getting error in fuzzy inference system & gain block

iam getting error iin FIS system opening even though i kept all files in one folder & its showing below error.

code:

clc; clear; close all;

%% =======================================================

% CHECK & OPEN SIMULINK MODEL CONFIGURATION

% *** PLEASE CHANGE THIS PATH TO YOUR ACTUAL FILE LOCATION ***

%% =======================================================

model = 'SimFuzzyPID';

modelPath = 'D:\trials_161125\1CP 25 705 (1)\final\SimFuzzyPID.slx';

% Extract folder path and add it to the MATLAB path for file finding

[folderPath, ~, ~] = fileparts(modelPath);

addpath(folderPath);

if ~exist(modelPath, 'file')

error('SimFuzzyPID.slx NOT FOUND at the specified path. Please check modelPath.');

end

load_system(model);

open_system(model);

disp(['Model "', model, '" loaded successfully.']);

%% =======================================================

% PLANT TRANSFER FUNCTION & DISCRETIZATION

% G(s) = [1250/(s^2 + 50s + 1250)] * [0.57s^2+2.64s+1] * e^(-0.2s)

%% =======================================================

s = tf('s');

G1 = 1250 / (s^2 + 50*s + 1250);

G2 = (0.57*s^2 + 2.64*s + 1);

Delay = exp(-0.2*s);

G = G1 * G2 * Delay;

Ts = 0.01;

Plant = c2d(G, Ts, 'zoh');

disp(['Plant discretized with Ts = ', num2str(Ts), 's.']);

%% =======================================================

% PID DESIGN USING pidtune (For initial gains)

%% =======================================================

C0 = pid(1,1,1,'Ts',Ts,'IF','B','DF','B');

C = pidtune(Plant, C0);

[Kp, Ki, Kd] = piddata(C);

disp(['PID Gains: Kp=', num2str(Kp), ', Ki=', num2str(Ki), ', Kd=', num2str(Kd)]);

%% =======================================================

% FUZZY PID SCALING GAINS

%% =======================================================

% You can tune these manually for better performance if needed

GE = 100; % Input scaling for Error (E)

GCE = GE * (Kp - sqrt(Kp^2 - 4*Ki*Kd)) / (2*Ki); % Input scaling for Change of Error (CE)

GCU = Ki / GE; % Output scaling gain (Ku)

GU = Kd / GCE; % Another output scaling gain (Ku * GCE / Kd, simplified)

disp(['Calculated Scaling Gains: GE=', num2str(GE), ', GCE=', num2str(GCE), ', GCU=', num2str(GCU), ', GU=', num2str(GU)]);

%% =======================================================

% BUILD FUZZY FIS (5 MFs Sugeno Structure)

%% =======================================================

FIS = mamfis("FIS","FISType","sugeno");

% --- Input 1: Error (E) ---

FIS = addInput(FIS,[-100 100],'Name','E');

FIS = addMF(FIS,'E',"NB","trimf",[-100 -100 -50]); % Negative Big

FIS = addMF(FIS,'E',"NS","trimf",[-100 -50 0]); % Negative Small

FIS = addMF(FIS,'E',"Z","trimf",[-50 0 50]); % Zero

FIS = addMF(FIS,'E',"PS","trimf",[0 50 100]); % Positive Small

FIS = addMF(FIS,'E',"PB","trimf",[50 100 100]); % Positive Big

% --- Input 2: Change of Error (CE) ---

FIS = addInput(FIS,[-100 100],'Name','CE');

FIS = addMF(FIS,'CE',"NB","trimf",[-100 -100 -50]);

FIS = addMF(FIS,'CE',"NS","trimf",[-100 -50 0]);

FIS = addMF(FIS,'CE',"Z","trimf",[-50 0 50]);

FIS = addMF(FIS,'CE',"PS","trimf",[0 50 100]);

FIS = addMF(FIS,'CE',"PB","trimf",[50 100 100]);

% --- Output: Control u (Constants) ---

FIS = addOutput(FIS,[-200 200],'Name','u');

FIS = addMF(FIS,'u',"NB","constant",-200);

FIS = addMF(FIS,'u',"NS","constant",-100);

FIS = addMF(FIS,'u',"Z","constant",0);

FIS = addMF(FIS,'u',"PS","constant",100);

FIS = addMF(FIS,'u',"PB","constant",200);

% --- Rule Base (25 Rules) ---

% Mapping: 1=NB, 2=NS, 3=Z, 4=PS, 5=PB

ruleList = [

1 1 1 1 1; 1 2 1 1 1; 1 3 2 1 1; 1 4 2 1 1; 1 5 3 1 1;

2 1 1 1 1; 2 2 2 1 1; 2 3 3 1 1; 2 4 4 1 1; 2 5 4 1 1;

3 1 2 1 1; 3 2 3 1 1; 3 3 3 1 1; 3 4 3 1 1; 3 5 4 1 1;

4 1 2 1 1; 4 2 3 1 1; 4 3 4 1 1; 4 4 4 1 1; 4 5 5 1 1;

5 1 3 1 1; 5 2 4 1 1; 5 3 4 1 1; 5 4 5 1 1; 5 5 5 1 1

];

FIS = addRule(FIS, ruleList);

disp('Fuzzy FIS defined with 5 MFs and 25 rules.');

%% =======================================================

% SAVE FIS TO FILE (Uses the model directory)

%% =======================================================

FIS_FileName = 'FuzzyPID_Controller.fis';

fullFilePath = fullfile(folderPath, FIS_FileName);

writeFIS(FIS, fullFilePath);

disp(['FIS file saved successfully at: ', fullFilePath]);

%% =======================================================

% SIMULINK PARAMETER PUSH & SIMULATION

% Push Kp, Ki, Kd, GE, GCE, GCU to the model (assuming blocks are named)

%% =======================================================

% Assuming you have a standard PID block named 'PID Controller'

% and a Gain block for PID named 'Kp_Gain', 'Ki_Gain', etc.

% set_param([model, '/PID Controller'], 'P', num2str(Kp), 'I', num2str(Ki), 'D', num2str(Kd));

% Assuming you have Gain blocks for the Fuzzy-PID scaling

% set_param([model, '/GE_Gain'], 'Gain', num2str(GE));

% set_param([model, '/GCE_Gain'], 'Gain', num2str(GCE));

% set_param([model, '/GCU_Gain'], 'Gain', num2str(GCU));

simOut = sim(model);

StepPID = simOut.StepPID;

StepFP = simOut.StepFP;

disp('Simulation complete.');

%% =======================================================

% PLOT RESULT: PID vs FUZZY-PID

%% =======================================================

figure;

plot(StepPID.time, StepPID.data,'LineWidth',2); hold on;

plot(StepFP.time, StepFP.data,'LineWidth',2);

grid on;

title('PID vs Fuzzy-PID Control Performance');

xlabel('Time (s)');

ylabel('Speed Response');

legend('PID','Fuzzy-PID');

Answer 1

[Sam Chak]

Hi @kirankumar

I have not tested the Simulink model because your code for generating the Sugeno fuzzy system contained several syntax errors, which I have corrected below.

Note that the control surface is diagonally asymmetrical. This may be acceptable when the system dynamics has asymmetrical nonlinear terms. However, your plant transfer function is linear with time delay, so the asymmetry may or may not affect stability.

% FIS = mamfis("FIS", "FISType", "sugeno");   % mamfis() creates Mamdani FIS only
% FIS = newfis('FIS', 'FISType', 'sugeno');   % this works but has been removed since R2024b
FIS = sugfis(Name="FuzzyPID_Controller");

% --- Input 1: Error (E) ---
FIS = addInput(FIS, [-100 100], 'Name', 'E');
FIS = addMF(FIS,  'E', "trimf", [-100 -100  -50], 'Name', "NB");    % Negative Big
FIS = addMF(FIS,  'E', "trimf", [-100  -50    0], 'Name', "NS");    % Negative Small
FIS = addMF(FIS,  'E', "trimf", [ -50    0   50], 'Name', "Z");     % Zero
FIS = addMF(FIS,  'E', "trimf", [   0   50  100], 'Name', "PS");    % Positive Small
FIS = addMF(FIS,  'E', "trimf", [  50  100  100], 'Name', "PB");    % Positive Big

% --- Input 2: Change of Error (CE) ---
FIS = addInput(FIS, [-100 100], 'Name', 'CE');
FIS = addMF(FIS, 'CE', "trimf", [-100 -100  -50], 'Name', "NB");    % Negative Big
FIS = addMF(FIS, 'CE', "trimf", [-100  -50    0], 'Name', "NS");    % Negative Small
FIS = addMF(FIS, 'CE', "trimf", [ -50    0   50], 'Name', "Z");     % Zero
FIS = addMF(FIS, 'CE', "trimf", [   0   50  100], 'Name', "PS");    % Positive Small
FIS = addMF(FIS, 'CE', "trimf", [  50  100  100], 'Name', "PB");    % Positive Big

% --- Output: Control u (Constants) ---
FIS = addOutput(FIS, [-200 200], 'Name', 'u');
FIS = addMF(FIS, 'u', "constant", -200, 'Name', "NB"); 
FIS = addMF(FIS, 'u', "constant", -100, 'Name', "NS");
FIS = addMF(FIS, 'u', "constant",    0, 'Name',  "Z");
FIS = addMF(FIS, 'u', "constant",  100, 'Name', "PS");
FIS = addMF(FIS, 'u', "constant",  200, 'Name', "PB"); 

% --- Rule Base (25 Rules) ---
% Mapping: 1=NB, 2=NS, 3=Z, 4=PS, 5=PB
ruleList = [1 1 1 1 1; 
            1 2 1 1 1; 
            1 3 2 1 1; 
            1 4 2 1 1; 
            1 5 3 1 1; 
            2 1 1 1 1; 
            2 2 2 1 1; 
            2 3 3 1 1; 
            2 4 4 1 1; 
            2 5 4 1 1; 
            3 1 2 1 1; 
            3 2 3 1 1; 
            3 3 3 1 1; 
            3 4 3 1 1; 
            3 5 4 1 1; 
            4 1 2 1 1; 
            4 2 3 1 1; 
            4 3 4 1 1; 
            4 4 4 1 1; 
            4 5 5 1 1; 
            5 1 3 1 1; 
            5 2 4 1 1; 
            5 3 4 1 1; 
            5 4 5 1 1; 
            5 5 5 1 1];
FIS = addRule(FIS, ruleList);

%  -------------------------
%% Intended to be used only during design stage to visually check the control surface
%  -------------------------
gensurf(FIS, gensurfOptions(NumGridPoints=51))

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