Real-time performance analysis of a QoS based industrial embedded network

AFDX serves as a backbone network for transmission of critical avionic flows. This network is certified thanks to the WCTT analysis using Network Calculus (NC) approach. However, the pessimism introduced by NC approach often leads to an over-sized and eventually an underutilized network. The manufacturers envision to better use the available network resources by increasing occupancy rate of the AFDX network by allowing additional traffic from other critical and non-critical functions. Such harmonization of AFDX network with mixed criticality flows necessitates the use of QoS mechanism to satisfy the delay constraints in different classes of flow. In this thesis we study such QoS-aware network, in particular, based on DRR and WRR scheduling. We propose an optimal bandwidth distribution method that ensures the service required by critical flows while providing maximum service to other non-critical flows. We also propose an optimized NC approach to compute tight delay bounds. Our approach has led to computation of up to 40% tighter bounds, in an industrial AFDX configuration, as compared to the classical approach

Formation control of autonomous vehicles with emotion assessment

Autonomous driving is a major state-of-the-art step that has the potential to transform the mobility of individuals and goods fundamentally. Most developed autonomous ground vehicles (AGVs) aim to sense the surroundings and control the vehicle autonomously with limited or no driver intervention. However, humans are a vital part of such vehicle operations. Therefore, an approach to understanding human emotions and creating trust between humans and machines is necessary. This thesis proposes a novel approach for multiple AGVs, consisting of a formation controller and human emotion assessment for autonomous driving and collaboration. As the interaction between multiple AGVs is essential, the performance of two multi-robot control algorithms is analysed, and a platoon formation controller is proposed. On the other hand, as the interaction between AGVs and humans is equally essential to create trust between humans and AGVs, the human emotion assessment method is proposed and used as feedback to make autonomous decisions for AGVs. A novel simulation platform is developed for navigating multiple AGVs and testing controllers to realise this concept. Further to this simulation tool, a method is proposed to assess human emotion using the affective dimension model and physiological signals such as an electrocardiogram (ECG) and photoplethysmography (PPG). The experiments are carried out to verify that humans' felt arousal and valence levels could be measured and translated to different emotions for autonomous driving operations. A per-subject-based classification accuracy is statistically significant and validates the proposed emotion assessment method. Also, a simulation is conducted to verify AGVs' velocity control effect of different emotions on driving tasks

A multi-robot simulator for the evaluation of formation control algorithms

Autonomous/unmanned driving has the capability to provide numerous benefits such as better traffic management, increased safety, reduced emission, and enhanced transportation network. Once autonomous ground vehicles (AGVs) are deployed, they will have to interact with other such vehicles. Interaction between multiple AGVs is an important area of research where analysis on the performance of algorithms/control schemes of AGVs is carried out. Performing real-world experiments with teams of autonomous vehicles is a challenging task due to cost and complexity. On the other hand, a simulation can emulate reality and provide an inexpensive and less time-consuming development process compared to the real world robots' testing. Therefore, a simulation tool is developed for multi-robot navigation. This simulator is based on open-source Robot Operating Systems (ROS) and natively supported robotics simulator Gazebo

RF Controlled Digital Wireless Camera

In the present scenario cameras are fixed in static position due to which they are able to monitor a limited area. The effective way to increase the coverage area to camera is to design a system which will give the flexibility to move the camera in different directions as per requirements [1]. This paper presents operation and working of wireless video camera system. This system is developed by using USB-camera, microcontroller atmega16A, serial communicator-FTDI232 which is used for communication between computer and micro-controller and vice versa and motor driving circuit. The special feature about this system is that direction of camera can be changed by user in desired direction from the control room using Bluetooth mobile application. So only one camera can cover the large area making the system reliable, cheap and convenient. This type of system can be used in surveillance application, military application and for monitoring purpose [1]

Work in progress paper: pessimism analysis of network calculus approach on AFDX networks

Worst-case delay analysis of real-time networks is mandatory, since distributed real-time applications require bounded end-to-end delays. Switched Ethernet technologies have become popular solutions in the context of real-time systems. Several approaches, based on Network Calculus, trajectories, ..., have been proposed for the worst-case analysis of such technologies. They compute pessimistic upper bounds of end-toend delays. Since this pessimism leads to an over-dimensioning of the network, it is important to quantify the pessimism of the computed upper bounds. In this paper, we propose such a pessimism analysis, based on Network Calculus. In a first step we focus on avionics switched Ethernet network (AFDX) with Fixed Priority/First In First Out (FP/FIFO) scheduling

Analyse de performance temps-réel d'un réseau industriel embarqué à qualité de service

L'AFDX est utilisé comme un réseau fédérateur pour la transmission des flux avioniques critiques. Ce réseau est certifié grâce à l'analyse pire-cas utilisant l'approche Network Calculus (NC). Le pessimisme introduit par NC conduit souvent à un réseau surdimensionné et éventuellement sous-utilisé. Les avionneurs envisagent d'augmenter l'utilisation des ressources du réseau AFDX en ajoutant du trafic supplémentaire provenant d'autres fonctions critiques et non critiques. Le partage du réseau AFDX avec des flux de criticité mixtes nécessite l'utilisation d'un mécanisme de qualité de service (QoS) pour satisfaire les contraintes de délai des différentes classes de flux. Dans cette thèse, nous étudions un tel réseau déployant de la qualité de service, en particulier, basé sur l'ordonnancement DRR et WRR. Nous proposons une méthode optimale de distribution de la bande passante qui assure le service requis par les flux critiques tout en fournissant un service maximisé aux flux non-critiques. Nous proposons également une approche NC optimisée qui, sur une configuration industrielle de réseau AFDX, a permis de réduire les bornes jusqu'à 40%.AFDX serves as a backbone network for transmission of critical avionic flows. This network is certified thanks to the WCTT analysis using Network Calculus (NC) approach. However, the pessimism introduced by NC approach often leads to an over-sized and eventually an underutilized network. The manufacturers envision to better use the available network resources by increasing occupancy rate of the AFDX network by allowing additional traffic from other critical and non-critical functions. Such harmonization of AFDX network with mixed criticality flows necessitates the use of QoS mechanism to satisfy the delay constraints in different classes of flow. In this thesis we study such QoS-aware network, in particular, based on DRR and WRR scheduling. We propose an optimal bandwidth distribution method that ensures the service required by critical flows while providing maximum service to other non-critical flows. We also propose an optimized NC approach to compute tight delay bounds. Our approach has led to computation of up to 40% tighter bounds, in an industrial AFDX configuration, as compared to the classical approach

Formation Control for a Fleet of Autonomous Ground Vehicles: A Survey

Autonomous/unmanned driving is the major state-of-the-art step that has a potential to fundamentally transform the mobility of individuals and goods. At present, most of the developments target standalone autonomous vehicles, which can sense the surroundings and control the vehicle based on this perception, with limited or no driver intervention. This paper focuses on the next step in autonomous vehicle research, which is the collaboration between autonomous vehicles, mainly vehicle formation control or vehicle platooning. To gain a deeper understanding in this area, a large number of the existing published papers have been reviewed systemically. In other words, many distributed and decentralized approaches of vehicle formation control are studied and their implementations are discussed. Finally, both technical and implementation challenges for formation control are summarized

Efficient configuration of a QoS-aware AFDX network with Deficit Round Robin

International audienceAFDX is the de facto communication standard in avionics domain. It is primarily used for the transmission of critical avionic flows. The mandatory certification process requires to upper bound the end-to-end transmission delay for each critical flow. Therefore, worst-case traversal time analysis has been implemented. However, it leads to a very lightly loaded network (up to 10%) as it considers very rare worst-case situations. Introducing a QoS mechanism is often a good solution to improve network utilisation since it allows differentiating critical flows based on their constraints as well as the transmission of less/non-critical flows with bounded impact on critical ones. Deficit Round Robin is such a mechanism and it is envisioned for future avionic networks. Using this mechanism, we propose to share the bandwidth between n − 1 classes for critical flows and one class for non-critical ones. Therefore the contributions of this paper are (1) to propose a quantum assignment that ensures that critical flows always respect their deadlines and maximises the bandwidth for non-critical ones and (2) to propose a heuristic for the distribution of the flows among different classes

Quantum assignment for QoS-aware AFDX network with Deficit Round Robin

International audienceAvionics Full Duplex switched Ethernet (AFDX) is the de facto standard for the transmission of critical avionics flows. It is a specific switched Ethernet solution based on First-in First-out (FIFO) scheduling. Timing constraints have to be guaranteed for such critical flows. The worst-case traversal time analysis introduces some pessimism, leading to a very lightly loaded network: typically less than 10 % of the bandwidth is used. One solution to improve the utilisation of the network is to introduce Quality of Service (QoS) mechanisms. First, it can decrease worst-case delays for the most constrained avionics flows. Second less/non critical additional flows can be transmitted on the network with bounded impact on avionics ones. Deficit Round Robin (DRR) is such a QoS mechanism and it is envisioned for future avionics networks. An optimised WCTT analysis has been proposed for DRR on AFDX, based on network calculus. With DRR, the flow set is divided into classes and each class is allocated a quantum. In each round, transmissions are managed, based on these quanta. Thus delays are significantly impacted by quanta. The contribution of this paper is to propose an efficient quantum assignment for a set of critical avionics flow classes and at most one additional class with less/non critical flows

Work in progress paper: pessimism analysis of network calculus approach on AFDX networks

International audienceWorst-case delay analysis of real-time networks is mandatory, since distributed real-time applications require bounded end-to-end delays. Switched Ethernet technologies have become popular solutions in the context of real-time systems. Several approaches, based on Network Calculus, trajectories, ..., have been proposed for the worst-case analysis of such technologies. They compute pessimistic upper bounds of end-toend delays. Since this pessimism leads to an over-dimensioning of the network, it is important to quantify the pessimism of the computed upper bounds. In this paper, we propose such a pessimism analysis, based on Network Calculus. In a first step we focus on avionics switched Ethernet network (AFDX) with Fixed Priority/First In First Out (FP/FIFO) scheduling