You can test the relationship between the input and output values of a fuzzy system to validate the rule base of the fuzzy system.

Complete the following steps to test the vehicle maneuvering fuzzy system you created inthe previous steps.

  1. Click the Test System tab of the Fuzzy System Designer to display the Test System page.
  2. Enter an Input value of 5 for the vehicle-position input linguistic variable. Recall from creating the input linguistic variables in step 1 that a value of 5 for vehicle-position corresponds to the center linguistic term.
  3. Enter an Input value of -30 for the vehicle-orientation input linguistic variable, which corresponds to the left-down linguistic term.
  4. In the Invoked Rules table at the bottom of the page, notice that the fuzzy system invokes rule 15: IF 'vehicle-position' IS 'center' AND 'vehicle-orientation' IS 'left-down' THEN 'steering-angle' IS 'neg-medium'. Recall from creating the output linguistic variable in step 2 that the neg-medium linguistic term for the steering-angle variable corresponds to the range between -30 and -5. If you configured the fuzzy system correctly, the Output value indicator for the steering-angle displays a value within that range. The fuzzy controller calculates the Output value based on the weight of the rule, the consequent implication method, and the defuzzification method.
  5. (Optional) Use the Input variable 1 and Input variable 2 slide controls to sweep a range of values for the input linguistic variables and observe the corresponding changes in the Input/Output relationship graph. You can use this graph to verify that the rule base is reasonable and complete. For example, if the Input/Output relationship graph displays 0 at some points, the rule base might be incomplete.
  6. Fix any errors you find while testing and save the fuzzy system.
  7. Click the Close button to exit the Fuzzy System Designer.