Design of an embedded microcomputer based mini quadrotor UAV

This paper describes the design and realization of a mini quadrotor UAV (Unmanned Aerial Vehicle) that has been initiated in the Systems and Control Laboratory at the Computer and Automation Research institute of the Hungarian Academy of Science in collaboration with control departments of the Budapest University of Technology and Economics. The mini quadrotor UAV is intended to use in several areas such as camera-based air-surveillance, traffic control, environmental measurements, etc. The paper focuses upon the embedded microcomputer-based implementation of the mini UAV, describes the elements of the implementation, the tools realized for mathematical model building, as well as obtains a brief outline of the control design

Simulation of Mixed Critical In-vehicular Networks

Future automotive applications ranging from advanced driver assistance to autonomous driving will largely increase demands on in-vehicular networks. Data flows of high bandwidth or low latency requirements, but in particular many additional communication relations will introduce a new level of complexity to the in-car communication system. It is expected that future communication backbones which interconnect sensors and actuators with ECU in cars will be built on Ethernet technologies. However, signalling from different application domains demands for network services of tailored attributes, including real-time transmission protocols as defined in the TSN Ethernet extensions. These QoS constraints will increase network complexity even further. Event-based simulation is a key technology to master the challenges of an in-car network design. This chapter introduces the domain-specific aspects and simulation models for in-vehicular networks and presents an overview of the car-centric network design process. Starting from a domain specific description language, we cover the corresponding simulation models with their workflows and apply our approach to a related case study for an in-car network of a premium car

Distributing Cyber-Physical Systems Simulation: The Satellite Constellation Case

The goal of this position paper is to contribute for the improving of Cyber-Physical System (CPS) simulations by introducing distribution. CPS use computations andcommunication tightly interacting with physical processes. So a CPS simulation needs to tackle with three kinds of simulations: the computational simulation, the physical simulation, and the communication simulation. In this paper, we will focus on the communication simulation, and its interaction with the two others simulations. We will draw a landscape of the existing concepts and technologies for distributing communication simulation, and then propose an architecture for interacting with the whole CPS simulation. We will apply this architecture to a simulation of a satellite constellation, where satellites can be simulated with different levels of precision, from the simple generic mathematical model to the heavy-featured CPS simulation

Estudo do impacto de transientes elétricos em protocolos de comunicação em sistemas embarcados

O aumento da complexidade e responsabilidade dos dispositivos embarcados nos veículos hoje, tem orientado os esforços no desenvolvimento de sistemas de controle para que estes sejam mais rápidos, precisos, robustos e principamente seguros. Com isso, estes dispositivos estão levando os protocolos de comunicação a um patamar inédito de exigência, tanto no quesito de capacidade como confiabilidade. Protocolos como CAN, CAN-FD e FlexRay entre outros, tem sido utilizados devido às suas características de segurança e a capacidade de atender aos requisitos temporais dos diversos circuitos embarcados. O desenvolvimento e utilização cada vez mais frequente de dispositivos focados em segurança, fazem com que a comunicação entre os diversos componentes destes dispositivos seja exigida ao máximo, levando à necessidade de respostas confiáveis ao extremo. Sistemas como freios ABS, suspensão ativa, frenagem autonoma de emergência, controle de velocidade e distância adaptativo, entre outros, que envolvem várias ECUs distribuídas ao longo do veículo, dispões de frações de segundo para a reação do sistema, entre o sinal de entrada e a atuação correspondente, demandando uma comunicação segura e tolerante à falhas. Os veículos hoje estão passando por grandes mudanças conceituais, trazendo cada vez mais elementos onde o funcionamento demanda mais energia das fontes de alimentação. Diversos sistemas existentes nos veículos geram ruídos como os Transientes Elétricos Rápidos, ou "Electric Fast Transient" (EFT), que estão presentes nas mais simples operações cotidianas do veículo, como ligar e desligar o farol, o ar condicionado, o limpador de para brisas, ou mesmo o acionamento de iluminação diurna (DRL), etc. Neste trabalho foram realizados diversos ensaios, utilizando ECUs com diferentes funções e protocolos, para identificar a susceptibilidade dos referidos sistemas e os protocolos à presença destes ruídos. Visando atender às normas IEC 62228 e a ISO26262, este trabalho demandou o projeto e construção de dois circuitos eletrônicos diferentes, um circuito observando os dados de tempos de subida e de descida (rise and fall time) dos pulsos de EFT, e outro observando a arquitetura do layout da placa de circuito impresso (PCB), as suas entradas, saídas, componentes, etc. Estes ensaios visaram identificar o quanto estes protocolos são suscetíveis à estes tipos de ruídos, utilizando métricas de análise baseadas nos tempos de latência e variação de jitter dos pacotes de comunicação.The increasing complexity and accountability of embedded devices in vehicles today has driven efforts to develop control systems to make them faster, accuratest, safest, robustest. Thus, these devices are taking communication protocols to an unprecedented level of demand, both in terms of capacity and reliability. Protocols such as CAN, CANFD and FlexRay among others have been used due to their safety characteristics and the ability to meet the time requirements of various embedded circuits. The increasing development and use of safety-focused devices, means that communication between the various components of these devices is required to the utmost, leading to the need for extremely reliable responses. Systems such as ABS brakes, active suspension, autonomous emergency braking, adaptative cruise control, among others, which involve various ECUs distributed throughout the vehicle, have milliseconds for system reaction, between input signal and concrete actuation, requiring safe and failure tolerant communication. Vehicles today are undergoing major conceptual changes, bringing more and more elements whose operation require more energy from power supplies. These systems generate noise such as "Electric Fast Transient" (EFT), which are present in the simplest daily operations of the vehicle, such as turning the headlight on, the air conditioner, the windscreen wiper, or even the daytime running light (DRL), etc. In this work several tests were carried out, using different ECUs with different functions and different protocols to identify the susceptibility of these systems and the protocols to these noises. In order to comply with IEC 62228 and ISO 26262 standards, this work required the design and construction of two different electronic circuits, one circuit observing the rise and fall time data of the EFT pulses, and the other observing the architecture of the printed circuit board (PCB) layout, its inputs and outputs, components, etc. These tests aimed to identify how susceptible these protocols are to these types of noise, using analysis metrics based on latency time and jitter variation of communication packets

Flexible Bus Media Redundancy

DETIThis paper proposes a flexible approach to bus media redundancy in Controller Area Network (CAN) fieldbuses, both to improve the bandwidth by transmitting different traffic in different channels or to promote redundancy by transmitting the same message in more than one channel. Specifically the proposed solution is discussed in the context of Flexible Time-Triggered protocol over CAN (FTTCAN) and inherits the online scheduling flexibility of FTTCAN, enabling on-the-fly modifications of the traffic conveyed in the replicated buses. Flexible bus media redundancy is useful to fulfill application requirements in terms of additional bandwidth or to react to bus failures leading the system to a degraded operational mode, without compromising safety. The arguments for and against flexible bus media redundancy in the context of FTT-CAN are also discussed in detail

Modeling and verifying the FlexRay physical layer protocol with reachability checking of timed automata

In this thesis, I report on the verification of the resilience of the FlexRay automotive bus protocol's physical layer protocol against glitches during message transmission and drifting clocks. This entailed modeling a significant part of this industrially used communictation protocol and the underlying hardware as well as the possible error scenarios in fine detail. Verifying such a complex model with model-checking led me to the development of data-structures and algorithms able to handle the associated complexity using only reasonable resources. This thesis presents such data-structures and algorithms for reachability checking of timed automata. It also present modeling principles enabling the construction of timed automata models that can be efficiently checked, as well as the models arrived at. Finally, it reports on the verified resilience of FlexRay's physical layer protocol against specific patterns of glitches under varying assumptions about the underlying hardware, like clock drift.In dieser Dissertation berichte ich über den Nachweis der Resilienz des Bitübertragungsprotokolls für die physikalische Schicht des FlexRay-Fahrzeugbusprotokolls gegenüber Übertragungsfehlern und Uhrenverschiebung. Dafür wurde es notwendig, einen signifikanten Teil dieses industriell genutzten Kommunikationsprotokolls mit seiner Hardwareumgebung und die möglichen Fehlerszenarien detailliert zu modellieren. Ein so komplexes Modell mittels Modellprüfung zu überprüfen führte mich zur Entwicklung von Datenstrukturen und Algorithmen, die die damit verbundene Komplexität mit vernünftigen Ressourcenanforderungen bewältigen können. Diese Dissertation stellt solche Datenstrukturen und Algorithmen zur Erreichbarkeitsprüfung gezeiteter Automaten vor. Sie stellt auch Modellierungsprinzipien vor, die es ermöglichen, Modelle in Form gezeiteter Automaten zu konstruieren, die effizient überprüft werden können, sowie die erstellten Modelle. Schließlich berichtet sie über die überprüfte Resilienz des FlexRay-Bitübertragungsprotokolls gegenüber spezifischen Übertragungsfehlermustern unter verschiedenen Annahmen über die Hardwareumgebung, wie etwa die Uhrenverschiebung.DFG: SFB/TRR 14 "AVACS - Automatische Verifikation und Analyse komplexer Systeme