Co-modelling of faults and fault tolerance mechanisms

Abstract

Design for dependability is essential for the increasing range of embedded systems with rich digital control. However, the need to model and mitigate faults on the part of the system, user or environment, can introduce complexity into design. We present approaches to the description of realistic and faulty behaviour, as well as fault-tolerance mechanisms, in co-models of embedded systems. We demonstrate how established techniques including HAZOP studies and FMEA can be integrated with embedded systems design that uses co-models linking discrete-event descriptions of computing elements with continuous-time descriptions of controlled plant. The approaches are illustrated using two case studies.