I have a school project where I would like to use Simulink to model and tune my system. I have a relatively simple system that consists of two feedback loops, each with a gain. I'm using this tutorial
to do the basic tuning, and I understand the basics. But for my system, I would like to tune both gains individually and be able to look at the root locus of the inner loop and the root locus of the outer loop simultaneously. Choosing the gains to be tuned is easy enough, but when I select the two root loci, they are both 5th order. The inner loop is only 3rd order and the outer loop is 5th order, so I would expect my root loci to reflect that. At this point, I don't know what the two loci represent since they are both of the 5th order.
Anyway, I hope I have given an adequate description of my problem, but I will gladly provide any more detail as necessary. I didn't want to bog down the question with unneeded specifics, but I'm not sure what may be relevant, so please ask for any needed clarifications.
Thanks for reading my question and for any help you can offer.
My guess about why you are getting 5th order system for inner loop is that you did not specify loop opening properly to break the outer loop, when defining the inner loop.
Please take a look at this example, where the issue is explained in detail. You should be able to follow this example and use root locus plots instead of bode plots that are used in the example.
Hope this helps.