Chapter three

Introduction to feedback

Section five: Dealing with Uncertainty

This chapter is on the theme of linear feedback control, for example with G(s) representing a system, M(s) a compensator and d an input disturbance signal:

This section focuses on managing uncertainty. The world around us is suffused with uncertainty, that is, things we do not know, cannot measure, cannot model or cannot predict. How do we ensure that systems produce the outputs we want, notwithstanding this uncertainty? As befits an introductory course, we avoid formal tools which by and large require substantial and advanced mathematical machinery.

1. Why does handling uncertainty matter?

A number of videos talk through the impact of uncertainty and therefore the importance of feedback within our lives and engineering.

Impact of uncertainty on behaviour video

More illustrations: closed-loop and open-loop video

Quantifying the impact of uncertainty video

2. MATLAB GUI demonstrating the impact of uncertainty on a tank level system

A summary of the GUI and how it works (PDF, 470 KB)

The GUI (a MATLAB m-file) are available here.

A short video demonstration of how to use the GUI

3. MATLAB GUI demonstrating the impact of uncertainty on a heat exchanger system

A summary of the GUI and how it works (PDF, 847 KB)

The GUI (a MATLAB p-file and fig file) are available here (both needed).

A short video demonstration of how to use this GUI