Design method for conceptual design of by-wire control: two case studies

Safety critical mass produced products are today being implemented without mechanical backup. Most of these will have distributed real time computer networks, which mast be ultra-dependable. A development method for future control-by-wire systems is presented. By using a scalable software architecture and the systems' intrinsic redundancy, it is possible to achieve dependability requirements cost-effectively. The method starts with analyzing a functional task-graph, which gives input for developing a non-redundant architecture. The redundant architecture is modified to dependability requirements by adding hardware redundancy. The functionality implemented in software is allocated to the network according to some optimization criteria. The proposed method has been used in two cases; a fly-by-wire aircraft and a drive-by-wire car.