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Publications

Publications by Alfredo Martins

2019

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

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

Publication
JOURNAL OF INTELLIGENT & ROBOTIC SYSTEMS

Abstract
This paper presents the results from search and rescue missions performed with the aerial robot OTUS in the the context of the ISEP/INESC TEC aerial robotics team participation on the euRathlon 2015 robotics competition. The multi-domain (land, sea and air) search and rescue scenario is described and technical solution adopted is presented with emphasis on the perception system. The calibration of the image based system is addressed. Results from the operational missions performed are also discussed. The aerial autonomous vehicle was able to successfully perform multiple tasks from the aerial reconnaissance and 3D mapping to the identification of leaking pipes, obstructed passages and missing workers. The system was validated a realistic operational scenario and won the Grand Challenge in cooperation with land and marine robotics partner teams. This challenge was the first time that a real time collaborative team of aerial, land and marine robots was deployed successfully in a search and rescue mission.

2017

Autonomous Systems in remote areas of the Ocean using BLUECOM plus communication network

Authors
Ferreira, H; Silva, F; Sousa, P; Matias, B; Faria, A; Oliveira, J; Almeida, JM; Martins, A; Silva, E;

Publication
OCEANS 2017 - ANCHORAGE

Abstract
The authors present a series of sea trails with autonomous systems using a long-range communication network. The continuous monitoring of the oceans and realtime data gathering/monitoring is a key issue in future marine challenges. To have long range communication, between land and ships at tens of kilometers', the authors used the BlueCom+ project research trials and tested their robotic systems. Bluecom+ project intends to fill the gap of long range communication with high bandwidth. It was demonstrated the usefulness of the system using autonomous systems, such as a small unmanned vehicle (ROAZ USV) for bathymetric mapping and tested an underwater acoustic positioning and communications system. © 2017 Marine Technology Society.

2017

Cooperative Deep Water Seafloor Mapping with Heterogeneous Robotic Platforms

Authors
Cruz, N; Abreu, N; Almeida, J; Almeida, R; Alves, J; Dias, A; Ferreira, B; Ferreira, H; Gonçalves, C; Martins, A; Melo, J; Pinto, A; Pinto, V; Silva, A; Silva, H; Matos, A; Silva, E;

Publication
OCEANS 2017 - ANCHORAGE

Abstract
This paper describes the PISCES system, an integrated approach for fully autonomous mapping of large areas of the ocean in deep waters. A deep water AUV will use an acoustic navigation system to compute is position with bounded error. The range limitation will be overcome by a moving baseline scheme, with the acoustic sources installed in robotic surface vessels with previously combined trajectories. In order to save power, all systems will have synchronized clocks and implement the One Way Travel Time scheme. The mapping system will be a combination of an off-the-shelf MBES with a new long range bathymetry system, with a source on a moving surface vessel and the receivers on board the AUV. The system is being prepared to participate in round one of the XPRIZE challenge.

2019

LiDAR-Based Real-Time Detection and Modeling of Power Lines for Unmanned Aerial Vehicles

Authors
Azevedo, F; Dias, A; Almeida, J; Oliveira, A; Ferreira, A; Santos, T; Martins, A; Silva, E;

Publication
SENSORS

Abstract
The effective monitoring and maintenance of power lines are becoming increasingly important due to a global growing dependence on electricity. The costs and risks associated with the traditional foot patrol and helicopter-based inspections can be reduced by using UAVs with the appropriate sensors. However, this implies developing algorithms to make the power line inspection process reliable and autonomous. In order to overcome the limitations of visual methods in the presence of poor light and noisy backgrounds, we propose to address the problem of power line detection and modeling based on LiDAR. The PL2DM, Power Line LiDAR-based Detection and Modeling, is a novel approach to detect power lines. Its basis is a scan-by-scan adaptive neighbor minimalist comparison for all the points in a point cloud. The power line final model is obtained by matching and grouping several line segments, using their collinearity properties. Horizontally, the power lines are modeled as a straight line, and vertically as a catenary curve. Using a real dataset, the algorithm showed promising results both in terms of outputs and processing time, adding real-time object-based perception capabilities for other layers of processing.

2019

3D UNDERWATER MINE MODELLING IN THE 'VAMOS' PROJECT

Authors
Bleier, M; Almeida, C; Ferreira, A; Pereira, R; Matias, B; Almeida, J; Pidgeon, J; van der Lucht, J; Schilling, K; Martins, A; Silva, E; Nuechter, A;

Publication
UNDERWATER 3D RECORDING AND MODELLING: A TOOL FOR MODERN APPLICATIONS AND CH RECORDING

Abstract
The project Viable Alternative Mine Operating System ('VAMOS') develops a novel underwater mining technique for extracting inland mineral deposits in flooded open-cut mines. From a floating launch and recovery vessel a remotely-operated underwater mining vehicle with a roadheader cutting machine is deployed. The cut material is transported to the surface via a flexible riser hose. Since there is no direct intervisibility between the operator and the mining machine, the data of the sensor systems can only be perceived via a computer interface. Therefore, part of the efforts in the project focus on enhancing the situational awareness of the operator by providing a 3D model of the mine combined with representations of the mining equipment and sensor data. We present a method how a positioning and navigation system, perception system and mapping system can be used to create a replica of the physical system and mine environment in Virtual Reality (VR) in order to assist remote control. This approach is beneficial because it allows visualizing different sensor information and data in a consistent interface, and enables showing the complete context of the mining site even if only part of the mine is currently observed by surveying equipment. We demonstrate how the system is used during tele-operation and show results achieved during the field trials of the complete system in Silvermines, Ireland.

2019

Development of an autonomous biosampler to capture in situ aquatic microbiomes

Authors
Ribeiro, H; Martins, A; Goncalves, M; Guedes, M; Tomasino, MP; Dias, N; Dias, A; Mucha, AP; Carvalho, MF; Almeida, CMR; Ramos, S; Almeida, JM; Silva, E; Magalhaes, C;

Publication
PLOS ONE

Abstract
The importance of planktonic microbial communities is well acknowledged, since they are fundamental for several natural processes of aquatic ecosystems. Microorganisms naturally control the flux of nutrients, and also degrade and recycle anthropogenic organic and inorganic contaminants. Nevertheless, climate change effects and/or the runoff of nutrients/pollutants can affect the equilibrium of natural microbial communities influencing the occurrence of microbial pathogens and/or microbial toxin producers, which can compromise ecosystem environmental status. Therefore, improved microbial plankton monitoring is essential to better understand how these communities respond to environmental shifts. The study of marine microbial communities typically involves highly cost and time-consuming sampling procedures, which can limit the frequency of sampling and data availability. In this context, we developed and validated an in situ autonomous biosampler (IS-ABS) able to collect/concentrate in situ planktonic communities of different size fractions (targeting prokaryotes and unicellular eukaryotes) for posterior genomic, metagenomic, and/or transcriptomic analysis at a home laboratory. The IS-ABS field prototype is a small size and compact system able to operate up to 150 m depth. Water is pumped by a micropump (TCS MG2000) through a hydraulic circuit that allows in situ filtration of environmental water in one or more Sterivex filters placed in a filter cartridge. The IS-ABS also includes an application to program sampling definitions, allowing pre-setting configuration of the sampling. The efficiency of the IS-ABS was tested against traditional laboratory filtration standardized protocols. Results showed a good performance in terms of DNA recovery, as well as prokaryotic (16S rDNA) and eukaryotic (18S rDNA) community diversity analysis, using either methodologies. The IS-ABS automates the process of collecting environmental DNA, and is suitable for integration in water observation systems, what will contribute to substantially increase biological surveillances. Also, the use of highly sensitive genomic approaches allows a further study of the diversity and functions of whole or specific microbial communities.

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