On multiple-delay output feedback stabilization of LTI plants

Control systems subject to delays have been extensively studied (see, e.g. the textbook [1]). Recently, several researchers have sought to design controllers that usemultiple delayed observations, with the motivation that properly designed delays can in some special cases act to stabilize a system [2–4]. Fundamentally, these multiple-delay controllers are constructed by first designing controllers that use derivatives of the output, and then approximating these derivatives using delaydifferences. Specifically, Niculescu and coworkers have addressed multiple-delay pole-placement controller