An Online Bandwidth Scheduling Algorithm for Distributed Control Systems with Multirate Control Loops

In this paper, we present an online scheduling algorithm for communication in a distributed control system. The packet size of the communication varies for each execution of the loop within certain bounds. We consider systems with closed loops that restart immediately after the completion of an execution. Our algorithm is based on priority of the loop and size of the communication packet. We demonstrate through simulation that our algorithm generates a feasible schedule that minimizes average control delay over all the loops. Our simulations demonstrate that this online schedule reduces average delay significantly compared to a-priori schedules for distributed control systems. We demonstrate that bandwidth utilization is more efficient in case of online scheduling.