How should I draw the root locus of a system with this open loop transfer function in MATLAB: exp(-.1s)/(s*(s+6))
Its root locus is supposed to have many branches. Am I right?
The problem is the dealy. If the system didn't have any dealy, I would draw its root locus by this command:
rlocus([1],[1 6 0])
Please help me.
Thanks in advance; Zeinab Ghofrani
One option
look up pade approximation for an approximate rational approximation to the timedelay
Which will work for a small delay. Your other two choices are to (a) write a script to find the roots and plot them, or (b) transform the thing into the z domain with a "sampling" time of 10Hz, do the root locus there, then translate all of the traces back into the time domain. The second option is better in my opinion, because it tells you the one gain where you go out of stability.
On Sun, 11 Jul 2004 4:43:09 +0100, Zeinab Ghofrani wrote (in message ):
Download ROOTLOCS from:
It plots root loci of systems with up to 20 poles and 20 zeros, including systems with pure time delay in the loop. Its available in versions for Mac and PC.
Yes, systems with time delay exhibit an infinite number of locus branches.
AAR
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