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doc: updating MTK example to v11 in manual. #340

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44 changes: 16 additions & 28 deletions docs/src/manual/mtk.md
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Original file line number Diff line number Diff line change
Expand Up @@ -23,43 +23,30 @@ the last section.
will work for all corner cases.

!!! compat
The example works on `ModelingToolkit.jl` v10 (corresponding to the following `[compat]`
entry: `ModelingToolkit = "10"`).
The example works on `ModelingToolkit.jl` v11 (corresponding to the following `[compat]`
entry: `ModelingToolkit = "11"`).

We first construct and instantiate the pendulum model:

```@example 1
using ModelPredictiveControl, ModelingToolkit
using ModelingToolkit: D_nounits as D, t_nounits as t, varmap_to_vars
@mtkmodel Pendulum begin
@parameters begin
g = 9.8
L = 0.4
K = 1.2
m = 0.3
end
@variables begin
θ(t) # state
ω(t) # state
τ(t) # input
y(t) # output
end
@equations begin
D(θ) ~ ω
D(ω) ~ -g/L*sin(θ) - K/m*ω + τ/m/L^2
y ~ θ * 180 / π
end
end
@named mtk_model = Pendulum()
mtk_model = complete(mtk_model)
@parameters g=9.8 L=0.4 K=1.2 m=0.3
@variables θ(t)=0 ω(t)=0 τ(t)=0 y(t)
eqs = [
D(θ) ~ ω
D(ω) ~ -g/L*sin(θ) - K/m*ω + τ/m/L^2
y ~ θ * 180 / π
]
@named mtk_model = System(eqs, t)
```

We than convert the MTK model to an [input-output system](https://docs.sciml.ai/ModelingToolkit/stable/basics/InputOutput/):

```@example 1
function generate_f_h(model, inputs, outputs)
(_, f_ip), x_sym, p_sym, io_sys = ModelingToolkit.generate_control_function(
model, inputs, split=false; outputs
model, inputs, split=false, simplify=true
)
if any(ModelingToolkit.is_alg_equation, equations(io_sys))
error("Systems with algebraic equations are not supported")
Expand Down Expand Up @@ -98,10 +85,11 @@ function generate_f_h(model, inputs, outputs)
end
return nothing
end
p = varmap_to_vars(defaults(io_sys), p_sym)
println(bindings(io_sys))
p = varmap_to_vars(bindings(io_sys), p_sym)
return f!, h!, p, x_sym, nu, nx, ny
end
inputs, outputs = [mtk_model.τ], [mtk_model.y]
inputs, outputs = [τ], [y]
f!, h!, p, x_sym, nu, nx, ny = generate_f_h(mtk_model, inputs, outputs)
x_sym
```
Expand All @@ -121,8 +109,8 @@ model = setname!(NonLinModel(f!, h!, Ts, nu, nx, ny; p); u=vu, x=vx, y=vy)
We also instantiate a plant model with a 25 % larger friction coefficient ``K``:

```@example 1
@named mtk_plant = Pendulum(K=1.25*defaults(mtk_model)[mtk_model.K])
mtk_plant = complete(mtk_plant)
plant_bindings = merge(bindings(mtk_model), Dict(K => 1.25 * bindings(mtk_model)[K]))
@named mtk_plant = System(eqs, t, [θ, ω, τ, y], [g, L, K, m]; bindings=plant_bindings)
inputs, outputs = [mtk_plant.τ], [mtk_plant.y]
f2!, h2!, p2 = generate_f_h(mtk_plant, inputs, outputs)
plant = setname!(NonLinModel(f2!, h2!, Ts, nu, nx, ny; p=p2), u=vu, x=vx, y=vy)
Expand Down
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