A robust controller is developed for uncertain, second-order nonlinear systems subject to simultaneous unknown, time-varying state delays and known, time-varying input delays in addition to additive, sufficiently smooth disturbances. An integral term composed of previous control values facilitates a delay-free open-loop error system and the development of the feedback control structure. A stability analysis based on Lyapunov-Krasovskii (LK) functionals guarantees uniformly ultimately bounded tracking under the assumption that the delays are bounded and slowly varying.
@article{arxiv.1501.03810,
title = {Time-Varying Input and State Delay Compensation for Uncertain Nonlinear Systems},
author = {Rushikesh Kamalapurkar and Nicholas Fischer and Serhat Obuz and Warren E. Dixon},
journal= {arXiv preprint arXiv:1501.03810},
year = {2017}
}