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- 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.
- 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.
- 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.
- 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.