Services for safety-critical applications on dual-scheduled TDMA networks

Tese de doutoramento. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 200

Safety-Critical Communication in Avionics

The aircraft of today use electrical fly-by-wire systems for manoeuvring. These safety-critical distributed systems are called flight control systems and put high requirements on the communication networks that interconnect the parts of the systems. Reliability, predictability, flexibility, low weight and cost are important factors that all need to be taken in to consideration when designing a safety-critical communication system. In this thesis certification issues, requirements in avionics, fault management, protocols and topologies for safety-critical communication systems in avionics are discussed and investigated. The protocols that are investigated in this thesis are: TTP/C, FlexRay and AFDX, as a reference protocol MIL-STD-1553 is used. As reference architecture analogue point-to-point is used. The protocols are described and evaluated regarding features such as services, maturity, supported physical layers and topologies.Pros and cons with each protocol are then illustrated by a theoretical implementation of a flight control system that uses each protocol for the highly critical communication between sensors, actuators and flight computers.The results show that from a theoretical point of view TTP/C could be used as a replacement for a point-to-point flight control system. However, there are a number of issues regarding the physical layer that needs to be examined. Finally a TTP/C cluster has been implemented and basic functionality tests have been conducted. The plan was to perform tests on delays, start-up time and reintegration time but the time to acquire the proper hardware for these tests exceeded the time for the thesis work. More advanced testing will be continued here at Saab beyond the time frame of this thesis

A robust, reliable and deployable framework for In-vehicle security

Cyber attacks on financial and government institutions, critical infrastructure, voting systems, businesses, modern vehicles, etc., are on the rise. Fully connected autonomous vehicles are more vulnerable than ever to hacking and data theft. This is due to the fact that the protocols used for in-vehicle communication i.e. controller area network (CAN), FlexRay, local interconnect network (LIN), etc., lack basic security features such as message authentication, which makes it vulnerable to a wide range of attacks including spoofing attacks. This research presents methods to protect the vehicle against spoofing attacks. The proposed methods exploit uniqueness in the electronic control unit electronic control unit (ECU) and the physical channel between transmitting and destination nodes for linking the received packet to the source. Impurities in the digital device, physical channel, imperfections in design, material, and length of the channel contribute to the uniqueness of artifacts. I propose novel techniques for electronic control unit (ECU) identification in this research to address security vulnerabilities of the in-vehicle communication. The reliable ECU identification has the potential to prevent spoofing attacks launched over the CAN due to the inconsideration of the message authentication. In this regard, my techniques models the ECU-specific random distortion caused by the imperfections in digital-to-analog converter digital to analog converter (DAC), and semiconductor impurities in the transmitting ECU for fingerprinting. I also model the channel-specific random distortion, impurities in the physical channel, imperfections in design, material, and length of the channel are contributing factors behind physically unclonable artifacts. The lumped element model is used to characterize channel-specific distortions. This research exploits the distortion of the device (ECU) and distortion due to the channel to identify the transmitter and hence authenticate the transmitter.Ph.D.College of Engineering & Computer ScienceUniversity of Michigan-Dearbornhttps://deepblue.lib.umich.edu/bitstream/2027.42/154568/1/Azeem Hafeez Final Disseration.pdfDescription of Azeem Hafeez Final Disseration.pdf : Dissertatio

Formal Modelling and Verification of the Clock Synchronization Algorithm of FlexRay

The hundreds of electronic control devices used in an automotive system can effectively communicate with one another, thanks to an in-vehicle network (IVN) like FlexRay. Even though every node in the network will be running on its local clock, a global notion of time is essential. The clock synchronisation algorithm accomplishes this global time between the nodes in FlexRay. In this era of self-driving cars, the vehicle’s safety is paramount. For the vehicle to operate safely and smoothly, timely communication of information is critical, and the clock synchronisation algorithm plays a vital role in this. It is essential to formally test the clock synchronisation algorithm’s correctness. This paper attempts to model and verify the clock synchronisation algorithm of FlexRay using formal methods, which in turn enhance the reliability of safety-critical automotive systems. The clock synchronisation is modelled as a network of six timed automata in the UPPAAL model checker. Three system models were developed, a model for an ideal clock, another for a drifting clock, and a third model considering propagation delay. The precision of the clocks is verified to be within the prescribed limits. Simulation studies are also conducted on the model to ensure that the clock’s drift is always within the precision

In-vehicle communication networks : a literature survey

The increasing use of electronic systems in automobiles instead of mechanical and hydraulic parts brings about advantages by decreasing their weight and cost and providing more safety and comfort. There are many electronic systems in modern automobiles like antilock braking system (ABS) and electronic brakeforce distribution (EBD), electronic stability program (ESP) and adaptive cruise control (ACC). Such systems assist the driver by providing better control, more comfort and safety. In addition, future x-by-wire applications aim to replace existing braking, steering and driving systems. The developments in automotive electronics reveal the need for dependable, efficient, high-speed and low cost in-vehicle communication. This report presents the summary of a literature survey on in-vehicle communication networks. Different in-vehicle system domains and their requirements are described and main invehicle communication networks that have been used in automobiles or are likely to be used in the near future are discussed and compared with key references

VEGa : a high performance vehicular Ethernet gateway on hybrid FPGA

Modern vehicles employ a large amount of distributed computation and require the underlying communication scheme to provide high bandwidth and low latency. Existing communication protocols like Controller Area Network (CAN) and FlexRay do not provide the required bandwidth, paving the way for adoption of Ethernet as the next generation network backbone for in-vehicle systems. Ethernet would co-exist with safety-critical communication on legacy networks, providing a scalable platform for evolving vehicular systems. This requires a high-performance network gateway that can simultaneously handle high bandwidth, low latency, and isolation; features that are not achievable with traditional processor based gateway implementations. We present VEGa, a configurable vehicular Ethernet gateway architecture utilising a hybrid FPGA to closely couple software control on a processor with dedicated switching circuit on the reconfigurable fabric. The fabric implements isolated interface ports and an accelerated routing mechanism, which can be controlled and monitored from software. Further, reconfigurability enables the switching behaviour to be altered at run-time under software control, while the configurable architecture allows easy adaptation to different vehicular architectures using high-level parameter settings. We demonstrate the architecture on the Xilinx Zynq platform and evaluate the bandwidth, latency, and isolation using extensive tests in hardware

Automotive embedded systems software reprogramming

This thesis was submitted for the degree of Doctor of Philosophy and was awarded by Brunel UniversityThe exponential growth of computer power is no longer limited to stand alone computing systems but applies to all areas of commercial embedded computing systems. The ongoing rapid growth in intelligent embedded systems is visible in the commercial automotive area, where a modern car today implements up to 80 different electronic control units (ECUs) and their total memory size has been increased to several hundreds of megabyte. This growth in the commercial mass production world has led to new challenges, even within the automotive industry but also in other business areas where cost pressure is high. The need to drive cost down means that every cent spent on recurring engineering costs needs to be justified. A conflict between functional requirements (functionality, system reliability, production and manufacturing aspects etc.), testing and maintainability aspects is given. Software reprogramming, as a key issue within the automotive industry, solve that given conflict partly in the past. Software Reprogramming for in-field service and maintenance in the after sales markets provides a strong method to fix previously not identified software errors. But the increasing software sizes and therefore the increasing software reprogramming times will reduce the benefits. Especially if ECU’s software size growth faster than vehicle’s onboard infrastructure can be adjusted. The thesis result enables cost prediction of embedded systems’ software reprogramming by generating an effective and reliable model for reprogramming time for different existing and new technologies. This model and additional research results contribute to a timeline for short term, mid term and long term solutions which will solve the currently given problems as well as future challenges, especially for the automotive industry but also for all other business areas where cost pressure is high and software reprogramming is a key issue during products life cycle

Mini Actuators for Safety Critical Unmanned Aerial Vehicles Avionics

The present article details the development steps and experimental results obtained during the development of smart actuators used on mini unmanned aerial vehicles (UAV). The research effort is driven by the need of developing onboard health monitoring and diagnostics units for small size UAVs to improve their reliability. In the present all small UAVs use single string avionics systems with no built in redundancy, moreover the servo actuators onboard the airplane are often commercial off the shelf (COTS) hobby components with no reliability figures, limited performance guarantees and one directional communication using analog PWM signals. The development of new servo generation focused on solving the above issues. The proposed servo actuators use the existing mechanical gearboxes and housing of the COTS components, but their power electronics, motor control hardware and software components, sensors are custom designed to fit the needs of a higher demand. The actuators with their controlling microprocessors are capable of establishing two way communication via CAN and FlexRay protocol, suitable for safety critical applications, and self diagnostics features are also hosted onboard the actuators. The development challenges and experimental results in a hardware-in-the-loop (HIL) simulator are discussed in the paper

Fault Tolerant Services for Safe In-Car Embedded Systems

http://www.taylorandfrancis.com/Due to the increasing criticality of the functions in terms of safety, embedded automotive systems must now respect stringent dependability constraints despite the faults that may occur in a very harsh environment. In a context where critical functions are distributed over the network, the communication system plays a major role. First, we discuss the main services and functionalities that a communication system should offer for easying the design of fault-tolerant applications in the automotive context. Then, we review the features of the protocols that are currently considered for being used and, finally, we highlight areas where developments are still needed