Resource-aware fault accommodation in spatially-distributed processes with sampled-data networked control systems

Abstract

This paper addresses the problem of fault-tolerant stabilization of spatially-distributed systems with uncertain low-order dynamics, sensor-controller communication constraints, discretely-sampled state measurements and control actuator faults. An approximate finite-dimensional model that describes the dominant dynamics of the infinite-dimensional system is initially used to design a model-based event-triggered networked control system with a well-characterized stability-based communication-triggering threshold under the assumption that state measurements are continuously sampled. A modification of the communication threshold that takes into account the system's limited ability to monitor the state under discrete measurement sampling is then developed. Based on a forecast of the evolution of the model estimation error, an upper bound on the error growth over each sampling interval is obtained and to derive a tighter communication trigger that is used for sampled-data implementation. The modified threshold is explicitly characterized in terms of the fault magnitude, the model and controller design parameters, and the control actuator locations. Based on this characterization, resource-aware fault accommodation strategies are devised to achieve the desired balance between the fault-tolerant stabilization and reduced network utilization objectives. Finally, the results are illustrated using a diffusion-reaction process example.