SIMULINK and GUIs - A Guide to MATLAB for Beginners and Experienced Users - page 123

Figure8-3: TheContinuousLibrary.

by double-clicking on the third icon from the left in Figure 8-1, or in Windows
either by clicking on the to the left of the “Continuous” icon at the top
right of Figure 8-2, or else by clicking on the small icon to the left of the
word “Continuous” in the left panel of the SIMULINK Library Browser. When
opened, the “Continuous” library looks like Figure 8-3.
Noticethat u and u areobtainedfrom u and u (respectively)byintegrating.
Therefore, drag two copies of the Integrator block into the model window, and
line them up with the mouse. Relabel them (by positioning the mouse at the
end of the text under the block, hitting the BACKSPACE key a few times to erase
what you don't want, and typing something new in its place) to read u and u .
Note that each Integrator block has an input port and an output port. Align
the output port of the u Integrator with the input port of the u Integrator
and join them with an arrow, using the left button on the mouse. Your model
window should now look like this:

1
s
u '

1
s
u

This models the fact that u is obtained by integration from u . Now the
differential equation can be rewritten u =− (5 u + 2 u ), and u is obtained
by integration from u . So we want to add other blocks to implement these
relationships. For this purpose we add three Gain blocks, which implement