Pattern Guided Integrated Scheduling and Routing in Multi-Hop Control Networks

Abstract

Executing a set of control loops over a shared multi-hop (wireless) control network (MCN) requires careful co-scheduling of the control tasks and the routing of sensory/actuation messages over the MCN. In this work, we establish pattern guided aperiodic execution of control loops as a resource-aware alternative to traditional fully periodic executions of a set of embedded control loops sharing a computation and the communication infrastructure. We provide a satisfiability modulo theory–based co-design framework that synthesizes loop execution patterns having optimized control cost as the underlying scheduling scheme together with the associated routing solution over the MCN. The routing solution implements the timed movement of the sensory/actuation messages of the control loops, generated according to those loop execution patterns. From the given settling time requirement of the control loops, we compute a control theoretically sound model using matrix inequalities, which gives an upper bound to the number of loop drops within the finite length loop execution pattern. Next, we show how the proposed framework can be useful for evaluating the fault tolerance of a resource-constrained shared MCN subject to communication link failure.