IMC control of a fast process: constant Q

Antonio Sala, UPV

Difficulty: *** ,       Relevance: ,      Duration: 09:21

*Enlace a Spanish version

Summary:

This video discusses IMC control of a “fast” process where its open-loop settling time is already fast enough for a given application, and we don’t wish to speed it up in closed-loop to, for example, avoid unnecessary actuator oversizing.

In this case, the explicit IMC is easy, it is simply a question of proposing Q=1/dcgain(G). When transformed to a conventional regulator (implicit IMC) with $K=Q∕(1-GK)$, it results in a closed-loop integral action controller, as the theory predicts. So, in the event of input and output disturbances and setpoint changes, it exhibits a closed-loop dynamics that achieves zero error with closed-loop poles in the same place as the open-loop ones, which was our ultimate goal.

*Link to my [ whole collection] of videos in English. Link to larger [ Colección completa] in Spanish.