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Publications

Publications by Alfredo Martins

2007

Forest fire detection with a small fixed wing autonomous aerial vehicle

Authors
Martins, A; Almeida, J; Almeida, C; Figueiredo, A; Santos, F; Bento, D; Silva, H; Silva, E;

Publication
IFAC Proceedings Volumes (IFAC-PapersOnline)

Abstract
In this work a forest fire detection solution using small autonomous aerial vehicles is proposed. The FALCOS unmanned aerial vehicle developed for remote-monitoring purposes is described. This is a small size UAV with onboard vision processing and autonomous flight capabilities. A set of custom developed navigation sensors was developed for the vehicle. Fire detection is performed through the use of low cost digital cameras and near-infrared sensors. Test results for navigation and ignition detection in real scenario are presented.

2003

Specification of multiple AUV strategies for search of freshwater oceanic sources

Authors
Silva, EP; Martins, AM; Almeida, JM; Sousa, JB; Pereira, FL;

Publication
OCEANS 2003 MTS/IEEE: CELEBRATING THE PAST...TEAMING TOWARD THE FUTURE

Abstract
System and mission requirements for the use of Autonomous Underwater Vehicles (AUV) were defined. A requirement analysis was done having in mind the definition of search methodologies involving multiple cooperating vehicles. Control and navigation issues were addressed. Various search strategies were proposed and analyzed in terms of control, navigation and overall system requirements.

2004

Hybrid maneuver for gradient search with multiple coordinated AUVs

Authors
Martins, A; Almeida, JM; Silva, E; Pereira, FL;

Publication
IFAC Proceedings Volumes (IFAC-PapersOnline)

Abstract
This work presents a hybrid maneuver for gradient search with multiple AUV's. The mission consists in following a gradient field in order to locate the source of a hydrothermal vent or underwater freshwater source. The formation gradient search exploits the environment structuring by the phenomena to be studied. The ingredients for coordination are the payload data collected by each vehicle and their knowledge of the behaviour of other vehicles and detected formation distortions. Copyright © 2004 IFAC. Copyright © 2004 IFAC

2006

Simultaneous control, navigation and target tracking for robotic formations

Authors
Almeida, JM; Martins, A; Silva, EP; Pereira, FL;

Publication
IEEE International Conference on Multisensor Fusion and Integration for Intelligent Systems

Abstract
This paper describes a preliminary and innovative approach to integrated cooperative control and navigation of multi robots dynamic formations that encompasses the simultaneous tracking of opponent team players in robotic football games. Unlike traditional approaches that use self-localization to distribute object position estimates, a coordinated approach to cooperative formation navigation is proposed. The control architecture is based in a hierarchic hybrid systems approach, where distributed maneuvers allow simultaneous navigation and coordination. Our main contributions reside in an integrated control and navigation design framework yielding cooperative localization maneuvers and also some specific maneuver results on both formation estimation and global localization of two robots and two landmarks with bearing only measurements. © 2006 IEEE.

2012

Vision-Based Assisted Teleoperation for Inspection Tasks with a Small ROV

Authors
Costa, MJ; Goncalves, P; Martins, A; Silva, E;

Publication
2012 OCEANS

Abstract
It is well-known that ROVs require human intervention to guarantee the success of their assignment, as well as the equipment safety. However, as its teleoperation is quite complex to perform, there is a need for assisted teleoperation. This study aims to take on this challenge by developing vision-based assisted teleoperation maneuvers, since a standard camera is present in any ROV. The proposed approach is a visual servoing solution, that allows the user to select between several standard image processing methods and is applied to a 3-DOF ROV. The most interesting characteristic of the presented system is the exclusive use of the camera data to improve the teleoperation of an underactuated ROV. It is demonstrated through the comparison and evaluation of standard implementations of different vision methods and the execution of simple maneuvers to acquire experimental results, that the teleoperation of a small ROV can be drastically improved without the need to install additional sensors.

2009

Manoeuvre Based Mission Control System for Autonomous Surface Vehicle

Authors
Dias, N; Almeida, C; Ferreira, H; Almeida, J; Martins, A; Dias, A; Silva, E;

Publication
OCEANS 2009 - EUROPE, VOLS 1 AND 2

Abstract
In this work the mission control and supervision system developed for the ROAZ Autonomous Surface Vehicle is presented. Complexity in mission requirements coupled with flexibility lead to the design of a modular hierarchical mission control system based on hybrid systems control. Monitoring and supervision control for a vehicle such as ROAZ mission is not an easy task using tools with low complexity and yet powerful enough. A set of tools were developed to perform both on board mission control and remote planning and supervision. "ROAZ- Mission Control" was developed to be used in support to bathymetric and security missions performed in river and at seas.

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