A First Course in FUZZY and NEURAL CONTROL

4.4. FUZZY CONTROLLER DESIGN 153

1. If position error is NE and velocity is NA, then motor voltage is Negative.


2. If position error is NE and velocity is ZE, then motor voltage is Negative.


3. If position error is NE and velocity is PA, then motor voltage is Negative.


4. If position error is ZE and velocity is NA, then motor voltage is Zero.


5. If position error is ZE and velocity is ZA, then motor voltage is Zero.


6. If position error is ZE and velocity is PA, then motor voltage is Zero.


7. If position error is PE and velocity is NA, then motor voltage is Positive.


8. If position error is PE and velocity is ZA, then motor voltage is Positive.


9. If position error is PE and velocity is PA, then motor voltage is Positive.

The control surface can be developed usingMatlab,asshowninFigure
4.11.

Figure 4.11. Fuzzy control surface for DC servomotor control

The system can then be simulated using the Simulink package with the
system modeled in Figure 4.12. The simulation diagram presented in Figure
4.12 is slightly differentfromtheoneshownearlierinFigure4.6.Herewehave
opted to use the transfer function representation of the plant rather than the
state-space model, merely to illustrate variousMatlaboptions.Matlaballows
the conversion of state-space to transfer function, and from transfer function to
state-space representation very easily. The reader is urged to experiment with
these possible representations in order to build expertise in using a very powerful
and useful tool.