J. Almeida

Autonomous bathymetry for risk assessment with ROAZ robotic surface vehicle

The use of unmanned marine robotic vehicles in bathymetric surveys is discussed. This paper presents recent results in autonomous bathymetric missions with the ROAZ autonomous surface vehicle. In particular, robotic surface vehicles such as ROAZ provide an efficient tool in risk assessment for shallow water environments and water land interface zones as the near surf zone in marine coast. ROAZ is an ocean capable catamaran for distinct oceanographic missions, and with the goal to fill the gap were other hydrographic surveys vehicles/systems are not compiled to operate, like very shallow water rivers and marine coastline surf zones. Therefore, the use of robotic systems for risk assessment is validated through several missions performed either in river scenario (in a very shallow water conditions) and in marine coastlines.

A hybrid feedback control system for a nonholonomic car-like vehicle

This paper addresses the design of a hybrid feedback control system enabling a car-like, rectangular vehicle to perform a tight L-shaped turn manoeuvre. This case constitutes an effort towards the definition of a general purpose methodology for hybrid feedback control synthesis. The design effort encompasses the synthesis of a set of modalities and mechanisms to detect relevant events enabling the overall motion coordination so that a global goal is attempted. Simulations of the implemented controller have shown a strong robustness with respect to modeling uncertainty and execution errors.This paper addresses the design of a hybrid feedback control system enabling a car-like, rectangular vehicle to perform a tight L-shaped turn maneuver. This case constitutes an effort towards the definition of a general purpose methodology for hybrid feedback control synthesis. The design effort encompasses the synthesis of a set of modalities and mechanisms to detect relevant events enabling the overall motion coordination so that a global goal is attempted. Simulations of the implemented controller have shown a strong robustness with respect to modeling uncertainty and execution errors.

On the design and implementation of a control architecture for a mobile robotic system

In this article, we describe the analysis, design and implementation of a control architecture for a mobile platform to autonomously carry out transportation, surveillance and inspection tasks in semi-structured industrial environments. Based on a hierarchical structure composed by the organization, coordination and functional levels organized linguistically and structured according to the principle of increasing precision with decreasing intelligence, this control architecture permits the real-time parallel execution of tasks.

On the Use of Residues from the Sustainable Extraction of Heart of Palm in Agglomerated Panels

Residues obtained from the sustainable harvest of heart of palm from pejibaye (Bactris gasipaes) palms can be managed to produce long and chopped fibers. These fibrous residues can be used to manufacture agglomerated panels and also serve as reinforcement in polymer–matrix composites. In this work, the characteristics of pejibaye fibrous residues are commented and the flexural mechanical properties of agglomerated panels made with these residues are determined and compared with the properties of conventional wood-based agglomerated panels. Also, panels using both pejibaye residues and residues from coconut plantations were manufactured and their flexural mechanical behavior was determined and compared to panels manufactured using only pejibaye residue. The results obtained show that the flexural mechanical properties of pejibaye agglomerated panels fall within the boundaries established by international standards for interior use (general applications–dry conditions). The hybrid coir/pejibaye panel showed the best set of properties, presenting a performance better than the agglomerated panels manufactured with only one kind of fiber.

Air and underwater survey of water enclosed spaces for VAMOS! Project

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 within the context of the European research project VAMOS with the objective of developing robotic tools for efficient underwater mining.

On the design and implementation of a mobile robotic system

Describes the effort being carried out in the analysis, design and implementation of the control architecture for a mobile platform for autonomous transportation, surveillance and inspection in structured and semi-structured industrial environments. The control architecture is based in a hierarchical structure organized linguistically permitting the real-time parallel execution of tasks. This architecture is composed of three levels, organization, coordination and functional, structured according to the increasing precision with decreasing intelligence principle.