In the Step Tracking Goal dialog, specify the reference signals for tracking. Under
Specify step-response inputs, click Add signal to list. Then click Select signal from
model.
In the Simulink model editor, select the reference signals theta_ref, phi_ref, and
r_ref. These signals appear in the Select signals dialog box. Click Add Signal(s) to add
them to the step tracking goal.
Next, specify the outputs that you want to track those references. Under Specify step-
response outputs, add the outputs theta, phi, and r.
The requirement is that the responses at the outputs track the reference commands with
a first-order response that has a one-second time constant. Enter these values in the
Tune a Control System Using Control System Tuner