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Fix warnings in DC Motor PI tutorial #411

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merged 2 commits into from
Oct 5, 2025
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Fix warnings in DC Motor PI tutorial #411

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6928f51
Fix warnings in DC Motor PI tutorial
ChrisRackauckas Sep 19, 2025
6da4fa9
Update dc_motor_pi.md
ChrisRackauckas Oct 5, 2025
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17 changes: 13 additions & 4 deletions docs/src/tutorials/dc_motor_pi.md
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Original file line number Diff line number Diff line change
Expand Up @@ -77,7 +77,14 @@ so that it can be represented as a system of `ODEs` (ordinary differential equat

```@example dc_motor_pi
sys = mtkcompile(model)
prob = ODEProblem(sys, [sys.L1.i => 0.0], (0, 6.0))
# Provide complete initial conditions for all state variables
u0 = Dict(
sys.L1.i => 0.0, # Initial inductor current
sys.inertia.w => 0.0, # Initial angular velocity
sys.inertia.phi => 0.0, # Initial angle
sys.pi_controller.int.x => 0.0 # Initial PI integrator state
)
prob = ODEProblem(sys, u0, (0, 6.0))
sol = solve(prob)

p1 = plot(sol.t, sol[sys.inertia.w], ylabel = "Angular Vel. in rad/s",
Expand Down Expand Up @@ -107,12 +114,14 @@ T(s) &= \dfrac{P(s)C(s)}{I + P(s)C(s)}

```@example dc_motor_pi
using ControlSystemsBase
# Get sensitivity function
matrices_S,
simplified_sys = Blocks.get_sensitivity(
simplified_sys_S = Blocks.get_sensitivity(
model, :y, op = Dict(unknowns(sys) .=> 0.0))
So = ss(matrices_S...) |> minreal # The output-sensitivity function as a StateSpace system
# Get complementary sensitivity function
matrices_T,
simplified_sys = Blocks.get_comp_sensitivity(
simplified_sys_T = Blocks.get_comp_sensitivity(
model, :y, op = Dict(unknowns(sys) .=> 0.0))
To = ss(matrices_T...)# The output complementary sensitivity function as a StateSpace system
bodeplot([So, To], label = ["S" "T"], plot_title = "Sensitivity functions",
Expand All @@ -123,7 +132,7 @@ Similarly, we may compute the loop-transfer function and plot its Nyquist curve

```@example dc_motor_pi
matrices_L,
simplified_sys = Blocks.get_looptransfer(
simplified_sys_L = Blocks.get_looptransfer(
model, :y, op = Dict(unknowns(sys) .=> 0.0))
L = -ss(matrices_L...) # The loop-transfer function as a StateSpace system. The negative sign is to negate the built-in negative feedback
Ms, ωMs = hinfnorm(So) # Compute the peak of the sensitivity function to draw a circle in the Nyquist plot
Expand Down
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