As we discussed in the last video, mathematical models aren’t a perfect representation of real systems. Therefore, we want to make sure that any system that is designed with those models is robust to the expected variations of the real system. Margin is a way to specify how much uncertainty your system can handle before it no longer meets the requirement.
This video explains what disk margin is, why it might be a better representation of how much margin your system has over something like classical gain and phase margins, and how to interpret the results.