Analysis and Accommodation of Communication Failures in Event-Triggered Networked Distributed Control Systems

This work presents an approach for the analysis and accommodation of sensor-controller communication failures in spatially-distributed processes controlled over a resource-constrained communication medium. We focus on distributed processes whose dominant dynamics are finite dimensional, but uncertain, with a finite number of spatially distributed networked control actuators and measurement sensors. Initially, a model-based networked output-feedback controller is designed based on an approximate low-order model that captures the slow dynamics of the infinite-dimensional system. The controller is implemented using an event-triggered sensor-controller communication policy, which determines the times when the sensor data need to be transmitted to the controller to update the model state based on a suitably designed stability threshold. An assessment of the networked control systems robustness to failures in the communication medium is carried out using an online forecasting approach that tracks the growth of the estimation errors during times of communication outages. An explicit characterization of the allowable down time that communication losses can be tolerated without compromising closed-loop stability is obtained in terms of the various control system design parameters, and used to devise various accommodation measures that enhance the networked closed-loop systems robustness against communication losses. A simulated diffusion-reaction process example is used to illustrate the developed approach.