Integral action controllers for systems with time delays

Abstract

Consider a stabilizing controller C 1 for a given plant P. If C 1 and P do not have any zeros at the origin, then one can use a cascade connected PI (proportional plus integral) controller C pi with C 1 and keep the feedback system stable. In this work we examine the allowable range of the integral action gain in C pi , and discuss how C 1 should be chosen to maximize this range for systems with time delays.