Distributed Fault-Tolerant and Safety-Critical Applications in Vehicles - A Time-Triggered Approach

For various reasons complex safety related functions in future automotive systems will be based on electronics without relying on mechanical or hydraulic back-up. Benefits of these so-called “X-By-Wire”-systems are simplified packaging, an increase of active and passive safety, the easy integration of driver assistance systems and the absence of hydraulic fluids. The objective of the Brite EuRam III Project “Safety Related Fault Tolerant Systems in Vehicles (X-By-Wire)” is to develop a framework for an electric/electronic architecture for X-By-Wire systems. For safety reasons these systems must be distributed, fault-tolerant and connected by a fault-tolerant real time communication medium. The time triggered protocol TTP/C satisfies the communication requirements. This protocol operates on a duplicated bus, it sends actively replicated messages and provides error detection in the domains of time and value as well as a globally synchronized time base. Within the X By-Wire project a prototype of a steer-by-wire system is assembled. This prototype will demonstrate the application of the general ideas, the principles, and the mechanisms developed by the X-By-Wire partners.