A Distributed Diagnosis Approach to Fault Tolerant Multi-rate Real-Time Embedded Systems

Advanced safety-critical control applications such as fly-by- wire and steer-by-wire are being realized as distributed systems comprising many embedded processors, sensors, and actuators interconnected via a communication medium. They have severe cost constraints but demand a high level of safety and performance. Recently, the authors in paper (Kandasamy et al., 2005) have developed a diagnosis approach for single rate steer-by-wire system. Motivated by the need for timely diagnosis of faulty actuators and processors in multi-rate fly-by-wire systems, we present a general method to implement failure diagnosis under deadline and resource constraints. The proposed method has been compared with the approach given in (Kandasamy et al., 2005). The diagnostic tasks are executed concurrently with control tasks so that actuators and system processors are diagnosed in a distributed fashion to reach an agreement over fault-free units thereby isolating the faulty units. The simulation results are presented evaluating the effectiveness of the proposed method under various design constraints.