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Convert Mamdani fuzzy inference system into Sugeno fuzzy inference system



sugenoFIS = convertToSugeno(mamdaniFIS) converts the Mamdani fuzzy inference system mamdaniFIS into a Sugeno fuzzy inference system sugenoFIS.


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Load a Mamdani fuzzy inference system.

mam_fis = readfis('mam22.fis');

Convert this system to a Sugeno fuzzy inference system.

sug_fis = convertToSugeno(mam_fis);

Plot the output surfaces for both fuzzy systems.

title('Mamdani system (Output 1)')
title('Sugeno system (Output 1)')
title('Mamdani system (Output 2)')
title('Sugeno system (Output 2)')

Figure contains 4 axes objects. Axes object 1 with title Mamdani system (Output 1) contains an object of type surface. Axes object 2 with title Sugeno system (Output 1) contains an object of type surface. Axes object 3 with title Mamdani system (Output 2) contains an object of type surface. Axes object 4 with title Sugeno system (Output 2) contains an object of type surface.

The output surfaces for both systems are similar.

Input Arguments

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Mamdani fuzzy inference system, specified as a mamfis or mamfistype2 object.

mamdaniFIS must not contain rules with NOT logic in the consequent.

Output Arguments

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Sugeno fuzzy inference system, returned as one of the following:


  • Has constant output membership functions, whose values correspond to the centroids of the output membership functions in mamdaniFIS

  • Uses the weighted-average defuzzification method

  • Uses the product implication method

  • Uses the sum aggregation method

The remaining properties of sugenoFIS, including the input membership functions and rule definitions remain unchanged from mamdaniFIS.


  • If you have a functioning Mamdani fuzzy inference system, consider using convertToSugeno to convert to a more computationally efficient Sugeno structure to improve performance.

Alternative Functionality


You can interactively convert a Mamdani FIS into a Sugeno FIS using the Fuzzy Logic Designer app. You can then export the system to the MATLAB® workspace.

Version History

Introduced in R2018b

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