Successful Development of High-Confidence Architecture

April 29, 2004

The nextTTA project, intended to develop the next level of Time-Triggered Architecture (TTA), has been completed successfully. The two-year, EC-subsidized project proved that event-triggered communication such as industry standard CAN can be combined with TTA to provide an easy migration path from current CAN-based applications to time-triggered systems. Smart centralized bus guardians were used to enhance dependability and to reduce system cost. A line driver prototype chip with a bandwidth of 10 Mbit/s for in-car use was developed to fulfill the request for higher data throughput. Additionally, an autonomous steering function was set up as a sample application and was integrated into an Audi S8 prototype car.

One of the main reasons for the nextTTA project was to demonstrate the feasibility of event-triggered communication on top of the time-triggered communication service of TTA. Prototype implementations of CAN and TCP/IP protocol emulations were realized with this approach. CAN is an event-triggered communication protocol with excellent performance characteristics that is widely used in automotive communication systems. An emulator was developed in order to run such CAN-based applications in a time-triggered network. With an additional software layer, much legacy software could run unchanged in a time-triggered network.

Time-triggered systems need to fulfill a number of fundamental requirements, including high dependability and more bandwidth. During the nextTTA project, a new line driver prototype chip with a bandwidth of 10 Mbit/s was specified and designed for in-vehicle use. Additionally, the structure, functionality and dependability of TTA were significantly enhanced by smart centralized bus guardians. These devices allow the system to function in an otherwise normal way despite failure of a single node. The use of smart centralized bus guardians reduces cost and fulfills the strict safety requirements of the aerospace industry and other industries that need high levels of dependability.

As part of the nextTTA project, an autonomous steering prototype was developed and integrated into an Audi S8. The steering system was a striking demonstration of the technology’s feasibility and its availability for deployment in commercial automotive production. The prototype car was able to follow the road automatically by receiving data from a video camera that acted as an intelligent sensor. Driving effort was reduced and steering precision was improved. Advanced driver assistance systems with intelligent sensors require both high data throughput and reliable communication. Both of these requirements are addressed by TTA.

TTA is the architecture of choice for high-dependability distributed systems in a variety of application domains. It is a major technological achievement in the area of distributed real-time systems and has attracted a significant amount of attention in a broad range of applications, including aerospace, automotive, special vehicles, railway, and industrial control. Technology leaders such as Airbus, Alcatel, Audi, Honeywell, UTC’s Nord-Micro, and others are actively working with TTA. In a substantial number of cases, the technology is already in commercial production.

About nextTTA Project
The nextTTA project was subsidized by the European Commission. Various research institutions and companies participated as project partners. austriamicrosystems AG, Audi AG, Budapest University of Technology and Economics, TTTech Computertechnik AG, University of Ulm, University of York, Vienna University of Technology, Université Joseph Fourier, Centre National de la Recherche Scientifique, Institut National Polytechnique de Grenoble, and Technische Universität Darmstadt contributed to the successful completion of nextTTA. SRI International took part in the nextTTA project as a sub-partner.

For further information on nextTTA please visit the following website: