This video shows how margin can be used to assess the robustness of multi-input, multi-output systems. We’ll show how disk margin is a more complete way to represent margin for MIMO systems over classical gain and phase margin.

We’re going to approach this topic in three parts. In the first part, we’ll set up a two-input, two-output plant, and describe it in some detail so that you have a little intuition behind it. In part two, we’ll develop a very simple controller that can successfully track two independent set points. And in part three, we’ll check how robust our controlled system is to variations.