Equilibrium Sampling Interval Sequences for Event-driven Controllers

Standard discrete-time control laws consider periodic execution of control jobs. Although this assumption simplifies the control design and the resource utilization analysis for later implementation, it leads to a conservative usage of computing resources. On the contrary, event-driven control offers controllers with a tighter resource utilization. However, job executions are no longer periodic, and predicting their computing requirements is crucial for efficient implementation in severely limited computing systems. Sampling intervals for event-driven control systems show different patterns, ranging from chaotic behaviors to periodic oscillatory patterns, named equilibrium sampling interval sequences (ESIS). Focusing on resource demands predictability, in this paper we identify the conditions for event-driven controllers to exhibit ESIS, and provide methods to characterize and compute them. Finally, we study the transitions from ESIS to chaotic sampling. Simulated experiments illustrate the paper contributions.