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Publications

Publications by CRAS

2016

Towards LBL Positioning Systems for Multiple Vehicles

Authors
Melo, J; Matos, A;

Publication
OCEANS 2016 - SHANGHAI

Abstract
In this article we discuss the use of LBL acoustic networks for operations with multiple AUVs. Differently from standard LBL configurations, we propose to use the One-Way-Travel-Time of acoustic signals to compute the ranges between all the devices. Moreover, we derive the suitable algorithms for both the navigation of multiple vehicles, but also their external tracking. Experimental results are provided that support the evidence that our approach is successful in operations for multiple vehicles.

2016

Optimal Control Problems for Path Planing of AUV using Simplified Models

Authors
de Pinho, MD; Foroozandeh, Z; Matos, A;

Publication
2016 IEEE 55TH CONFERENCE ON DECISION AND CONTROL (CDC)

Abstract
Here we propose a simplified model for the path planning of an Autonomous Underwater Vehicle (AUV) in an horizontal plane when ocean currents are considered. The model includes kinematic equations and a simple dynamic equation. Our problem of interest is a minimum time problem with state constraints where the control appears linearly. This problem is solved numerically using the direct method. We extract various tests from the Maximum Principle that are then used to validate the numerical solution. In contrast to many other literature we apply the Maximum Principle as defined in [9].

2016

A Mosaicking Approach for Visual Mapping of Large-Scale Environments

Authors
Pinto, AM; Pinto, H; Matos, AC;

Publication
2016 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS (ICARSC 2016)

Abstract
Nowadays, the technological and scientific research related to underwater perception is focused in developing more cost-effective tools to support activities related with the inspection, search and rescue of wreckages and site exploration: devices with higher autonomy, endurance and capabilities. Currently, specific tasks are already carried out by remotely-operated vehicles (ROV) and autonomous underwater vehicles (AUV) that can be equipped with multiple sensors, including optical cameras which are extremely valuable for perceiving marine environments; however, the current perceptual capability of these vehicles is still limited. In this context, the paper presents a novel mosaicking method that composes the sea-floor from a set of visual observations. This method is called RObust and Large-scale MOSaicking (ROLAMOS) and it enables an efficient frame-to-frame motion estimation with outliers removal and consistence checking, a robust registration of monocular images and, finally, a mosaic management methodology that makes it possible to map large visual areas with a high resolution. The experiments conducted with realistic images have proven that the ROLAMOS is suitable for mapping large-scale sea-floor scenarios because the visual information is registered by managing the computational resources that are available onboard, which makes it appropriate for applications that do not have specialized computers. Further, this is a major advantage for automatic mosaic creation based on robotic applications, that require the location of objects or even structures with high detail and precision.

2016

Air and Underwater Survey of water enclosed spaces for VAMOS! Project

Authors
Almeida, J; Ferreira, A; Matias, B; Dias, A; Martins, A; Silva, F; Oliveira, J; Sousa, P; Moreira, M; Miranda, T; Almeida, C; Silva, E;

Publication
OCEANS 2016 MTS/IEEE MONTEREY

Abstract
This paper addresses a three-dimensional (3D) reconstruction of a flooded open pit mine with an autonomous surface vehicle (ASV) and unmanned aerial vehicle (UAV). The ROAZ USV and the Otus UAV were used to provide the underwater bathymetric map and aerial 3D reconstruction based from image data. This work was performed wihtin the context of the European researcj project VAMOS with the objective of developing robotic tools for efficient underwater mining

2016

ISEP/INESC TEC Aerial Robotics Team for Search and Rescue Operations at the EuRathlon Challenge 2015

Authors
Sousa, P; Ferreira, A; Moreira, M; Santos, T; Martins, A; Dias, A; Almeida, J; Silva, E;

Publication
2016 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS (ICARSC 2016)

Abstract
This paper presents the autononomous aerial vehicle OTUS and its application to search and rescue scenarios, namely the participation on the EuRathlon 2015 competition. The OTUS robot was developed at INESC TEC/ ISEP for research in cooperative aerial robotics and applications in complex and dynamic environments. The system was validated in this challenging scenario and was able to win the Grand Challenge scenario in cooperation with a land and marine robotics partner teams.

2016

MarinEye - A tool for marine monitoring

Authors
Martins, A; Dias, A; Silva, E; Ferreira, H; Dias, I; Almeida, JM; Torgo, L; Goncalves, M; Guedes, M; Dias, N; Jorge, P; Mucha, AP; Magalhaes, C; Carvalho, MDF; Ribeiro, H; Almeida, CMR; Azevedo, I; Ramos, S; Borges, T; Leandro, SM; Maranhao, P; Mouga, T; Gamboa, R; Lemos, M; dos Santos, A; Silva, A; Teixeira, BFE; Bartilotti, C; Marques, R; Cotrim, S;

Publication
OCEANS 2016 - SHANGHAI

Abstract
This work presents an autonomous system for marine integrated physical-chemical and biological monitoring - the MarinEye system. It comprises a set of sensors providing diverse and relevant information for oceanic environment characterization and marine biology studies. It is constituted by a physical-chemical water properties sensor suite, a water filtration and sampling system for DNA collection, a plankton imaging system and biomass assessment acoustic system. The MarinEye system has onboard computational and logging capabilities allowing it either for autonomous operation or for integration in other marine observing systems (such as Observatories or robotic vehicles. It was designed in order to collect integrated multi-trophic monitoring data. The validation in operational environment on 3 marine observatories: RAIA, BerlengasWatch and Cascais on the coast of Portugal is also discussed.

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