Kristina Ahlström

Licentiatuppsats som presenteras vid seminarium i
Henry Wallmans rum, vån 6 S, Hörsalsvägen 11, Chalmers
Onsdagen den 6 december 2000, kl.15.15

Diskussionsledare är Dr Jonas Vasell från
CR&T, Göteborg


Future Control-By-Wire systems are anticipated to face increased requirements of flexibility, scalability, low weight, predictability, and testability. This at reduced complexity and maintenance costs. These increased requirements are best met with distributed control systems from a cost efficient point of view.

To investigate how a future control-by-wire system could be designed, if distributed control and smart actuators and sensors are used, a study of a flight control system is carried out. This thesis presents a design methodology and results in a proposed future distributed architecture.

Various issues regarding distributed architectures are investigated, including system operation, control and computing allocation between nodes, communication requirements, physical distribution, hardware redundancy, communication scheduling and fault handling. Based on these findings, a robust fault tolerant distributed architecture with minimum hardware and low bandwidth is proposed.

The communication in a distributed system is the most vital component with high reliable demands. An electrical bus system is the cheapest and most reliable communication network available in the near future for fly- and drive-by-wire systems. Theoretical and experimental investigations of achievable bandwidth, including adequate EMC qualities, with an electrical bus are also part of this thesis work.

Keywords: Distributed control, distributed systems, design methodology, embedded systems, real-time communication, and safety critical control systems.