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Projeto de investigação
Laboratory of Robotics and Engineering Systems
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Publicações
A resilient continuous-time consensus method using a switching topology
Publication . Ramos, Guilherme; Silvestre, Daniel; Aguiar, A. Pedro; DEE - Departamento de Engenharia Electrotécnica e de Computadores; Elsevier
This paper addresses the design problem of a resilient consensus algorithm for agents with continuous-time dynamics. The main proposal is that by incorporating a switching mechanism selecting the network topology to avoid malicious nodes from communicating, the remaining nodes will converge to a value closer to the original steady-state without the attacker being present. The switching occurs at discrete-time steps where each node evaluates the reputation score of the neighbors and deactivates/ignores edges in the network. We explore the proposed method with illustrative examples ranging from static topologies to dynamic ones, considering directed and undirected graphs, presenting several attacking scenarios that are successfully mitigated with our method. Finally, we compare the best undetectable attacking strategy and the commonly used approach named MSR, highlighting the advantages of our method.
Cooperative Platooning and Servicing for Spacecraft Formation Flying using Model Predictive Control
Publication . Pereira, Pedro; Guerreiro, Bruno; Lourenço, Pedro; DEE - Departamento de Engenharia Electrotécnica e de Computadores; CTS - Centro de Tecnologia e Sistemas; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias
This paper addresses two complementary problems of spacecraft formation flying, namely spacecraft platooning and on-orbit spacecraft servicing, using Model Predictive Control (MPC). With the proposed solutions, these space formation scenarios can be regarded as a cooperative system composed of several spacecraft with a common goal, which may have clear advantages relative to other approaches. For each application scenario, a different optimization problem and MPC design is presented, including relevant constraints to deal with physical limitations, visibility problems, and also to guarantee a collision-free trajectory from other spacecraft or obstacles. The proposed methods are validated with realistic simulation results, showing that all vehicles demonstrate reliable performance following a given trajectory or goal in a formation, while satisfying all the considered constraints.
Leveraging eXtented Reality & Human-Computer Interaction for User Experi- ence in 360◦ Video
Publication . Bala, Paulo Alexandre Câmara; Nisi, Valentina; Correia, Nuno; Nunes, Duarte
EXtended Reality systems have resurged as a medium for work and entertainment. While
360o video has been characterized as less immersive than computer-generated VR, its
realism, ease of use and affordability mean it is in widespread commercial use. Based
on the prevalence and potential of the 360o video format, this research is focused on
improving and augmenting the user experience of watching 360o video. By leveraging
knowledge from Extented Reality (XR) systems and Human-Computer Interaction (HCI),
this research addresses two issues affecting user experience in 360o video: Attention
Guidance and Visually Induced Motion Sickness (VIMS).
This research work relies on the construction of multiple artifacts to answer the de-
fined research questions: (1) IVRUX, a tool for analysis of immersive VR narrative expe-
riences; (2) Cue Control, a tool for creation of spatial audio soundtracks for 360o video, as
well as enabling the collection and analysis of captured metrics emerging from the user
experience; and (3) VIMS mitigation pipeline, a linear sequence of modules (including
optical flow and visual SLAM among others) that control parameters for visual modi-
fications such as a restricted Field of View (FoV). These artifacts are accompanied by
evaluation studies targeting the defined research questions. Through Cue Control, this
research shows that non-diegetic music can be spatialized to act as orientation for users.
A partial spatialization of music was deemed ineffective when used for orientation. Addi-
tionally, our results also demonstrate that diegetic sounds are used for notification rather
than orientation. Through VIMS mitigation pipeline, this research shows that dynamic
restricted FoV is statistically significant in mitigating VIMS, while mantaining desired
levels of Presence. Both Cue Control and the VIMS mitigation pipeline emerged from a
Research through Design (RtD) approach, where the IVRUX artifact is the product of de-
sign knowledge and gave direction to research. The research presented in this thesis is
of interest to practitioners and researchers working on 360o video and helps delineate
future directions in making 360o video a rich design space for interaction and narrative.
Revolutionizing Ocean Cleanup
Publication . Santos, Nuno Pessanha; Moura, Ricardo; Antunes, Teresa Lourenço; Lobo, Victor; CMA - Centro de Matemática e Aplicações; Information Management Research Center (MagIC) - NOVA Information Management School; NOVA Information Management School (NOVA IMS); MDPI AG
It is of the utmost importance for every country to monitor and control maritime pollution within its exclusive economic zone (EEZ). The European Maritime Safety Agency (EMSA) has developed and implemented the CleanSeaNet (CSN) satellite monitoring system to aid in the surveillance and control of hydrocarbon and hazardous substance spills in the ocean. This system’s primary objective is to alert European Union (EU) coastal states to potential spills within their EEZs, enabling them to take the necessary legal and operational actions. To reduce operational costs and increase response capability, the feasibility of implementing a national network (NN) of unmanned vehicles (UVs), both surface and aerial, was explored using a Portuguese case study. The following approach and analysis can be easily generalized to other case studies, bringing essential knowledge to the field. Analyzing oil spill alert events in the Portuguese EEZ between 2017 and 2021 and performing a strengths, weaknesses, opportunities, and threats (SWOT) analysis, essential information has been proposed for the optimal location of an NN of UVs. The study results demonstrate that integrating spill alerts at sea with UVs may significantly improve response time, costs, and personnel involvement, making maritime pollution combat actions more effective.
Enhancing truck platooning efficiency and safety—A distributed Model Predictive Control approach for lane-changing manoeuvres
Publication . Lourenço, Beatriz; Silvestre, Daniel; DEE - Departamento de Engenharia Electrotécnica e de Computadores; Faculdade de Ciências e Tecnologia (FCT); Elsevier Science B.V., Amsterdam.
The advent of autonomous driving technologies has paved the way for notable advancements in the realm of transportation systems. This paper explores the dynamic field of truck platooning, focusing on the development of a Nonlinear Model Predictive Control (NMPC) approach within a Cooperative Adaptive Cruise Control (CACC) framework. The research tackles the critical challenges in obstacle avoidance and lane-changing manoeuvres. The core contribution of this work lies in the development and implementation of a novel NMPC algorithm tailored to platoon control. This framework integrates a penalty soft constraint to guarantee obstacle avoidance and maintain platoon coherence while optimising control inputs in real-time. Several experiments, including static and dynamic obstacle avoidance scenarios, validate the efficacy of the proposed approach. In all experiments, the vehicles closely follow one another, resulting in smooth trajectories for all system states and control input signals. Even in the event of abrupt braking by the ego vehicle, the platoon remains cohesive. Moreover, the proposed NMPC proves to be computationally efficient when compared to the state-of-the-art.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
6817 - DCRRNI ID
Número da atribuição
UIDB/50009/2020