Chapter three
Introduction to feedback
Introduction to feedback
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:
MATLAB tools are are valuable for modelling, simulating and analysing feedback loops. This section gives a brief introduction to the most important tools.
A number of resources are already provided on the main MATLAB resources page and moreover a concise feedback tool summary (PDF, 522 KB).
It is useful to be proficient with MATLAB syntax for handling polynomials, so some extra notes are provided here (PDF, 900 KB).
A MATLAB live script for doing modelling, analysis and PI control of a 1st order system.
MATLAB has a number of built in functions for handling the analysis of systems represented by transfer function objects, so creating these objects is a core skill.
Continuous time transfer functions video and notes (PDF, 918 KB).
Discrete time transfer functions notes (PDF, 708 KB).
Transfer functions with a delay notes (PDF, 655 KB).
A number of built in functions allow simple analysis of feedback-loops and transfer functions.
Closed-loop transfer functions video and notes (PDF, 575 KB).
Step responses (open- or closed-loop) video and notes (PDF, 558 KB).
Overlaying step-response plots (PDF, 687 KB) and code1 (M-file), code2 (M-file).
Closed-loop poles and iterative design notes (PDF, 739 KB).
Demonstrates real time examples of MATLAB use to analyse and design feedback loops.
Responses with arbitrary inputs
Trial and error design: