A time-triggered transducer network based on an enhanced IEEE 1451 model

Abstract

The IEEE 1451 set of standards defines an architectural model for interfacing multiple ‘smart transducers’ in a distributed environment, which can gate to a fieldbus or local area network. However, the IEEE 1451 standards do not support strict real-time message scheduling within the transducer cluster environment. This work proposes that a time-triggered control network, TTCAN (time-triggered controller area network), be employed as the multiplexed interface for smart transducers. Such a development would allow a deterministic control message scheduling matrix to be defined so that all transducer message scheduling can be guaranteed. The proposal effectively changes the IEEE 1451 architecture from an event-driven system to a true time-driven system. The existing set of IEEE 1451 standards are briefly reviewed and the new TTCAN control network is described. A complete prototype design implementation of the proposed system is presented. The prototype system demonstrates that the concept is feasible and workable. Time-triggered networks are synchronous control networks where the scheduling of control messages is progressed, based strictly on the passage of time, based on the network's sense of global time. Such time-triggered networks are being developed primarily for the automotive industry to support reliable scheduling for safety-critical control systems such as brake-by-wire and steer-by-wire systems. This work shows that it is now possible to apply such time-triggered paradigms to general transducer interfacing environments.