Why is the margin() function returning NaN?

ufechner7
Mon, 02 Jun 2025 14:08:01 +0000
Modelling & Simulations

I have the following linear state space system for 8 m/s wind:

julia> @time include("mwes/mwe_06.jl")
StateSpace{Continuous, Float64}
A =
 0.0     0.0                  0.217328
 0.0  -142.50000000000003    -0.16245000000000004
 0.0     0.0               -135.5115580754543
B =
     0.0
     0.0
 77363.88168172735
C =
 0.125  0.5  0.000608
D =
 0.0

Continuous-time state-space model

Why does the function margin return NaN`

[ Info: Gain margin: [NaN;;], Phase margin: [Inf;;], Gain crossover frequency: [14.923313891148691;;], Phase crossover frequency: [85.15256672572397;;]
StateSpace{Continuous, Float64}

The bode plot looks like this (this are two plots in one, one for 8 and one for 9 m/s wind)

6 posts - 3 participants