A Reconfiguration-Based Fault-Tolerant Anti-Lock Brake-by-Wire System

Anti-Lock Braking Systems (ABS) and Brake-by-Wire Systems (BBW) are safety-critical applications by nature. Such systems are required to demonstrate high degrees of dependability. Fault-tolerance is the primary means to achieve dependability at runtime and has been an active research area for decades. Fault-tolerance is usually achieved in traditional embedded computing systems through redundancy and voting methods. In such systems, hardware units, actuators, sensors, and communication networks are replicated where special voters vote against faulty units. In addition to traditional hardware and software redundancy, hybrid and reconfiguration-based approaches to fault-tolerance are evolving. In this article, we present a reconfiguration-based fault-tolerant approach to achieve high dependability in ABS BBW braking systems. The proposed architecture makes use of other components of less safety-critical systems to maintain high dependability in the more safety-critical systems. This is achieved by migrating safety-critical software tasks from embedded computer hardware that runs into a malfunction to other embedded computing hardware running less-critical software tasks. Or by using a different configuration in terms of the used speed sensors and type of ABS. The proposed architecture is on average 20% more reliable than conventional ABS architectures assuming equal reliabilities of different components.