Resource aware quasi-decentralized control of networked process systems over wireless sensor networks

This paper develops an integrated model-based networked control and scheduling framework for plants with interconnected units and distributed control systems that exchange information using a resource-constrained wireless sensor network (WSN). The framework aims to enforce closed-loop stability while simultaneously minimizing the rate at which each node in the WSN must collect and transmit measurements. Initially, the exchange of information between the local control systems is reduced by embedding, within each control system, dynamic models that provide forecasts of the evolution of the plant units when measurements are not transmitted through the WSN, and updating the state of each model when communication is re-established at discrete time instances. To further reduce WSN utilization, only a subset of the deployed sensor suites are allowed to transmit their data at any given time to provide updates to their target models according to a certain scheduling strategy. By formulating the networked closed-loop plant as a combined discrete-continuous system, explicit characterizations of both the stability and performance properties of the networked closed-loop system under state and output feedback control are obtained in terms of the communication rate, the sensor transmission schedule, the accuracy of the models, as well as the controller and observer design parameters. The results are illustrated using a chemical plant example where it is shown that by judicious management of the interplays between the control, communication and scheduling design parameters, it is possible to enhance the savings in WSN resource utilization beyond what is possible with concurrent transmission configurations.

► A novel method for quasi-decentralized control of chemical plants over networks.
► Model-based control is a viable approach for conserving limited network resources.
► Sensor scheduling enhances the plant's robustness to communication disruptions.
► Rigorous analysis of the plant's stability and performance properties.
► Application via computer simulations to a cascade of chemical reactors with recycle.