How to identify the parameters of each membership function in a fuzzy logic system

I have a problem with the fuzzy toolbox , i don't know how to identify Params for each memebership fuction . The identification is based on what exactly ..?? How are the values in the vector are chosen ?? Please i really need your help

Answer 1

[Sam Chak]

Hi @Sebti Rihab

You can identify the parameters of each membership function (MF) in a designed fuzzy system using this simple script. Each parameter in a MF serves as a placeholder for a value that will be passed into the function when it is called. Taking the first input (Service) of the Fuzzy Tipper as an example, it consists of three Gaussian MFs. For Gaussian MFs, the first parameter is the standard deviation, and the second parameter is the center (mean).

The values for these MF parameters are generally determined by a qualified fuzzy logic expert. For designers who do not have a natural aptitude for mathematics, the genfis() function can be employed to automatically generate the desired MFs for the fuzzy system, provided that the appropriate input–output data is available.

fis = readfis("tipper");
figure
plotfis(fis)

fis.Inputs(1).MembershipFunctions

ans = 
  1x3 fismf array with properties:

    Type
    Parameters
    Name

  Details:
            Name          Type       Parameters
         ___________    _________    __________

    1    "poor"         "gaussmf"    1.5      0
    2    "good"         "gaussmf"    1.5      5
    3    "excellent"    "gaussmf"    1.5     10

fis.Inputs(2).MembershipFunctions

ans = 
  1x2 fismf array with properties:

    Type
    Parameters
    Name

  Details:
            Name          Type          Parameters     
         ___________    ________    ___________________

    1    "rancid"       "trapmf"    0     0     1     3
    2    "delicious"    "trapmf"    7     9    10    10

fis.Outputs(1).MembershipFunctions

ans = 
  1x3 fismf array with properties:

    Type
    Parameters
    Name

  Details:
            Name        Type        Parameters  
         __________    _______    ______________

    1    "cheap"       "trimf"     0     5    10
    2    "average"     "trimf"    10    15    20
    3    "generous"    "trimf"    20    25    30