Hello guys. I’m having trouble plotting the root locus diagram. He doesn’t show my roots.
X(s) = \frac{6s+204}{s^3+10s^2+34s}
using ControlSystems
sys2 = tf(
[6,204],
[1,10,34,0]
)
rlocusplot(sys2)
The Julia code above draws the following graph:
But the scilab equivalent shows a root close to -35.
How do I show the hidden root?
Try setting the xlim keyword argument.
As @baggepinnen says, try
rlocusplot(sys2, xlims=(-40, 10))
Part of the rlocusplot recipe (in src/root_locus.jl) is the line,
xlims --> (max(-50,minimum(redata) - 1), clamp(maximum(redata) + 1, 1, 50))
This finds the limits of the calculated root positions as the gain K is swept from 1e-6 to 500, but unfortunately this doesn’t include the location of the zero in this case.
Another package to analyse control systems is controlz.jl:
