Compensator design methods

Module overview. Analytical design methods are of interest when the plant model is given as a transfer function and the plant parameters are known. Whereas the pole zero compensator systematic design procedures are indirect methods based on performance indices and their graphical interpretation occur in Bode diagrams, the compensator designs given here are direct methods based on a given transfer function for the closed loop. First, an introduction into the specifications of closed-loop transfer functions is given, then the method of Truxal and Guillemin including different examples of stable, unstable and non-minimum phase plants is shown. This method is the basis of a generalised compensator design procedure that can cope simultaneously both with disturbances and command changes, where the disturbance can occur at different locations. A comprehensive example demonstrates the application.

Module objectives. When you have completed this module you should be able to:

1. Use standard forms to specify the closed-loop behaviour.
2. Design compensator controllers for stable, unstable and non-minimum phase plants.
3. Cope with disturbances for compensator-based control systems.

Module prerequisites. Transfer function, performance indices.