Uncertainties and output feedback in rollout event-triggered control

TL;DR

This paper develops robust rollout event-triggered control strategies for networked control systems with output measurements and uncertainties, ensuring constraint satisfaction and convergence while managing traffic.

Contribution

It introduces three robust output feedback strategies for rollout ETC in uncertain NCSs, integrating robust tube-based MPC to handle uncertainties and constraints.

Findings

Strategies ensure recursive feasibility and robust constraint satisfaction.

The methods demonstrate convergence in uncertain output feedback scenarios.

Numerical example validates the effectiveness of proposed approaches.

Abstract

The fact that event-triggered control (ETC) often exhibits an improved performance-communication tradeoff over time-triggered control renders it especially useful for Networked Control Systems (NCSs). However, it has proven difficult to characterize the traffic produced by ETC a priori. Rollout ETC addresses this issue by using a triggering and control law that is implicitly defined by the solution to an optimal control problem (OCP), instead of an explicit one as in classical ETC. This allows to directly incorporate predefined constraints on the transmission traffic as well as on states and inputs. In this article, we examine the practically relevant case when output instead of state measurements are available, and measurements as well as the LTI plant are subject to uncertainties. To address these challenges, we adapt methods from robust tube-based model predictive control and propose three different strategies to implement an error feedback in an NCSs setup, the applicability of which depends on the capabilities of the actuator. We establish recursive feasibility, robust constraint satisfaction and convergence. Finally, we illustrate our results in a numerical example.