Definition of a cost-effective, fault-tolerant control architecture : application to the design of a steer-by-wire system

The objective of this thesis is the definition of a cost-effective fault-tolerant architecture for use in safety-critical embedded control systems. Typical practical examples of such systems are the "By-Wire" systems (e.g. Steer-by-Wire, Throttle-by-Wire, etc) which will likely be applied on-board cars and pleasure boats in the not-too-distant future. The novel architecture presented in this thesis performs error detection and error treatment at the sensor, actuator and Electronic Control Unit levels. It is based on the use of triple modular redundancy. A number of software utilities are defined, which interact with an object-oriented model of the physical system and provide redundancy management, multi-level error detection and dynamic software reconfiguration. A stateline architecture is also presented, which allows the system to dynamically isolate faulty nodes from the network and to perform the necessary hardware reconfiguration when a faulty ECU is detected. The methods developed concentrate upon the use of dynamic reconfiguration so as to ensure optimal use of the available resources and provide safe system operation in the presence of faulty components. The software architecture is coded in the ANS Forth programming language. This architecture has been implemented on a laboratory prototype system which represents a marine Steer-by-Wire application. Details of the actual implementation and of the design of the prototype are provided.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat