Chapter nine

These tutorials are 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:

Core skills are things such as:

1. Why would I create such a feedback loop?

2. How do such closed-loop system behave?

3. Are there generic analysis tools for assessing the behaviour?

4. Are there generic design tools for ensuring the behaviour meets specifications?

The tutorials are a combination of PDF files, with brief worked solutions and video talk through tutorials showing detailed problem solving procedures.

Feedback concepts and introduction

Defining closed-loop transfer functions and links between compensator parameters and closed-loop behaviour.

• Introductory questions

• Introductory questions continued

• Closed-loop stability

Feedback concepts and introduction

Video tutorials with worked solutions to reinforce concepts from tutorials above.

• Video tutorial - impact on first order systems

• Video tutorial - impact on second order systems

• Video tutorial - impact on high order systems

Closed-gain and offset

Several of the gain questions overlaps with the similar section in modelling.

• Introductory questions on gain and offset (PDF, 627KB)

• Offset and advanced scenarios (PDF, 595KB)

Closed-gain and offset

Video tutorials with worked solutions to reinforce concepts from tutorials above.

• Video tutorial on steady-state signals

• Video tutorial on closed-loop offsets

• Video tutorial on offsets with input/output disturbances

• Video tutorial on offsets to ramps

Block diagrams

Students should handle small variations on how blocks/signals are connected in a feedback loop.

• Simple block diagram questions (PDF, 632KB)

• Video tutorial on basic concepts

• Video tutorial on multi-input systems

• Video tutorial on nested loops

Heuristic PI design

Videos giving some worked examples in a tutorial fashion of PI analysis and design.

• Video comparing different PI designs – first order examples.

• Video comparing different PI designs – second order examples.

• Video on iterative design – Note: there is a minor typo in cruise control closed loop model – should be 0.5/(s+0.5).

Longer questions

More representative of exam style questions with multi-step requirements and re-emphasising the potential of MATLAB for checking work and incorporating PI design.

• Exam style questions (PDF, 712KB)

• Use of MATLAB (PDF, 405KB)