Input-Output Stability

In this chapter we will discuss the input-output stability of time-delay systems. The main purpose of presenting this formulation is to consider the stability problem of systems under dynamical uncertainty. The input-output stability framework discussed in this chapter is similar in flavor to Chapter 3. A system is often written in the form of a nominal system and an uncertain feedback, and stability is concluded based on a small gain argument. However, the formulation here is more general. For example, the nominal system may be a time-delay system, and the feedback may be a more general uncertainty which is not necessarily due to time-delay elements.