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- A Drone Secure Handover Architecture validated in a Software in the Loop EnvironmentPublication . Vasconcelos Filho, Ênio; Gomes, Filipe; Monteiro, Stéphane; Penna, Sergio; Koubaa, Anis; Tovar, Eduardo; Severino, RicardoThe flight and control capabilities of uncrewed aerial vehicles (UAVs) have increased significantly with recent research for civilian and commercial applications. As a result, these devices are becoming capable of flying ever greater distances, accomplishing flights beyond line of sight (BVLOS). However, given the need for safety guarantees, these flights are increasingly subject to regulations. Handover operations between controllers and the security of the exchanged data are a challenge for implementing these devices in various applications. This paper presents a secure handover architecture between control stations, using a Software in the Loop (SIL) model to validate the adopted strategies and mitigate the time between simulation and real systems implementations. This architecture is developed in two separate modules that perform the security and handover processes. Finally, we validate the proposed architecture with several drone flights on a virtual testbed.
- Edge-aided V2X collision avoidance with platoons: Towards a hybrid evaluation toolsetPublication . Pereira, João; Kurunathan, Harrison; Filho, Ênio; Santos, Pedro M.Infrastructure-brokered collision avoidance is an Intelligent Transportation Systems (ITS) application built on top of Vehicle-to-Everything (V2X) links. An edge-hosted ITS service receives information from road-side sensors (or CAM messages in V2X-enabled vehicles) and detects impending collisions where vehicles cannot sense or contact each other directly. If so happens, it issues a warning message through network-to-vehicle links. Another relevant ITS application is platooning, through which vehicles following each other closely can benefit of improved fuel economy, and that can be further enhanced through communication. In case of emergency braking in platoons, the response times of network and edge-hosted services must be minimal to ensure no collision amongst the platoon or any other road user. In this paper we present the implementation of a simulation framework tailored (but not limited) to evaluate the presented use-case. This complex and multi-layered use-case can be handled by a dedicated ITS service that leverages the sensing, radio and computing resources available at infrastructure and vehicles, and requires a realistic evaluation framework prior to deployment. Such framework is mostly based on simulation, albeit, to the extent possible, actual devices or services should be used; the present work is a step towards that hybrid setup.
- A WSSL Implementation for Critical Cyber-Physical Systems ApplicationsPublication . Rocha, Márcia; Vasconcelos Filho, Ênio; Alves, Fernando; Penna, Sergio; Santos, Pedro Miguel; Tovar, EduardoThe advancements in wireless communication technologies have enabled unprecedented pervasiveness and ubiquity of Cyber-Physical Systems (CPS). Such technologies can now empower true Systemsof-Systems, which cooperate to achieve more complex and efficient functionalities. However, for CPS applications to become a reality, safety and security must be guaranteed, particularly in critical systems, since they rely on open communication systems prone to intentional and non-intentional interferences. We propose designing a Wireless Safety and Security Layer (WSSL) architecture to be implemented in critical CPS applications to address these issues. WSSL increases the reliability of these critical communications by enabling the detection of communication errors. Furthermore, it increases the CPS security using a message signature process that uniquely identifies the sender. So, we present the WSSL architecture and its implementation over an MQTT protocol. We prove that WSSL does not significantly increase the system transmission costs and demonstrate its capability to ensure safety and security, allowing it to be used in any general or critical CPS.
- Towards a Cooperative Robotic Platooning TestbedPublication . Vasconcelos Filho, Ênio; Nuno, Guedes; Mestre, Miguel; Vieira, Bruno; Severino, Ricardo; Koubaa, Anis; Tovar, EduardoThe deployment of information and communication technologies in vehicles and into the transportation infrastructure in general, holds the promise of significant improvements to traffic safety and efficiency. The ETSI ITS-G5 standard presents itself as a viable and already available solution, to enable such intelligent social and mobility scenarios in the near future, including cooperative and autonomous vehicle platooning. However, the usage of wireless communications in safety-critical scenarios poses several challenges, and their reliability and safety must be adequately tested and validated. To do this, the safety concerns and cost of relying on real vehicles is prohibitive for early deployments. A solution lies in the use of robotic platforms, since these are relatively cheaper and allow to partially test real platforms and components, as well as different control mechanisms. This work presents the development of a 1/10 scale Cooperative Platooning Robotic Testbed with such aim. Real ITS-G5 On Board Units (OBU) were integrated in the vehicles for communications support and a cooperative control algorithm that solely relies on communications was successfully implemented.
- Improving the Performance of Cooperative Platooning with Restricted Message Trigger ThresholdsPublication . Vasconcelos Filho, Ênio; Santos, Pedro Miguel; Severino, Ricardo; Koubaa, Anis; Tovar, EduardoCooperative Vehicular Platooning (Co-VP) is one of the most prominent and challenging applications of Intelligent Traffic Systems. To support such vehicular communications, the ETSI ITS G5 standard specifies event-based communication profiles, triggered by kinematic parameters such as speed. The standard defines a set of threshold values for such triggers but no careful assessment in realistic platooning scenarios has been done to confirm the suitability of such values. In this work, we investigate the safety and performance limitations of such parameters in a realistic platooning co-simulation environment. We then propose more conservative threshold values, that we formalize as a new profile, and evaluate their impact in the longitudinal and lateral behaviour of a vehicular platoon as it carries out complex driving scenarios. Furthermore, we analyze the overhead introduced in the network by applying the new threshold values. We conclude that a pro-active message transmission scheme leads to improved platoon performance for highway scenarios, notably an increase greater than 40% in the longitudinal performance of the platoon, while not incurring in a significant network overhead. The obtained results also demonstrated an improved platoon performance for semi-urban scenarios, including obstacles and curves, where the heading error decreases in 26%, with slight network overhead.
- COPADRIVe - A Realistic Simulation Framework for Cooperative Autonomous Driving ApplicationsPublication . Vieira, Bruno; Severino, Ricardo; Vasconcelos Filho, Ênio; Koubaa, Anis; Tovar, EduardoSafety-critical cooperative vehicle applications such as platooning, require extensive testing, however, the complexity and cost involved in this process, increasingly demands for realistic simulation tools to ease the validation of such technologies, helping to bridge the gap between development and real-word deployment. In this paper we propose a realistic co-simulation framework for cooperative vehicles, that integrates Gazebo, an advanced robotics simulator, with the OMNeT++ network simulator, over the Robot Operating System (ROS) framework, supporting the simulation of advanced cooperative applications such as platooning, in realistic scenarios.
- Cooperative Vehicular Platooning: A Multi- Dimensional Survey Towards Enhanced Safety, Security and ValidationPublication . Vasconcelos Filho, Ênio; Santos, Pedro Miguel; Koubaa, Anis; Tovar, Eduardo; Severino, RicardoCooperative Vehicular Platooning (Co-VP) is a paradigmatic example of a Cooperative Cyber-Physical System (Co-CPS), which holds the potential to vastly improve road safety by partially removing humans from the driving task. However, the challenges are substantial, as the domain involves several topics, such as control theory, communications, vehicle dynamics, security, and traffic engineering, that must be coupled to describe, develop and validate these systems of systems accurately. This work presents a comprehensive survey of significant and recent advances in Co-VP relevant fields. We start by overviewing the work on control strategies and underlying communication infrastructures, focusing on their interplay. We also address a fundamental concern by presenting a cyber-security overview regarding these systems. Furthermore, we present and compare the primary initiatives to test and validate those systems, including simulation tools, hardware-in-the-loop setups, and vehicular testbeds. Finally, we highlight a few open challenges in the Co-VP domain. This work aims to provide a fundamental overview of highly relevant works on Co-VP topics, particularly by exposing their inter-dependencies, facilitating a guide that will support further developments in this challenging field.
- Development of a Hardware in the Loop Ad- Hoc Testbed for Cooperative Vehicles PlatooningPublication . Vasconcelos Filho, Ênio; Mendes, Bruno; Santos, Pedro M.; Tovar, EduardoCooperative Cyber-Physical Devices (Co-CPS) are reaching into the most diverse areas and pose new integration challenges. This is particularly true between cooperative autonomous machines, where safety and reliability must often be guaranteed without human presence. Among these scenarios, Cooperative Vehicular Platooning (Co-VP) applications present an exciting promise: improving road occupation, reducing accidents, and providing fuel savings. However, due to their high complexity and safety-critical characteristics, these applications must be validated to ensure their reliability before being applied in real scenarios, particularly regarding their underlying communication transactions. This paper presents an architecture for validating a Co-VP system via Hardware In the Loop (HIL) integration of IEEE 802.11 communications, and co-simulation support of a 3D simulator. We propose a use case with one scenario of communication profile according to the ETSI IT-G5 model and information exchange frequencies between the vehicles. Through these scenarios that mimic realistic conditions of Co-VP applications, we observe the impacts of such variations on the number of messages, network delays, and lateral and longitudinal platoon errors.
- A Dynamic Mode Decomposition approach with Hankel blocks to forecast multi-channel temporal seriesPublication . Vasconcelos Filho, Ênio; Lopes dos Santos, PauloForecasting is a task with many concerns, such as the size, quality, and behavior of the data, the computing power to do it, etc. This letter proposes the dynamic mode decomposition (DMD) as a tool to predict the annual air temperature and the sales of a stores’ chain. The DMD decomposes the data into its principal modes, which are estimated from a training data set. It is assumed that the data is generated by a linear time-invariant high order autonomous system. These modes are useful to find the way the system behaves and to predict its future states, without using all the available data, even in a noisy environment. The Hankel block allows the estimation of hidden oscillatory modes, by increasing the order of the underlying dynamical system. The proposed method was tested in a case study consisting of the long term prediction of the weekly sales of a chain of stores. The performance assessment was based on the best fit percentage index. The proposed method is compared with three neural network-based predictors.
- An Integrated Lateral and Longitudinal Look Ahead Controller for Cooperative Vehicular PlatooningPublication . Vasconcelos Filho, Ênio; Koubaa, Anis; Severino, Ricardo; Tovar, EduardoCooperative Vehicular Platooning (CoVP), has been emerging as a challenging Intelligent Traffic Systems application, promising to bring-about several safety and societal benefits. Relying on V2V communications to control such cooperative and automated actions brings several advantages. In this work, we present a Look Ahead PID controller for CoVP that solely relies upon V2V communications, together with a method to reduce the disturbance propagation in the platoon. The platooning controller also implements a solution to solve the cutting corner problem, keeping the platooning alignment. We evaluate its performance and limitations in realistic simulation scenarios, analyzing the stability and lateral errors of the CoVP, proving that such V2V enabled solutions can be effectively implemented.