how to implement fuzzy logic code without using fuzzy Toolbox

Hello.

I need to implement a fuzzy logic code in matlab without using toolbox, i have two input power and voltage and i should estimate power in the next time,membershiP function is triangular,defuzz method is center method.

fuzzy inference (power and voltage level) and each input have 6 membershipfunction as follow

input={power : very small,small, medium, large, very large and Voltage:very small,small, medium, large, very large }

output={power : NFl,OCF, SCF, Pars,BDPars, OCinv }

formarulebase:

1. if (power is very small and voltage is very smal), then NFI
2. if(power is very small and voltage is small,) then OCF
3. if(power is small and voltage is medium) then SCF
4. if (power is medium and voltage is medium) then BDPars
5. if(power is large and voltage is medium) then Pars
6. if(power is very large and voltage is medium) then OCF
7. if(power is medium and voltage is large) then SCF
8. if(power is medium and voltage is very) large OCinv
9. if(power is very large and voltage is very large) then OCF

Thanks for your helping at this problem,

[merlin toche]

please sir help me solve this problem on my fuzzy logic code.

here is the code and the error message that is displayed. attached code

Answer 1

[Sam Chak]

Hi @merlin toche

Some functions from the fuzzy logic toolbox in your code do not work on the much older R2015a release.

The toolbox does not a built-in function called "trmf()". Mostly likely you were trying to enter trimf(), which is the triangular MF. The MFs on the Grease look strange. Please check.

Edit: Check if the following code works in R2015a.

% Declare FIS Type (mamfis was introduced in R2018b)
% fis = newfis('fis', 'FISType', 'mamdani');  % for R2017a and newer
fis = newfis('Fuzzy_Car_Wash')          % Create a default Mamdani FIS.

% Input 1: Amount of Dirt
fis = addvar(fis, 'input', 'Dirt', [0 100]);
fis = addmf(fis, 'input', 1, 'Small',    'trimf', [ 0  0   50]);
fis = addmf(fis, 'input', 1, 'Moderate', 'trimf', [ 0  50 100]);
fis = addmf(fis, 'input', 1, 'Large',    'trimf', [50 100 100]);

% Input 2: Amount of Grease
fis = addvar(fis, 'input', 'Grease', [0 100]);
fis = addmf(fis, 'input', 2, 'No',       'trimf', [ 0   0  50]);
fis = addmf(fis, 'input', 2, 'Moderate', 'trimf', [ 0  50 100]);
fis = addmf(fis, 'input', 2, 'Large',    'trimf', [50 100 150]);

% Output: Wash Time
fis = addvar(fis, 'output', 'WashTime', [0 60]);
fis = addmf(fis, 'output', 1, 'VS', 'trimf', [ 0  0 10]);
fis = addmf(fis, 'output', 1, 'S',  'trimf', [ 0 10 25]);
fis = addmf(fis, 'output', 1, 'M',  'trimf', [10 25 40]);
fis = addmf(fis, 'output', 1, 'L',  'trimf', [25 40 60]);
fis = addmf(fis, 'output', 1, 'VL', 'trimf', [40 60 60]);

% Plot membership functions
figure(1)
subplot(3,1,1)
plotmf(fis, 'input', 1), grid on, title('Input 1: Amount of Dirt')
subplot(3,1,2)
plotmf(fis, 'input', 2), grid on, title('Input 2: Amount of Grease')
subplot(3,1,3)
plotmf(fis, 'output', 1), grid on, title('Output: Wash Time')

% Fuzzy Rules
% [In1 In2 Out Weight AndOp]
ruleList = [1 1 1 1 1;... % R1: if Dirt = SD & Grease = NG, then WT = VS
            1 2 2 1 1;... % R2: if Dirt = SD & Grease = MG, then WT = M
            1 3 3 1 1;... % R3: if Dirt = SD & Grease = LG, then WT = L
            2 1 2 1 1;... % R4: if Dirt = MD & Grease = NG, then WT = S
            2 2 3 1 1;... % R5: if Dirt = MD & Grease = MG, then WT = M
            2 3 4 1 1;... % R6: if Dirt = MD & Grease = LG, then WT = L
            3 1 3 1 1;... % R7: if Dirt = LD & Grease = NG, then WT = M
            3 2 4 1 1;... % R8: if Dirt = LD & Grease = MG, then WT = L
            3 3 5 1 1];   % R9: if Dirt = LD & Grease = LG, then WT = VL
fis = addrule(fis, ruleList);

% Plot Output Surface of Mamdani FIS
figure(2)
gensurf(fis)

% Save the designed fuzzy inference system in a FIS file (Fuzzy_Car_Wash.fis)
writefis(fis, 'Fuzzy_Car_Wash')

[merlin toche]

Hi @Sam Chak!

thank you for your interest in me. really, thank you.

absolutely you are right about my fat MF, there is indeed an error. nevertheless I corrected it is the same MF as Dirt.

I tried to run the code, but it shows the same error message: "Undefined function or variable 'mamfis'."

maybe as you said, the problem comes from the fact that my r2015a version is older. thank you for your help, I will come back to you soon for any requests please

best regards

[Sam Chak]

Hi @merlin toche

Most likely the issue is related to the Fuzzy Logic Toolbox. By the way, it is not the end of the world when the toolbox is unavailable. You can still mathematically construct the desired shapes of the Membership Functions and the define your preferred Defuzzification method. For simplicity and yet as good as Mamdani FIS, I suggest you use the Sugeno FIS.

x = linspace(0, 100, 10001);
m = 1/50*[1 1 1];                       % gradients
c = [0 50 100];                         % centres
y1 = max(0, 1 - m(1)*abs(x - c(1)));    % triMF 1
y2 = max(0, 1 - m(2)*abs(x - c(2)));    % triMF 2
y3 = max(0, 1 - m(3)*abs(x - c(3)));    % triMF 3
plot(x, [y1; y2; y3]), ylim([-0.2 1.2]), grid on
xlabel('Dirt')
ylabel('Degree of membership, \mu')
text(  0+1.0, 1.05, 'SD')
text( 50-2.5, 1.05, 'MD')
text(100-5.0, 1.05, 'LD')

Though you need write a few lines of code instead of using plotmf directly, it is possible to get the work done.

Anyhow, here is how you can check if you have the Fuzzy Logic Toolbox installed.

ver

-----------------------------------------------------------------------------------------------------
MATLAB Version: 9.13.0.2145394 (R2022b) Update 3
MATLAB License Number: 0
Operating System: Linux 5.4.224-0504224-generic #202211101403 SMP Thu Nov 10 21:10:29 UTC 2022 x86_64
Java Version: Java 1.8.0_292-b10 with AdoptOpenJDK OpenJDK 64-Bit Server VM mixed mode
-----------------------------------------------------------------------------------------------------
MATLAB                                                Version 9.13        (R2022b)
Simulink                                              Version 10.6        (R2022b)
5G Toolbox                                            Version 2.5         (R2022b)
Aerospace Blockset                                    Version 5.3         (R2022b)
Aerospace Toolbox                                     Version 4.3         (R2022b)
Antenna Toolbox                                       Version 5.3         (R2022b)
Audio Toolbox                                         Version 3.3         (R2022b)
Automated Driving Toolbox                             Version 3.6         (R2022b)
Bioinformatics Toolbox                                Version 4.16.1      (R2022b)
Bluetooth Toolbox                                     Version 1.1         (R2022b)
Communications Toolbox                                Version 7.8         (R2022b)
Computer Vision Toolbox                               Version 10.3        (R2022b)
Control System Toolbox                                Version 10.12       (R2022b)
Curve Fitting Toolbox                                 Version 3.8         (R2022b)
DO Qualification Kit                                  Version 3.14        (R2022b)
DSP System Toolbox                                    Version 9.15        (R2022b)
Database Toolbox                                      Version 10.4        (R2022b)
Datafeed Toolbox                                      Version 6.3         (R2022b)
Deep Learning Toolbox                                 Version 14.5        (R2022b)
Econometrics Toolbox                                  Version 6.1         (R2022b)
Embedded Coder                                        Version 7.9         (R2022b)
Filter Design HDL Coder                               Version 3.1.12      (R2022b)
Financial Instruments Toolbox                         Version 3.5         (R2022b)
Financial Toolbox                                     Version 6.4         (R2022b)
Fixed-Point Designer                                  Version 7.5         (R2022b)
Fuzzy Logic Toolbox                                   Version 3.0         (R2022b)
Global Optimization Toolbox                           Version 4.8         (R2022b)
HDL Coder                                             Version 4.0         (R2022b)
HDL Verifier                                          Version 7.0         (R2022b)
IEC Certification Kit                                 Version 3.20        (R2022b)
Image Acquisition Toolbox                             Version 6.7         (R2022b)
Image Processing Toolbox                              Version 11.6        (R2022b)
Industrial Communication Toolbox                      Version 6.1         (R2022b)
Instrument Control Toolbox                            Version 4.7         (R2022b)
LTE Toolbox                                           Version 3.8         (R2022b)
MATLAB Compiler                                       Version 8.5         (R2022b)
MATLAB Compiler SDK                                   Version 7.1         (R2022b)
MATLAB Report Generator                               Version 5.13        (R2022b)
Mapping Toolbox                                       Version 5.4         (R2022b)
Mixed-Signal Blockset                                 Version 2.3         (R2022b)
Model Predictive Control Toolbox                      Version 8.0         (R2022b)
Navigation Toolbox                                    Version 2.3         (R2022b)
Optimization Toolbox                                  Version 9.4         (R2022b)
Parallel Computing Toolbox                            Version 7.7         (R2022b)
Partial Differential Equation Toolbox                 Version 3.9         (R2022b)
Phased Array System Toolbox                           Version 4.8         (R2022b)
Powertrain Blockset                                   Version 1.12        (R2022b)
Predictive Maintenance Toolbox                        Version 2.6         (R2022b)
RF Blockset                                           Version 8.4         (R2022b)
RF Toolbox                                            Version 4.4         (R2022b)
Requirements Toolbox                                  Version 2.1         (R2022b)
Risk Management Toolbox                               Version 2.1         (R2022b)
Robotics System Toolbox                               Version 4.1         (R2022b)
Robust Control Toolbox                                Version 6.11.2      (R2022b)
Sensor Fusion and Tracking Toolbox                    Version 2.4         (R2022b)
SerDes Toolbox                                        Version 2.4         (R2022b)
Signal Processing Toolbox                             Version 9.1         (R2022b)
SimBiology                                            Version 6.4         (R2022b)
SimEvents                                             Version 5.13        (R2022b)
Simscape                                              Version 5.4         (R2022b)
Simscape Driveline                                    Version 3.6         (R2022b)
Simscape Electrical                                   Version 7.8         (R2022b)
Simscape Fluids                                       Version 3.5         (R2022b)
Simscape Multibody                                    Version 7.6         (R2022b)
Simulink 3D Animation                                 Version 9.5         (R2022b)
Simulink Check                                        Version 6.1         (R2022b)
Simulink Code Inspector                               Version 4.2         (R2022b)
Simulink Coder                                        Version 9.8         (R2022b)
Simulink Control Design                               Version 6.2         (R2022b)
Simulink Coverage                                     Version 5.5         (R2022b)
Simulink Design Optimization                          Version 3.12        (R2022b)
Simulink Design Verifier                              Version 4.8         (R2022b)
Simulink PLC Coder                                    Version 3.7         (R2022b)
Simulink Real-Time                                    Version 8.1         (R2022b)
Simulink Report Generator                             Version 5.13        (R2022b)
Simulink Test                                         Version 3.7         (R2022b)
Stateflow                                             Version 10.7        (R2022b)
Statistics and Machine Learning Toolbox               Version 12.4        (R2022b)
Symbolic Math Toolbox                                 Version 9.2         (R2022b)
System Identification Toolbox                         Version 10.0        (R2022b)
Text Analytics Toolbox                                Version 1.9         (R2022b)
Vehicle Dynamics Blockset                             Version 1.9         (R2022b)
Vehicle Network Toolbox                               Version 5.3         (R2022b)
Vision HDL Toolbox                                    Version 2.6         (R2022b)
WLAN Toolbox                                          Version 3.5         (R2022b)
Wavelet Toolbox                                       Version 6.2         (R2022b)
Wireless HDL Toolbox                                  Version 2.5         (R2022b)

If the Fuzzy Logic Toolbox was installed previously, then check the status of the license.

[status, errmsg] = license('checkout', 'fuzzy_toolbox')

status = 1

errmsg =

  0×0 empty char array

If the status output is 1 and the errmsg output array is empty, then you are good.

[merlin toche]

hello, thank you for the very quick return, your sensitivity goes straight to my heart!

however, as you mentioned, some functions of my toolbox may not work. yet the status is 1 showing that it is well presented. I tried to declare the function sugfis, but the same message is displayed as with mamfis. I'm confused.

very dear, please I am still an apprentice, can you accompany this piece of code with the comments (I do not understand this code well). please look at my attached code to better understand me. I'm new to ML and matlab.

thank you for your kindness

[Sam Chak]

Hi @merlin toche

I dug out some old documentations and revised the MATLAB code in my Answer above.

If the code works, please consider accepting ✔ and voting 👍 the revised Answer. Thanks a bunch! 🙏

[merlin toche]

Hi ! @Sam Chak

I really thank you for the efforts made to help me. your speed in the execution and the pedagogy in the explanation.

however good code, but unfortunately for me my R2015a version did not run this good code. here is the message displayed. I don't know if you have another alternative for me.

thank you again my dear, despite my quality of learner you manage to listen. really thank you and see you soon

[Sam Chak]

Hi @merlin toche

🤦‍♂️ Didn't know it went through a few changes over the last few years. I used to create the FIS using the GUI by typing the following commands at the MATLAB prompt:

fuzzy

or

fuzzyLogicDesigner

https://www.mathworks.com/help/fuzzy/newfis.html#mw_621232f3-e902-4cf4-b743-b69462696008

From the newfis() documentation, the name-value pair arguments are introduced in R2017a. That's why you got the error message. The simplest solution is to create a default Mamdani fuzzy inference system, by replacing this line

fis = newfis('fis', 'FISType', 'mamdani')

with this one

fis = newfis('Fuzzy_Car_Wash')

I have revised my Answer above. Let me know if this works so that we can have a proper closure.

[merlin toche]

Hi!

I'm very happy sir! your ease of explanation and your humility, thank you again. the revision you made has partially worked. partly because, an error message appeared at the level of the gensurfoption function. moreover, can't we replace "mamdani" by "sugeno"?

thank you again for your prompt reaction and your dynamism

see you later my dear

[Sam Chak]

Hi @merlin toche

https://www.mathworks.com/help/fuzzy/gensurfoptions.html#mw_787dfc80-892b-42c2-843b-722fc0f68ca4

Just discovered that gensurfOptions() was introduced in R2017a. I have removed that in the updated Answer.

https://www.mathworks.com/help/fuzzy/newfis.html?s_tid=doc_ta#mw_621232f3-e902-4cf4-b743-b69462696008

To create the Sugeno FIS, this is the general syntax for versions before R2017a.

fis = newfis('My FIS', fisType, andMethod, orMethod, impMethod, aggMethod, defuzzMethod);

This are the technical limitations of using the fuzzy toolbox in R2015a. Use the GUI Fuzzy Designer is more user-friendly if you still have problems with R2015a. If you have the opportunity, upgrade to R2022b through the university Campus-Wide License (if available).

[merlin toche]

@Sam Chak

thank you, thank you very much for your kindness

you teach me a lot about MATLAB and fuzzy logic, I'm going to compile this into a short course

Thank you again and see you soon

could I come back to you for everything in case I try fuzzyLogicDesigner please?

[Sam Chak]

@merlin toche, Yes, you can post a new question if you encounter a problem in fuzzyLogicDesigner. Don't forget to click-accept the Answer as a closure, once you verify that the revised code works for R2015a. It will also benefit to other users who are still using the older (pre-R2017a) versions.

[merlin toche]

thank you @Sam Chak

[merlin toche]

Hi @Sam Chak

please, there is no alternative to be able to display figure(2) apart from the gensurfOption function? since it doesn't work with R2015a.

Thank you and see you soon

[Sam Chak]

Didn't I remove that already in the updated answer? Can you post the error message?

[merlin toche]

thank you @Sam Chak

,I do it

[Sam Chak]

Hi @merlin toche

As mentioned previously, because you version is R2015a, then use this code:

% Plot Output Surface of Mamdani FIS
figure(2)
gensurf(fis)

[Sam Chak]

Hi @merlin toche

As mentioned previously, because you version is R2015a, then use this code:

% Plot Output Surface of Mamdani FIS
figure(2)
gensurf(fis)

[merlin toche]

Thank you very much@Sam Chak,

it work this code

i tried to use evalfis to get a result but it is no work

however, writefis is also unable to save designed fuzzy inference system. is it important to save it? if yes how do we proceed!

thank my dear

[Sam Chak]

@merlin toche, If you already have the code, then it is not so important to save it. If you want to save it, try importing (loading) the fis (as shown in Workspace) into the fuzzy logic app. Then, export it (save to) to the desired folder. This should be simplest way.

[Sam Chak]

@merlin toche. Any update?

[merlin toche]

Hi @Sam Chak

I come back to you momentarily. I'll get back to you, thanks for all your help.

[Sam Chak]

Hi @merlin toche

Did you accidentally accepted your own "Answer" (which in fact, is a comment)? Perhaps you did not realize you should click to accept the satisfactory answer to the question you asked.

You can unaccept your own "Answer" and move the contents to the "Comment" section below my "Answer".

[merlin toche]

Hi @Sam Chak and everyone

I hope my message finds you in good health.

thank you first of all for everything you do to support me in my work.

please, I would like to know how to interpret the results in fuzzy logic

for example here is attached my code on fault detection (NF OCF SCF PS PSBD)

I want to be able to explain the two figures obtained please

Thank you and see you soon

[Sam Chak]

Hi @merlin toche

Since the code works and if you find that the Answer (updated multiple times) and after-answer supports are satisfactory, please consider accepting ✔ Answer. Thanks a million! 💸🙏

------------------E-X-T-R-A------------------

Figure 1 shows what you designed for the membership functions, though I find it strange that the degree of LARGE membership of 30 V is 0. As if you are saying the 30 V is not Large at all. The same for OCF at FaultDetect = 50. Not OCF at all.

Figure 2 is the generated surface that described the relationship between these 3 variables (Current, Voltage, and FaultDetect) visually. If the surface is undesirable, then you have to modify shapes of MFs, and sometimes the Rules.

[merlin toche]

Hi @Sam Chak ,thank you very much for your pedagogy and your availability to help me. as I am still learning, apparently the difficulty is to define the membership functions. this is where really my dear, I am overwhelmed. hears expert, your pedagogy fascinates me, please can you explain to me more how to choose the membership functions and how to interpret the results? please, it is important for me thank you very much

for example here is a result that I got from the toolbox, could I have your help once again?

Thank you and see you soon!

figure1

figure2

[Sam Chak]

Hi @merlin toche

To be honest, I'm no expert on the PV system (which I guess from your file). But your revised FIS shows that the ranges are changed to [0, 100] for both current and voltage, without any technical reason explained to me. Moreover, I'm unable to interpret the revised Fuzzy Rules as seen in the GUI. Thus, I guess you mistakenly set the Rules.

Anyhow, the MFs and Surface looks more properly shaped in this update (newer than R2015a, change the code as needed). The surface is now symmetrical and stylishly-curved. With the shapes of MFs and the rules are now fixed, how good it affects the system performance depends the range you set. This should simplify you design work.

I'm more familiar with the model-based design. If the system model is available, I will analyze it and the findings will help me to decide on the shape of the MFs and where I should place them.

[merlin toche]

received thank you @Sam Chak

you are right, my ranges have changed, these are the data that I took concerning the various defects in a document to test my program. I actually haven't done my measurements yet. but as soon as I'm done with modeling my model, I'll let you know. by the way, my use fis is sugeno and not mamdani please.

in addition, @Sam Chak for me, given your knowledge and your mastery in this field, really bravo I say a thousand times thank you. frankly live forever, thanks to you I am starting to learn about MATLAB and machine learning.

thank you for all you do for the community.

apparently using the toolbox we don't have the same result, I tried and I see that it's not the same surface as what you have above

figure obtained with fuzzyToolbox

[Sam Chak]

Hi @merlin toche

Don't mention it. If you have some issues regarding the designed fuzzy PV system, I suggest you to post a new Question and attach the FIS file for investigation. Sometimes, keeping a long list of comments may derail from its original question.

I guess you saved the fis using the writefis() command and then reopened it (Import From File) using the FuzzyLogicDesigner app. But I'm not exactly sure what happened to yours. Probably there is a bug in R2015a fuzzy toolbox version. Mine looks the same as previously generated using gensurf(fis).

[merlin toche]

ok understood! just a question, i didn't save the file i rather entered my data using fuzzyLogicDesigner.

When I tried to save this is the error message I got.

how can I do? do we have an alternative?

as I told you, as soon as my PV system is ready I will let you know by posting as a new question.

thanks again

[Sam Chak]

@merlin toche, Mostly you entered incorrectly in the Rules.

By the way, the syntax in your image was incorrect. Perhaps you should refer to my attachment in this comment. The correct syntax is

writefis(fis, 'Filename');  % for version older than R2018b

as given here:

https://www.mathworks.com/help/fuzzy/mamfis.writefis.html