5. Specifying a Defuzzification Method

After you create the rule base for a fuzzy system, you must specify how a fuzzy controller performs defuzzification for the system.

In the vehicle maneuvering example, you must supply a continuous output signal to control the steering angle of the vehicle. Therefore, you must use a defuzzification method that calculates the best compromise between any rules that apply at a given time. According to the guidelines for selecting a defuzzification method the Center of Maximum (CoM), Center of Area (CoA), and Center of Sums (CoS) defuzzification methods all fit this requirement.

Complete the following steps to specify the defuzzification method.

1. On the Rules page of the Fuzzy System Designer, select the method you want to use from the Defuzzification method pull-down menu.
2. Select File�Save to save the fuzzy system.

The fuzzy system is complete. However, before you integrate the fuzzy system into the control structure you want to automate, you must test the functionality of the system.

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