Find Transfer Function of System for Root Locus Plot?


Joined Mar 6, 2009
Since one can only create a root locus for a single gain term you cannot investigate the inner and outer loop stability issues simultaneously. I would imagine one would set up a sequence of root loci in which the outer loop gain K1 is varied continuously whilst K2 is varied in steps over a range of sensible (stable?) values. So one obtains a series of root loci in which K1 is the primary variable with K2 fixed but different for each locus drawn. For each specific K2 value the inner loop would be replaced by the equivalent transfer function resulting from the inner loop being closed at that K2 value.
It will not be a trivial task.
I'm not sure if it has been mentioned before, but with your threads spread far and wide it's difficult to keep track of who said what - Are you familiar with the text "Automatic Control of Aircraft and Missiles" by John Blakelock? It gives many examples possibly relevant to your case.
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