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Planning Aggressive Drone Manoeuvres
Publication . Pinto, João Teixeira; Guerreiro, Bruno J.; Cunha, Rita; CTS - Centro de Tecnologia e Sistemas; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; Springer
This paper addresses the problem of performing aggressive manoeuvres by using multirotor vehicles that include passing through any specific point within the full state space of the vehicle. To this end, the design of optimal trajectories considers the dynamical model of the vehicles by numerically integrating it backwards in time, in the manifold where the dynamics evolve, and dividing the manoeuvres into three distinct phases to accommodate any combination of initial, desired, and final states. In the first phase, the vehicles fly from an initial to a launch configuration to achieve the necessary momenta to reach the desired one in the second phase. To ensure the feasibility of executing the second phase, the relation between snap and body torques is exploited by commanding the vehicles to track geodesic curves on SO(3) during the backwards integration. The vehicles are then driven to a final configuration in the third phase. Most existing solutions to execute aggressive and precise manoeuvres with these rotorcraft focus either on the attitude control problem, leaving the position in open-loop, or use different controllers for different sections of the manoeuvre. In this work, a single tracking controller is considered to validate the proposed trajectory planning strategy in a realistic simulation environment, which involves the PX4 firmware, and in a controlled experimental setup. The results demonstrate that accurate tracking of the designed trajectories enables the vehicles to perform 360-degree loops at great speed and manoeuvres that facilitate the exchange of a parcel between two multirotor vehicles during flight.
Prevention of forest fires using computer vision
Publication . Tavares, Afonso Brito Caldeira Viegas; Silvestre, Daniel
The increase in both the number and size of fires demonstrates an urgent need for
new and innovative interventions, not only in firefighting, but also in prevention, since
firefighting is far more efficient when combined with improved prevention strategies.
One of the most effective methods of preventing the spread of fires is to ensure that
fields, especially tree plantations, are regularly trimmed and cleaned, preventing fire from
spreading from the ground to the tree canopy, making it tremendously difficult to control
and extinguish a fire.
The use of videos of tree plantations taken by an Unmanned Aerial Vehicle (UAV) and
the subsequent creation of an algorithm that processes them, with the use of computer
vision and OpenCV algorithms, has the effect of significantly reducing the laborious
task of checking whether parts of a field are cleaned. This process eliminates the need
for human intervention and reliance on a database of images of trees to create a neural
network model.
The script implemented is designed to process and compare two videos, one repre-
senting a clean field of a tree plantation and the other representing the same plantation
after some time (with potential overgrowth). The objective is to identify tree trunks that
are occluded by vegetative growth and require cleaning.
Although further testing of the algorithm is required in order to guarantee its efficacy
in a broader range of scenarios and with a greater quantity of data, the results of this work
are promising.
Fishing effort and enforcement in the Azores Marine Protected Areas
Publication . Moura, Ricardo; Santos, Nuno Pessanha; Catarino, Maria Eduarda; CMA - Centro de Matemática e Aplicações; KeAi Communications Co.
Fishing is a significant global food source, providing protein for millions of people. The Food and Agriculture Organization (FAO) is committed to ensuring access to high-quality food, reducing hunger, and promoting sustainable fisheries to address global population growth and hunger. However, illegal, unreported, and unregulated fishing poses a significant challenge, threatening marine biodiversity and food security. Portugal has the 10th largest Exclusive Economic Zone (EEZ), with waters around mainland Portugal, the Azores, and Madeira. This research focuses on the Azores region, known for its traditional multispecific fishery around the island slopes and seamounts. The region's fisheries face data scarcity issues and complicating effective management. By combining Vessel Monitoring System (VMS) records from 2016 to 2022 and Portuguese Navy (PoN) Fiscalization Reports (FISCREP) from 2015 to 2022, it was possible to use appropriate metrics to characterize the fishing effort and analyze the effectiveness of the inspections conducted in the Azores EEZ. The Total Boat-Meter (TBM) metric combines the number and length of boats to quantify the fishing effort better. The analysis shows that the fishing effort in the protected areas is very high, highlighting the pressure on the protected ecosystems. The findings aim to assist regulatory institutions and researchers in assessing fishing pressure and promoting sustainable fisheries management in the Azores to preserve marine ecosystems.
Seagrass space occupation efficiency is key for their role as ecosystem engineers and ecological indicators
Publication . Vieira, Vasco M.N.C.S.; Santos, Rafael; Leitão-Silva, David; Veronez, Arthur; Neves, Joana M.; Nogueira, Marta; Brito, Ana; Cereja, Rui; Creed, Joel C.; Bertelli, Chiara M.; Samper-Villarreal, Jimena; Bartilotti, Cátia; Lobo-Arteaga, Jorge; MARE - Centro de Ciências do Mar e do Ambiente; UCIBIO - Applied Molecular Biosciences Unit; Springer Nature
Studies for the preservation of seagrass beds biotopes have met difficulties in establishing appropriate methods assessing their health. We tested the efficiency of space occupation by seagrasses scattered worldwide (dgrass index), which proved to be dependent on clonal growth form and morphometric plasticity. dgrass correlated with the above-ground to below-ground biomass ratio. However, the latter was misleading when high ratios resulted from low below-ground biomass. Nutrient Posphate-limitations were revealed in situations of theoretical Nitrogen-limitation. Enhanced nutrient supply benefitted seagrasses only up to a threshold after which it became detrimental. Better nurtured, healthier meadows with denser canopies increased the organic matter in the sediment and had associated greater abundances of benthic macrofauna. Hence, seagrass biotopes could benefit from moderate anthropogenic nutrient additions. However, organic matter above ≈6% and/or reduced riverine discharges (dams upstream and climate-change-related droughts) were detrimental to healthy meadows, jeopardizing ecosystem services such as macrofauna abundances and carbon sinks.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
Concurso para Atribuição do Estatuto e Financiamento de Laboratórios Associados (LA)
Número da atribuição
LA/P/0083/2020