Robust filtered Smith predictor for processes with time-varying delay: A simplified stability approach

摘要

This paper presents a family of simplified stability conditions for the filtered Smith predictor control of uncertain systems with time-varying delay. The delay can vary arbitrarily, but its maximum value is assumed to be bounded. Simple design rules are proposed to ensure robust stability in the presence of time-varying delay and model uncertainty. Frequency analysis and design methods can be directly used. Moreover, if (i) the process is open-loop stable and (ii) the closed-loop system without time-varying delay is stable for a given filtered Smith predictor controller, then the robustness filter can always be re-designed to recover robust stability in the presence of any bounded time-varying delay. It is shown that the main results can be extended to multivariable systems. Simulation examples and an experimental case study are presented to illustrate the benefits of the proposed stability conditions and design rules. (c) 2020 European Control Association. Published by Elsevier Ltd. All rights reserved.