MATLAB: Is there a way to save gain/damping/overshoot data from a root locus plot.

Control System Toolboxdampingdatafigurefrequencygainovershootratioroot locussave

So my problem is this – when I use the rlocus() command to generate a root locus plot, I can use the data cursor on the figure to see the value of damping/overshoot/frequency/gain for a given pole position. However, when I save the figure and re-open it all this data disappears and I can no longer do this. Is there a way to save root locus figure so that for example, if I was to open it on a version of Matlab without the control systems toolbox I could instantly see these parameters?

Best Answer

Currently this can not currently be done. I have created an ehancement request to consider this. You could however compute the damping/overshoot/frequency from the (x,y) coordinates of the pole locations.

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MATLAB: Conversion from State Space to TF and then back to State Space

Some points:

Don't do "algebra" with tf variables, use the functions series, parallel and feedback.

sys_mimo1 = ss(sys_mimo) is going to convert the tf model to a ss model, I don't think there is a need for the extra step with ssdata.

This one here

sys_mimo_tf(1,2) = sys_mimo_tf(1,2)*feedback(sys_mimo_tf(1,2),C);

is probably not doing what you want it to, it will give you the transfer function

sys_mimo_tf(1,2)^2 /  1 + sys_mimo_tf(1,2)*C

so that's probably where many extra states come from. You should expect 2 extra states per added PID.

Lastly, look at the Hankel Singular Values or a similar measure to figure out whether there might be a lot of almost unobservable/almost uncontrollable states in your resulting model. That would indicate numerical issues.

MATLAB: If i have poles and zeros of a transfer function, how to obtain this transfer function ??

transfer_function = tf( zpk(ListOfZeros, ListOfPoles, ListOfGains))

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MATLAB: Conversion from State Space to TF and then back to State Space

MATLAB: If i have poles and zeros of a transfer function, how to obtain this transfer function ??

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