C) 2020 The Authors
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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