4.4. FUZZY CONTROLLER DESIGN 149
- If velocity error is PE and acceleration is NA, then engine force is Max.
- If velocity error is PE and acceleration is ZA, then engine force is Max.
- If velocity error is PE and acceleration is PA, then engine force is Max.
UsingMatlabthe fuzzy control surface can be developed as shown in Figure
4.5. Thiscontrol surfaceis the output plotted against the two inputs, and
displays the range of possible defuzzified values for all possible inputs. It is an
interpolation of the effectsoftheninerules.
Figure 4.5. Control surfaceNote that the control surface for a simple PD controller is a plane, which could
approximate this fuzzy control surface only in a small neighborhood of the origin.
The system can then be simulated using the Simulink package with the
system modeled as shown in Figure 4.6.
Figure 4.6. Simulink diagram for automobile cruise control
using a state-space model of the automobile
We describe briefly how to set up a simulation using the Simulink package
inMatlab. Simulink allows dynamic elements of a system to be connected
using both linear and nonlinear elements. Referring to Figure 4.6, the desired