Passivity and passification of time-delay systems ✩

In this paper, the problems of passivity and passification of a class of linear time-delay systems are investigated. A new state-transformation is developed to exhibit the delay-dependence. It is established that the passivity condition can be cast in a linear matrix inequality (LMI) format. For state feedback passification, it is proven that it is indifferent to use instantaneous or delayed statefeedback. The case of dynamic output feedback passification is also treated. Numerical examples are provided.  2004 Elsevier Inc. All rights reserved.