Asynchronous Sampling for Decentralized Periodic Event-Triggered Control

Decentralized periodic event-triggered control (DPETC) strategies are an attractive solution for wireless cyber-physical systems where resources such as network bandwidth and sensor power are scarce. This is because these strategies have the advantage of preventing unnecessary data transmissions and therefore reduce bandwidth and energy requirements, however the sensor sampling regime remains synchronous. Typically the action of sampling leads almost immediately to a transmission on an event being detected. If the sampling is synchronous, multiple transmission requests may be raised at the same time which further leads to bursty traffic patterns. Bursty traffic patterns are critical to the DPETC systems performance as the probability of collisions and the amount of requested bandwidth resources become high ultimately causing delays. In this paper, we propose an asynchronous sampling scheme for DPETC. The scheme ensures that at each sampling time, no more than one transmission request can be generated which prevents the occurrence of network traffic collision. At the same time, for the DPETC system with asynchronous sampling a pre-designed global exponential stability and £2-gain performance can still be guaranteed. We illustrate the effectiveness of the approach through a numerical example.