MATLAB Answers

margin command on a system with transfer function on reference

1 view (last 30 days)
I have the following system (see picture). When calculating gain and phase margins with 'margin' command, should I consider L=GK to be an open loop transfer function (i.e. should I call margin(GK) )? If so, what difference does the transfer function H applied on the reference r make to gain and phase margins?

Accepted Answer

Sriram Narayanan
Sriram Narayanan on 13 Aug 2015
It depends on what you are using the Transfer Function H for. H would typically be used as a prefilter or for feedforward control. So, it should not be shaping the crossover frequency and therefore, would not have an effect on the gain/phase margins. However, you should calculate gain/phase margins using the open-loop GK to meet desired robustness/disturbance rejection requirement and the prefilter H could help is adjusting the reference to meet reference tracking requirement.

More Answers (0)

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!