Adaptive Control of Linear Systems with Variable Time Delay

Abstract

This paper presents an algorithm for adaptive control of linear systems having unknown time delay. A rational approximation is used for the delay and it is argued that within this framework, the analysis of the properties of the corresponding adaptive control algorithm essentially reduces to the issue of robustness to unmodelled dynamics. A global convergence theory is presented using recent methods for analyzing robustness properties of adaptive control algorithms. It is argued in the paper that a rational approximation gives a highly accurate and effective way of dealing with variable time delays. The analysis is supported by simulation results.