Real-Time Scheduling of PI Control Tasks

Abstract

Modern control systems are increasingly realized on embedded systems, where the computation resources are limited. This brief addresses the scheduling of a set of control tasks that are implemented on one single processor. For improving the control performance and achieving an efficient utilization of the limited computation resources, an intelligent scheduling algorithm is essential. Therefore, a novel scheduling algorithm with output feedback resource allocation is proposed for scheduling a set of proportional–integral (PI) control tasks. Thereby, an extended PI controller is introduced that can handle time-varying sampling intervals. For deriving an a posteriori stability criterion, each plant with the scheduled PI controller is modeled as a discrete-time switched linear system. The stability criterion is eventually formulated as a linear matrix inequality feasibility problem. The effectiveness of the proposed online scheduling approach is illustrated by simulation and practical implementation.