Output matrix wrong dimensions

Hi,

I am experimenting with the vehicle steering jupyter example. I noticed the following:

In subsection “Linearization of lateral steering dynamics (Example 6.13)”: # Compute the linearization at velocity 10 m/sec lateral_linearized = ct.linearize(lateral, [0, 0], [0], params=vehicle_params)

When I checked the output matrix of the linearized system, i.e, lateral_linearized.C, it is a 2x2 matrix. This is contradicting with the book & and the explanation on this page. It should rather be a 1x2 matrix with C = np.array([[1, 0]]). I am wondering the source of this inconsistency.

Additionally, a minor fix: The comment should be modified to 15/msec, since this is the given parameter of the vehicle in the code.

Thanks

[bnavigator]

Okay, I see it now. Remove the ‘theta’ from outputs, which does not make sense, because vehicle_output()[1:] only returns ‘y’.

lateral = ct.NonlinearIOSystem(
    lambda t, x, u, params: vehicle_update(
        t, [0., x[0], x[1]], [params.get('velocity', 1), u[0]], params)[1:],
    lambda t, x, u, params: vehicle_output(
        t, [0., x[0], x[1]], [params.get('velocity', 1), u[0]], params)[1:],
    states=2, name='lateral', inputs=('phi'), outputs=('y')
)

This also obsoletes the 0 row index later in the block:

# Set the output to be the normalized state x1/b
lateral_normalized = lateral_transformed * (1/b)

[bnavigator]

I would say leave it open until this will by fixed by changes in the notebook and control.iosys. I might contribute a PR later.