Robust performance case study (Matlab) 3: scaled small gain and h-infinity optimization (approx. musyn)

Antonio Sala, UPV

Difficulty: ***** ,       Relevance: ,      Duration: 13:31

*Enlace a Spanish version

Summary:

This video is the last in the case study started in video [cerp1EN] and continued in video [cerp2EN].

Robust performance bounds for a hand-tuned PID were proved in the referred videos. In here, we replace the PID by an hinfsyn controller. This allows us to both increase the modelling error bound and increase the closed-loop bandwidth. Scaled small gain is needed, playing with the multiplier $S$ so a closed-loop infinity norm bound of 1 is achieved.

Of course, the procedure in this video is crudely simplistic, merely illustrative: a better-tuned PID might have achieved comparable performance, the plant cancellation by the h-infinity controller may result in bad input disturbance performance, and the manual search of the multiplier can be replaced by iterative-convex-optimization steps, as done by the command musyn, which actually is “the way to go”, explored in other videos of this collection... in particular [cerp4muEN] and [cerp5muEN].

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