Output Feedback to Improve the Delay Margin of Linear Delay Systems

In this article, the delay margin problem of linear systems with multiple time delays is investigated. First, estimations for the delay margin of uncontrolled system are provided by the argument principle. Then, in order to achieve wider delay range for robust stability of the control system, an output feedback controller is designed to improve the delay margins. The output feedback gain matrices can be computed by solving the optimization problems with respect to the delay margin. Finally, numerical examples to illustrate the effectiveness of the approach are given in this article.