AUV/ASC cooperative survey

In this paper we describe a solution to perform autonomous surveys taking advantage of a cooperative multivehicle setup. In the proposed configuration, an ASC provides –through an USBL- absolute positioning and communications to an AUV. Thus, by following the AUV with the surface vehicle we facilitate the reception of USBL measurements in the AUV regardless of the extent of the mission. This turns into an improved navigation on the AUV’s side, with the drift bounded thanks to the absolute measurements. Experimental results show that the proposed algorithm is able to maintain the ASC at a close distance and improve the navigation of the AUV. Moreover, the bathymetric maps built from the AUV data are consistent enough to enable the automatic detection of present targets and program further localized missions in the area.Peer Reviewe

Active SLAM for autonomous underwater exploration

Exploration of a complex underwater environment without an a priori map is beyond the state of the art for autonomous underwater vehicles (AUVs). Despite several efforts regarding simultaneous localization and mapping (SLAM) and view planning, there is no exploration framework, tailored to underwater vehicles, that faces exploration combining mapping, active localization, and view planning in a unified way. We propose an exploration framework, based on an active SLAM strategy, that combines three main elements: a view planner, an iterative closest point algorithm (ICP)-based pose-graph SLAM algorithm, and an action selection mechanism that makes use of the joint map and state entropy reduction. To demonstrate the benefits of the active SLAM strategy, several tests were conducted with the Girona 500 AUV, both in simulation and in the real world. The article shows how the proposed framework makes it possible to plan exploratory trajectories that keep the vehicle’s uncertainty bounded; thus, creating more consistent maps.Peer ReviewedPostprint (published version

Shared autonomy for mapping and exploration of underwater environments using an HROV

One of the main goals in robotics is to achieve full autonomy. However, for certain tasks, robots still lack the level of abstract reasoning that gives the ability to make decisions, plan ahead, and change actions during the execution of a process, these abilities are acquired at its best degree only by humans. In terms of unknown underwater environments, the combination of specialized robotics that can withstand harsh environments and the reasoning of a human operator can give effective results on exploration, inspection, and subsequent tasks. Standard solutions propose to use fully teleoperated Remotely Operated Vehicles (ROV)s or fully Autonomous Underwater Vehicles (AUV). Still, both solutions have their drawbacks: high operation costs and limitations due to the need of a physical connection in the case of ROVs, and limitations in the communications or problems while facing complex decision making in case of AUVs. These limitations can be overcome with the concept of shared autonomy applied to a Hybrid ROV (HROV). In this new paradigm, an operator leads the mission by selecting objectives at a high level, and a HROV executes them taking all the low level decisions. This paper explores the shared autonomy concept applied to an underwater exploration task, leading the first steps towards intervention missions.Peer Reviewe

Coverage Path Planning with Real‐time Replanning and Surface Reconstruction for Inspection of Three‐dimensional Underwater Structures using Autonomous Underwater Vehicles

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113717/1/rob21554.pd

Seabed monitoring with Girona 500 AUV working as HROV

This paper presents the use of Girona 500 AUV as a Hybrid ROV (HROV) to inspect underwater habitats by combining basic teleoperation and automatic way-point following. This duality allows safe movements, when inspecting visually the seabed, together with precise way-point movements, when mapping or reaching the area. Also, the use of a HROV containing its own energy simplifies the management of the umbilical cable, which can be smaller, and integrates all safety measures of an AUV. The Girona 500 AUV has been tested acting as HROV during 3 campaigns at 80 metres depth in a project for evaluating the state of transplanted gorgonians.Peer Reviewe

Two-dimensional frontier-based viewpoint generation for exploring and mapping underwater environments

To autonomously explore complex underwater environments, it is convenient to develop motion planning strategies that do not depend on prior information. In this publication, we present a robotic exploration algorithm for autonomous underwater vehicles (AUVs) that is able to guide the robot so that it explores an unknown 2-dimensional (2D) environment. The algorithm is built upon view planning (VP) and frontier-based (FB) strategies. Traditional robotic exploration algorithms seek full coverage of the scene with data from only one sensor. If data coverage is required for multiple sensors, multiple exploration missions are required. Our approach has been designed to sense the environment achieving full coverage with data from two sensors in a single exploration mission: occupancy data from the profiling sonar, from which the shape of the environment is perceived, and optical data from the camera, to capture the details of the environment. This saves time and mission costs. The algorithm has been designed to be computationally efficient, so that it can run online in the AUV’s onboard computer. In our approach, the environment is represented using a labeled quadtree occupancy map which, at the same time, is used to generate the viewpoints that guide the exploration. We have tested the algorithm in different environments through numerous experiments, which include sea operations using the Sparus II AUV and its sensor suite

Industrial dynamics, innovation and the urban system in Spain: trajectories of medium-sized cities

[ES] El artículo pretende un primer acercamiento a las dinámicas industriales de las ciudades intermedias españolas. Además de una revisión de las teorías económicas convencionales del crecimiento industrial localizado, en la explicación se incide en claves internas y específicas para cada ciudad, como la posible existencia de sistemas productivos capaces de activar círculos virtuosos de innovación. Para ello se analizan la evolución y estructura sectorial dentro del sistema urbano español, a partir de los datos de empresas y empleo de la Seguridad Social (2000-2006), explorando la asociación espacial de ambos aspectos con diversos indicadores de innovación económico-empresarial.[EN] The article endeavours to provide an approach to the industrial dynamics of mediumsized Spanish cities. In addition to containing a survey of the conventional economic theories on localised industrial growth, the explanation stresses internal keys specific to each city, such as the possible existence of production systems that can activate virtuous circles of innovation. Evolution and sector structure within the Spanish urban system are therefore analysed, on the basis of business and employment figures from Social Security (2000-2006), exploring the spatial association of both aspects with diverse indicators of economic and business innovation.El artículo forma parte del proyecto de investigación sobre Estrategias de innovación industrial y desarrollo económico en las ciudades intermedias de España, financiado por la Fundación BBVA (2006-2008).Peer reviewe

Sparus II AUV - a hovering vehicle for seabed inspection

This paper proposes the use of path-planning algorithms for hovering autonomous underwater vehicles (AUVs) in applications where the robot needs to adapt online its trajectory for inspection or safety purposes. In particular, it proposes the platform Sparus II AUV and a set of planning algorithms to conduct these new AUV capabilities. These algorithms generate trajectories under motion constraints, which can be followed without deviations, to ensure the safety even when passing close to obstacles. View planning algorithms are also combined to decide the movements to be executed to discover the unexplored seabed or target, and to cover it with a camera or sonar. Online mapping with profiling sonars and online planning with fast sampling-based algorithms allow the execution of missions without any previous knowledge of the 3-D shape of the environment. Real 2-D results in an artificial harbor structure and simulated natural rocky canyon demonstrate the feasibility of the approach for avoiding or inspecting the underwater environment. These new AUV capabilities can be used to acquire images of the environment that can be used to inspect and map the habitat

I-AUV Docking and Panel Intervention at Sea

The use of commercially available autonomous underwater vehicles (AUVs) has increased during the last fifteen years. While they are mainly used for routine survey missions, there is a set of applications that nowadays can be only addressed by manned submersibles or work-class remotely operated vehicles (ROVs) equipped with teleoperated arms: the intervention applications. To allow these heavy vehicles controlled by human operators to perform intervention tasks, underwater structures like observatory facilities, subsea panels or oil-well Christmas trees have been adapted, making them more robust and easier to operate. The TRITON Spanish founded project proposes the use of a light-weight intervention AUV (I-AUV) to carry out intervention applications simplifying the adaptation of these underwater structures and drastically reducing the operational cost. To prove this concept, the Girona 500 I-AUV is used to autonomously dock into an adapted subsea panel and once docked perform an intervention composed of turning a valve and plugging in/unplugging a connector. The techniques used for the autonomous docking and manipulation as well as the design of an adapted subsea panel with a funnel-based docking system are presented in this article together with the results achieved in a water tank and at sea.This work was supported by the Spanish project DPI2014-57746-C3 (MERBOTS Project) and by Generalitat Valenciana under Grant GVA-PROMETEO/2016/066. The University of Girona wants to thank the SARTI group for their collaboration with the TRITON project

I-AUV Docking and Panel Intervention at Sea

The use of commercially available autonomous underwater vehicles (AUVs) has increased during the last fifteen years. While they are mainly used for routine survey missions, there is a set of applications that nowadays can be only addressed by manned submersibles or work-class remotely operated vehicles (ROVs) equipped with teleoperated arms: the intervention applications. To allow these heavy vehicles controlled by human operators to perform intervention tasks, underwater structures like observatory facilities, subsea panels or oil-well Christmas trees have been adapted, making them more robust and easier to operate. The TRITON Spanish founded project proposes the use of a light-weight intervention AUV (I-AUV) to carry out intervention applications simplifying the adaptation of these underwater structures and drastically reducing the operational cost. To prove this concept, the Girona 500 I-AUV is used to autonomously dock into an adapted subsea panel and once docked perform an intervention composed of turning a valve and plugging in/unplugging a connector. The techniques used for the autonomous docking and manipulation as well as the design of an adapted subsea panel with a funnel-based docking system are presented in this article together with the results achieved in a water tank and at sea.This work was supported by the Spanish project DPI2014-57746-C3 (MERBOTS Project) and by Generalitat Valenciana under Grant GVA-PROMETEO/2016/066. The University of Girona wants to thank the SARTI group for their collaboration with the TRITON project