The force is supposed to be applied only when the roll angle is +/- 15 degrees.  As shown on the cosine plot below, the only place where the output of the cosine function is greater than or equal to .9659 is between +/- 15 degrees.

We will model this by feeding the roll angle into a cosine element. The output of the cosine will then be feed into a lookup table which will then output a pulse train.

1. Select the Cosine icon
2. Mouse click the spot on the diagram for the table. To keep consistant with our pictures, you can choose the third column in the sixth row.
3. Select the lookup table icon
4. Mouse click the spot on the diagram for the table. To keep consistant with our pictures, you can choose the fourth column in the sixth row.
5. Connect Phi to the cosine element by choosing the connector icon and then clicking Phi and then the cosine element.

6. Ditto connect the cosine to the lookup element
7. Click on the lookup table that you just placed
8. Set the properties of the lookup table to have 3 rows. 
9. Input the table values as shown below

Any time that the cosine of the roll angle is greater than .9659 the roll angle is between +/- 15 degrees

Your block diagram should look similar to the diagram below

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