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007
Publications

2021

Potential Non-Invasive Technique for Accessing Plant Water Contents Using a Radar System

Authors
Santos, LC; dos Santos, FN; Morais, R; Duarte, C;

Publication
Agronomy

Abstract
Sap flow measurements of trees are today the most common method to determine evapotranspiration at the tree and the forest/crop canopy level. They provide independent measurements for flux comparisons and model validation. The most common approach to measure the sap flow is based on intrusive solutions with heaters and thermal sensors. This sap flow sensor technology is not very reliable for more than one season crop; it is intrusive and not adequate for low diameter trunk trees. The non-invasive methods comprise mostly Radio-frequency (RF) technologies, typically using satellite or air-born sources. This system can monitor large fields but cannot measure sap levels of a single plant (precision agriculture). This article studies the hypothesis to use of RF signals attenuation principle to detect variations in the quantity of water present in a single plant. This article presents a well-defined experience to measure water content in leaves, by means of high gains RF antennas, spectrometer, and a robotic arm. Moreover, a similar concept is studied with an off-the-shelf radar solution—for the automotive industry—to detect changes in the water presence in a single plant and leaf. The conclusions indicate a novel potential application of this technology to precision agriculture as the experiments data is directly related to the sap flow variations in plant.

2021

A Review of Pruning and Harvesting Manipulators

Authors
Tinoco, V; Silva, MF; Santos, FN; Rocha, LF; Magalhaes, S; Santos, LC;

Publication
2021 IEEE International Conference on Autonomous Robot Systems and Competitions (ICARSC)

Abstract

2021

Cost-Effective 4DoF Manipulator for General Applications

Authors
Magalhães, SA; Moreira, AP; dos Santos, FN; Dias, J; Santos, L;

Publication
Intelligent Systems and Applications - Proceedings of the 2021 Intelligent Systems Conference, IntelliSys 2021, Amsterdam, The Netherlands, 2-3 September, 2021, Volume 3

Abstract

2021

A Case Study on Improving the Software Dependability of a ROS Path Planner for Steep Slope Vineyards

Authors
Santos, LC; Santos, A; Santos, FN; Valente, A;

Publication
Robotics

Abstract
Software for robotic systems is becoming progressively more complex despite the existence of established software ecosystems like ROS, as the problems we delegate to robots become more and more challenging. Ensuring that the software works as intended is a crucial (but not trivial) task, although proper quality assurance processes are rarely seen in the open-source robotics community. This paper explains how we analyzed and improved a specialized path planner for steep-slope vineyards regarding its software dependability. The analysis revealed previously unknown bugs in the system, with a relatively low property specification effort. We argue that the benefits of similar quality assurance processes far outweigh the costs and should be more widespread in the robotics domain.

2020

A Version of Libviso2 for Central Dioptric Omnidirectional Cameras with a Laser-Based Scale Calculation

Authors
Aguiar, A; Santos, F; Santos, L; Sousa, A;

Publication
Advances in Intelligent Systems and Computing - Robot 2019: Fourth Iberian Robotics Conference

Abstract