In a previous post we discussed how the principles of operation of a balance scale could be understood as a feedback loop with integral action. We left off after analyzing the impact of measurement disturbances in the loop and mentioned that input disturbances could be used to model “operator errors.”

Continue reading “Balance scales and integral action. Part II”# Tag: disturbance

## Let your inputs go!

As one learns more about feedback and control systems, at some point, comes an important realization that a variety of distinct problems can be answered if we know how to answer the question: “is some closed-loop system asymptotically stable?” Indeed, the study of stability dominates Chapters 6 and 7, arguably the densest chapters in the book. Many students, when asked what they remember from their undergraduate control class, will quickly point at the *root-locus* or at the *Nyquist stability criterion*. Yet, in the beginning, it might seem that stability is a side dish and not the main attraction.

## To disturb or not to disturb?

So here is a recurrent question. You have some model that has a constant showing up on the differential equation and you’re not sure how to handle it. For example, your model looks like:

$$\dot{y}(t)=ay(t)+bu(t)+c$$

where $c$ is a constant. There are multiple ways you can handle this situation.

Continue reading “To disturb or not to disturb?”