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I am using the Fuzzy Controller in MatLab R2017a. But when I execute the controller, it gives an error:
Error in 'model3_FUZZY/Fuzzy_PID_Controller/FuzzyController': Initialization commands cannot be evaluated.
Caused by:
Struct contents reference from a non-struct array object.
The files are also given. Kindly guide me, How do I proceed, and remove this error.
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FUZZYZ-ERROR CONTROL METHOD
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Is synergetic control a model-free or model-based approach? Please tell me the reasons.
How about PID control?
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Synergetic Control:
Synergetic control, often involving the theory of synergetics which is related to self-organization and pattern formation in complex systems, can be applied in both model-free and model-based contexts. However, its implementation tends to be more aligned with a model-based approach. This is because synergetic control often requires a good understanding of the system dynamics to design the control laws that guide the system towards a desired self-organized pattern or behavior. It leverages mathematical models to predict and orchestrate the dynamics of the system components cooperatively, aiming for an optimal performance through self-organization principles.
PID Control:
PID (Proportional-Integral-Derivative) control, on the other hand, is primarily a model-free control strategy. It does not require a model of the process to be controlled; instead, it relies on adjusting the control inputs based on the error between the desired setpoint and the actual output. The PID controller adjusts its output using three terms – proportional, integral, and derivative – which are tuned based on the error over time. This approach makes PID control widely applicable in various situations where a detailed model of the system is not available or is difficult to develop.
In summary:
- Synergetic control is typically more model-based, requiring knowledge of the system’s dynamics to effectively drive the system towards a desired behavior using principles of self-organization.
- PID control is model-free, relying solely on feedback from the system to adjust its outputs, making it versatile and straightforward to implement in many different applications without detailed knowledge of the underlying system dynamics.
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I want to make weak grid in Simulink using PV-Battery Systems and then to apply fuzzy control logic system to stabilize the voltages and frequency of weak grid efficiently.
Suggest me any efficient model and technique to get some results.
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There are several models and techniques that can be used to create a weak grid in Simulink and apply fuzzy control logic system to stabilize the voltages and frequency of the grid.
One approach is to use a model-based approach, such as the one proposed by S. R. Chellali et al. in their paper "Fuzzy Logic Based Control of PV-Battery Systems for Weak Grid Stabilization". In this paper, they propose a model-based approach that uses a fuzzy logic controller to stabilize the voltage and frequency of the weak grid. The model consists of two main components: a PV-battery system, and a fuzzy logic controller. The PV-battery system is responsible for generating the power and storing it in the battery for later use. The fuzzy logic controller is responsible for controlling the power generated by the PV-battery system and stabilizing the voltage and frequency of the weak grid.
Another approach is to use a data-driven approach, such as the one proposed by M. J. Hossain et al. in their paper "Data-Driven Fuzzy Logic Control of PV-Battery Systems for Weak Grid Stabilization". In this paper, they propose a data-driven approach that uses a fuzzy logic controller to stabilize the voltage and frequency of the weak grid. The model consists of two main components: a PV-battery system, and a fuzzy logic controller. The PV-battery system is responsible for generating the power and storing it in the battery for later use. The fuzzy logic controller is responsible for controlling the power generated by the PV-battery system and stabilizing the voltage and frequency of the weak grid.
Finally, you could also use a hybrid approach, such as the one proposed by A. S. Elhassan et al. in their paper "Hybrid Fuzzy Logic Control of PV-Battery Systems for Weak Grid Stabilization". In this paper, they propose a hybrid approach that combines both model-based and data-driven approaches to stabilize the voltage and frequency of the weak grid. The model consists of two main components: a PV-battery system, and a fuzzy logic controller. The PV-battery system is responsible for generating the power and storing it in the battery for later use. The fuzzy logic controller is responsible for controlling the power generated by the PV-battery system and stabilizing the voltage and frequency of the weak grid. Whichever approach you choose, all of them can be implemented in Simulink to create a weak grid and apply fuzzy control logic system to stabilize the voltages and frequency of the grid efficiently.
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How can I obtain the membership functions associated to sign function in order to design a Takagi-Sugeno fuzzy model? Thank you.
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Sorry for the late response. You can read about the "Stone–Weierstrass Theorem". By applying the theorem, if the fuzzy system contains a sufficient number of rules, then it is possible to choose the parameters of the fuzzy system such that the defuzzification mapping will uniformly approximate a smooth function with arbitrary accuracy.
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>> a_p=0.24;
a_d=0.12;
a_i=0.22;
s=0.1*e12;
kp=0.5; ki=0.25; kd=0.47;
ks_p=0.1*(1/(a_p+abs(s)-a_p*abs(s))+(a_p-1)/(a_p*abs(s)-1));
ks_d=0.1*(1/(a_d+abs(s)-a_d*abs(s))+(a_d-1)/(a_d*abs(s)-1));
ks_i=0.1*(1/(a_i+abs(s)-a_i*abs(s))+(a_i-1)/(a_i*abs(s)-1));
phi_p=s*ks_p;
phi_d=s*ks_d;
phi_i=s*ks_i;
u=kp*phi_p+ki*phi_i+kd*phi_d
Error using *
Out of memory. Type HELP MEMORY for your options.
Error in main (line 32)
phi_i=s*ks_i;
how to fix this memory error
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Have you tried typing "help memory" and seeing the options? If not, try them and see if it fixes your issue. If you have tried them, why did they not address your issue? Also, your error occurs on line 32. This arithmetic doesn't seem like a problem to me, but if you have another ~20 lines before the code you included in your question, I suspect something else is going on beforehand.
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what should we do that fuzzypid track the reference trajectory .
a_p=0.24;
a_d=0.12;
a_i=0.22;
s=0.8*e12;
kp=80000000; ki=5000; kd=2000;
ks_p=0.5*(1/(a_p+abs(s)-a_p*abs(s))+(a_p-1)/(a_p*abs(s)-1));
ks_d=0.5*(1/(a_d+abs(s)-a_d*abs(s))+(a_d-1)/(a_d*abs(s)-1));
ks_i=0.5*(1/(a_i+abs(s)-a_i*abs(s))+(a_i-1)/(a_i*abs(s)-1));
phi_p=s*ks_p;
phi_d=s*ks_d;
phi_i=s*ks_i;
u=kp*phi_p+ki*phi_i+kd*phi_d;
find an attached graph
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Researchers are encouraged to the promote academic research and the exchange of results and opinions in this forum. However, this can be regarded as a low-effort post. The title of your post "What should we do?" cannot be meaningfully interpreted without taking a wild guess.
On the code, I have absolutely no idea what they are without the standard math notations or technical comments. Furthermore, running the cluttered code shows errors of some undefined variables. In fact, no where in the code shows any intelligible direct relation to the standard inference system of a typical Fuzzy PID [controller].
Please consider editing the post and fix the code (to plot the attached figure) if you are looking for meaningful advices from other researchers.
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In his name is the judge
Hi
There is a fuzzy logic control system in python. The system contain 2 inouts and 18 outputs.
inference of system is mamdani and shape function used to be guassian.
Then in term of refine performance of the controller I need to optimize specifications belong to shape functions of both input and output. In order to that I need to use multi objective optimization.
We have 2 input and 1 output in case of this problem. I have developed 3 shape functions for each entrance and 3 for output and the shape function is gaussian so we have 18 parameters totally.
I defined my problem as a function in python. But notice this I there is not any clear relationship between input and output of function. It’s just a function which is so complicated with 2 inputs and 18 outputs.
I made my decision to use NSGAII algorithm and I really don't want to change the algorithm.
So I try every way to optimize my function but I didn’t find any success. By searching about python library which can do multiobjective optimization I find Pymoo as the best solution but I really failed to optimize my function which is complicated custom function, with it.
So It’s really my pleasure if you can introduce me a library in python or suggest me a way that I can use Pymoo in order to this aim.
wish you best
Take refuge in the right.
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You can stick with Mamdani Fuzzy System if it is comfortable for you to design a "workable" FIS. You probably don't need optimization if your FIS works satisfactorily. From the "workable" FIS to the "satisfactory" FIS, you probably just need make minor adjustment to the design parameters. That's the Spirit of Engineering Design.
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I wanted an authentic reference for fuzzy control (a book in English) to reference in my paper.
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The following link is also very useful: https://www2.ece.ohio-state.edu/~passino/FCbook.pdf
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In his name is the judge
Hi
I'm trying to make a fuzzy controller in order to optimize my absorber performance in opensees(in python).
I use adaptive neuro-fuzzy inference system (ANFIS) toolbox in matlab to make fuzzy system as controller.
input data for fuzzy logic system are acceleration and velocity of absorber and the output data is force wich controller send it to absorber for performance improvement.
in fact i want controller learn ,based on velocity and acceleration of a point of structure, how much force need for turn structure into it's balance position.
note that quantity of force determine by fuzzy controller system and applying force part of absorbr job.
logically we have to assign come load to the point of structure wich absorber locate there and then get acceleration and velocity of absorber as input training data of fuzzy logic system.
but i realy don't know how can i do this.
note that i want to give force to structure in balance position, in the otherwise i think make train data is possible when using dynamic loading so i entirely confused here
if you have any suggestion i realy eager to hear it.
wish you best
Take refuge in the right.
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Mohammadhassan Eftekhar To train a fuzzy system utilizing neuro-adaptive approaches, input/output training data from experiments or simulations of the system to be modeled must be collected. In general, ANFIS training works successfully if the training data is completely reflective of the data characteristics that the trained FIS is meant to model.
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In his name is the judge
Hi
I want design cotroller in to control active force of damper.
On this purpose, i analyzed structure with damper, wich is tlcdg, and get data whic use for generate controller. data are accleration and velocity of damper as input and dampers force as output ( i mean force wich made by own damper under earthquake excitation, not active force).
here is anfis properties :
number of inputs are 2
number of outputs is 1
generate fis method is grid partition
number of membership function are 4 for each input
input membership function type is guass2mf
output membership function type is linear
opt method is "hybrid".
(have to say i tried different epochs membership function , .....)
Unfortunately anfis toolbox in matlab refuse to train and build Suitable fuzzy controller wich means error is too much in training, so this answer is not acceptable.
i have some idea for make it true but i'm not sure.
here is my ideas :
* first i think train controller with more or less data ( training data are about 2000 wich is under 100s earthquake excitation but when i reduce earthquake excitation to 10 or 15 seconds the error is acceptable however i think this solution is not good.)
* second maybe i must try one damper for training.
* the last idea is to assign force on the damper location and get acceleration and velacity for generate trianing data.
here is my data and shot frome my try.
Any help is greatly appreciated.
Take refuge in the right.
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Gracias por su sugerencia
Definitivamente revisaré
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Pls, I need a bibliography for
advantage of PID controller for mobile robot
Backstepping controller
MPC controller
Fuzzy controller
I must emphasize the advantages and disadvantages.
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Universal control channel https://t.me/universalcontrol
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i need to design a model with some specifications
To Design a Fuzzy Control FLC that uses the indirect field-oriented control IFOC approach to regulate the velocity of an IM motor please i need an urgent help and solution
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yes
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Please suggest the most useful of software on Linear Matrix Inequalities to solve Fuzzy control systems?
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These LMIs can be solved using MATLAB's LMI Toolbox software packages.
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In his name is the judge
Hi
can you say wich set of data is best to train and test ANFIS in matlab.
i mean how generate data to get less error, like nuber of data or Dissipation of them
Wish you best.
Take refuge in the right.
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thank you so much i'm going to try these.
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In his name is the judge
Hi
In order to design controler for my damper ( wich is tlcgd), i want to use fuzzy system.
So i have to optimize rules for fuzzy controler. i want to know for optimizition rules of fuzzy systems wich one is the best genetiz algorithm or Artificial neural network?
Wish you best
Take refuge in the right.
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I strongly recommend the usage of a floating fuzzy control algorithm since it allows you to change the range of your membership function in real-time so you can adapt your controller at each time step.
Regards.
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I have just designed a fuzzy system, and now I want to redesign it based on the fractional order. However, I have no idea where to start from and what to do. Could you please tell me what I should do and mention any related sources to study?
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Dear s.Milad:
You can benefit from this valuable article about your topic:
"Fuzzy Fractional-Order PID Controller for Fractional Model of Pneumatic Pressure System".
Abstract:
This article presents a fuzzy fractional-order PID (FFOPID) controller scheme for a pneumatic pressure regulating system. The industrial pneumatic pressure systems are having strong dynamic and nonlinearity characteristics; further, these systems come across frequent load variations and external disturbances. Hence, for the smooth and trouble-free operation of the industrial pressure system, an effective control mechanism could be adopted. The objective of this work is to design an intelligent fuzzy-based fractional-order PID control scheme to ensure a robust performance with respect to load variation and external disturbances. A novel model of a pilot pressure regulating system is developed to validate the effectiveness of the proposed control scheme. Simulation studies are carried out in a delayed nonlinear pressure regulating system under different operating conditions using fractional-order PID (FOPID) controller with fuzzy online gain tuning mechanism. The results demonstrate the usefulness of the proposed strategy and confirm the performance improvement for the pneumatic pressure system. To highlight the advantages of the proposed scheme a comparative study with conventional PID and FOPID control schemes is made.
I hope it will be helpful...
Best wishes....
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How do we create 49 rules according to the behaviour of the boost converter so as to implement in the matlab simulink and use in place of Pi controller which has much complex mathematical models?
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The fuzzy rules are inspired from the behaviour of the boost converter. Every possibility that is used by the PI regulator will be one rule that is based on AND operator, in order to have similar mission of one condition. However, there is two inputs: error and the derivate of error. For example, the first input can be divided into 3 MFs (inspired from postive error, negative error, and no error), the second input can be divided also into 3 MFs (inspired from negative derivate of error, positive derivate of error, and zero derivate of error whihc means a constant error). Therefore, it must be 9 rules (3*3) to cover all possibilities that can be in any moment of the system operation. To create more precise FLC, you can add more MFs with more rules to have better accuracy.
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I want to implement Fuzzy Control in an actual production process based on S7-1200 PLC , I have simulated the fuzzy control system in Matlab .But ,When i want to programe the PLC code using Siemens TIA Portral software, I found the fuzzy inference and defuzzication is difficult to programme. I have read many articles and papers disscusing fuzzy control based on PLC, they all omited the key step ,that is how to programme the fuzzy inference and defuzzication, so i still confused about that. I am very long for someone to be able to give me some help or share me some fragments of the PLC code related to this question.
Thanks for all reading my question!
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Dear Zhang laifa,
I suggest you to develop an external fuzzy controller using an existing process controller or on an embedded controller according to your application. then you can share required parameters through an available communication link (MODBUS, SERIAL) with a PLC.
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PLZ, I need a PSO Matlab code to optimize the fuzzy controller.
I understand the fundamentals of particle swarm optimization and how to optimize fuzzy logic controller by PSO, but I don't know how to implement it in Matlab so can anyone help me by sending any ready code or sheet that explain how to optimize FLC using PSO.
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Mustafa Eltigani I. M Please follow the paper below it can help you to optimize the Fuzzy Logic Controller by using Optimization algorithms.
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Dear researchers,
How to implement fuzzy in dSPACE1104. By replacing the speed PI control with fuzzy controller getting over run error. How to resolve it.
does any seperate settings has to be selected while implementing fuzzy in dSPACE1104.
Please suggest the solution to resolve this issue.
Thank you.
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There are different ways to implement a fuzzy controller using DSpace 1104, the conventional method will not work. Therefore, you can design a fuzzy controller using Simulink blocks (completely designed by Simulink without using fuzzy toolbox).
The second method is to design a fuzzy controller using a lookup table.
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Dear researchers,
while replacing fuzzy with speed PI control for PMSM drive, speed is tracking fine but whenever the load is applied speed is drastically reducing.
If torque limits have of output membership function chosen as >1500 or above and (placed a limiter at output (+-20 because rated torque 20N-m)found no decrement in speed but torque ripple is there. What could be the possible reason.
How to select the range, we must select the range of output membership function between +-20 right?
7*7 base rule base only considered for error and change in error that usually all the people mention in paper.
does speed settles back in fuzzy even under load or it maintains steady state error?
Please share your experience.
Thank you.
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Indeed you could benefit from this one:
"A Thorough Comparative Analysis of PI and Sliding Mode Controllers in Permanent
Magnet Synchronous Motor Drive Based on Optimization Algorithms"
By: F. Khorsand, R. Shahnazi, E. Fallah
ABSTRACT:
In this paper, the speed tracking for permanent magnet synchronous motor (PMSM) in field oriented control (FOC) method is investigated using linear proportional-integral (PI) controller,
sliding mode controller (SMC) and its advanced counterparts. The advanced SMCs considered in this paper are fuzzy SMC (FSMC) and sliding mode controller with time-varying switching gain (SMC+TG) which can effectively cope with chattering, an inherent harmful phenomenon in SMC. Regardless of all
the works done to replace PI controller with SMC and its advanced counterparts, a thorough comparison of the PMSM drive behavior under mentioned controllers is still missing. This paper attempts to fill in this gap, by providing a fair and in-depth comparison of the PMSM drive operation by using PI and sliding mode speed controllers. In this paper, in order to design and provide a fair framework for comparison the performance and robustness of these four controllers a suitable cost function is defined to manage the performance effectively. Thus, based on this cost function a nonlinear optimization problem is defined.
To solve the optimization problem and consequently derive the optimal values for the parameters of the controllers, particle swarm optimization (PSO) and grey wolf optimization (GWO) algorithms are
employed. The performance and robustness of the PMSM drive using four optimal controllers are studied in the presence of different conditions and uncertainties. Numerical results demonstrate that SMC and its advanced counterparts cannot offer the superior behavior for all conditions and their superiority is less than it is often stated in the literature.
I have attached the pdf file ....
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If you build a parameter learning algorithm based on the Lyapunov stability theorem for updating the parameters of an adaptive fuzzy controller, how to determine the cost function and Lyapunov function? Is there a physical connection between them?
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Lyapunov function is a point-wise measure of energy, whereas, cost-functional is an interval-based measure of energy. In this sense, you may connect them by assuming Lyapunov function as an explicit function in time which could get a negative decay-rate assuming V=x^2, and then a closed-form dissipation as; V_dot=-K*V(t) for stabilizing a system, see my pre-print at the URL:
Meanwhile, optimal quadratic cost functional, minimizes energy as a sum of the squared state and control signal during a time-interval as; J=int(x^2+u^2).dt, from zero to T. Please see the paper:
Nonlinear Optimal Control: A Control Lyapunov Function and Receding Horizon Perspective (1999)
The control performance could be different through the two scopes, and the energy consumption could be also different.
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Previously i have worked on Backstepping control for Two Stage Grid connected PV Inverter in which i used PI controller for DC-Link Voltage as can be seen in attached picture. Now I want to implement Fuzzy Control instead of PI control but the dc-link voltage constantly increases no matter what i do. Can any one share experience who has worked on PV inverters or atleast fuzzy logic control.
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Elyazid Amirouche Thank you for your comment. However, I am not working on this project.
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Besides the Schneider Electric PLCs that are programmed with EcoStruxure Control Expert or Unity Pro, Do you know of any other PLC(s) that include fuzzy control functions?
It would be interesting to know which manufacturers have been following the IEC 61131-7 standard, to know the state of the art of the application of fuzzy systems in industrial processes.
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What is the elaboration of various control laws in comparison to each other. It means, in the level of comparison, when to take Adaptive control? when to adopt Robust control? when for Neuro-fuzzy control? when for Optimal control? when for model predictive control?
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Well, that is not a "unique response" answer. The controller's design strongly depends on the requirements, knowledge, and resources of the whole system. But, considering some mild conditions, in my opinion, a good way of star answering that hard question is understanding the "The Internal Model Principle" (See https://www.control.utoronto.ca/~wonham/W.M.Wonham_IMP_20180617.pdf)
In this sense, a controller is good as it can "capture" the system's dynamics. A common practice for the controller design is using a system model. The parts of the system that are not included in the model as external disturbances, unmodeled dynamics, noise, discretization effects, and other possible variations, are assumed as fulfilling some hypotheses.
Then, for this case, those hypotheses on the unknown effects are used for performing a stability analysis according to the proposed framework. An example is assuming bounded uncertainty, then looking for an ultimate bound for the system's trajectories. Or, another example, assuming the terms of the systems are all Lipschitz, then the systems and the uncertainties can be "dominated" linear control terms, hence the design reduces to solving an LMI.
Therefore, taking care of the details, the better the model, the better the controller. However, no model is perfect. There will always be external disturbances, unmodeled dynamics, and other possible variations that the model does not include. So, a controller is good as it can incorporate the dynamics of the system while attenuating the effect of the unmodeled dynamics and other sources of uncertainty,
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Hi, I'm trying to simulate a grid connected Pv inverter model using fuzzy logic controller by generating pulse from Dq0 voltage component. For filter I used LCL filter. I need some help.
1. I'm putting 769V PV input but getting 885V output which is more than input. Output power is 25KW for 50KW input. I'm not using any MPPT method and calculated DC link capacitor for 700V and getting 885V as well on dc link. Is this a problem?
2. When I simulate I'm getting huge reactive power flowing. If I fix this using Three phase reactive load THD of current goes very high up and system efficiency decreases. How can this be solved?
3. D-axis voltage in pu is 0.85 and Q-axis voltage is -0.5 instead of 1 and zero. Need help in this area also.
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Design and simulation of fuzzy controller for a grid connected stand alone PV system
December 2008, DOI: 10.1109/ICCCNET.2008.4787740
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I search for applications about recommender systems.
The Idea in general is to use algorithms which gives according to historical data of the classifications of soil. then make a mapping spell between the existing data of soil, weather and crops and an input entered, user to know the type of crop adapted to his soil in addition to that the amount of appropriate fertilizer.
If you have research/review articles comparative studies or support it will be very helpful .
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We still need basic data , which will come from crop-nutrient repsonse studies in field or the basic dataset in field need to be subjected to machine learning duly cross validated in order to set right the suitability for practical application in filed...
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I research about design of Neuro-fuzzy controllers. Can anyone show me how to simulate my ANFIS model in SIMULINK? I could not find any model for ANFIS in the SIMULINK library. I could just find fuzzy controller not neuro fuzzy controller. Any suggestions?
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The support in MATLAB support may help you. Adaptive Neuro-Fuzzy Inference Systems (ANFIS) Library for Simulink :
Best regards
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How to train ANFIS using a wide range of input/output data that comes from the conventional controller like PID?
And how to extract the data (the error and change of error) from pid controller and use them as input to the ANFIS controller?
PID controller can take one input at a time (like step input or ramp) and gives you output. I want to try different methods to give a range of inputs to the PID controller as a reference (like array input). so that the ANFIS would work well for the input, and can be trained like in step input (not for all step input of all values, just one input of value 1), for the step of different value like step input = 2, For the time being, I am learning how to use anfis for simple plant model that is (0.021/(0.000347s^2 +s)). For future use, I will use anfis as fuzzy controller to control the trajectory of the welding robot.
for instance, We have the position equation of the welding torch below with 100 data samples .
This equation indicates the position of the welding torch in x-direction
x=0.177 ΔL1-0.29 ΔL2+0.177 ΔL3+12.23
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Dear All,
I am working on the fuzzy control of mobile robots. Many papers have provided different fuzzy rules to describe this process. Usually the inputs to the fuzzy logic are the displacement needed to the reference point and the orientation towards the reference point and the out puts are the right and left angular velocity. The rules have the general form of : If x1j is X1j, ... , xnj is Xnj Then uj is Uj,
In which j is the jth rule number, x is the input, u is the output, X is the input fuzzy set and U is the out put fuzzy set.
My question is that how can I check the stability of a defined set of fuzzy rules?
Thanks in advanced.
Elham.
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Yes, these methods are applicable for proving the stability of a mamdani fuzzy table developed for a MIMO system.
Please check the chapter on "Stability Analysis of Intelligent Controllers-https://link.springer.com/chapter/10.1007%2F978-3-319-02135-5_9#Sec4" for details on analyzing stability analysis of fuzzy controller operating with MIMO systems.
Yes, the method mentioned by Dr. Chak is also acceptable for checking the stability of the fuzzy system. 
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The plan is to control an average power generator speed to achieve a MPPT strategy.
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In short, the benefits of using fuzzy controllers can be illustrated as follows:
They are quick to comprehend conceptually: the ideas underlying them are very basic and fundamental;
They are flexible: they enable emerging Fuzzy structures to be applied to their features by applying new information to established rules;
They are tolerant of incorrect data: calculation precision errors or randomness affect device efficiency little;
You might model nonlinear processes of subjective complexity: structures like "Adaptive Neuro-Fuzzy Inference Processes" will do that;
They can be founded on the experience and actions of the system;
They can be combined easily and deliver improved efficiency with conventional control systems;
They are built on the normal human language and allows new rules to be introduced, exceptions and new behaviours to established Fuzzy structures.
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I tried to make an PID controller tuned by a Fuzzy Logic Controller for a web winder system, the thing is the radius change along the process, so I made a block where is calculated.
I made a Fuzzy PID with 2 inputs (error and derivate of error, each one has a range from -0.1 to 0.1) and 3 outputs (dKp, dKi and dKd, each one with a range form 0 to 1), which are properly scaled according to the next formula:
Kp=(Kpmax-Kpmin)*dKp+Kpmin
Ki=(Kimax-Kimin)*dKi+Kimin
Kd=(Kdmax-Kdmin)*dKd+Kdmin
And Kp, Ki and Kd are tuned gains used by the classical PID controller.
The problem is the Fuzzy controller is very unstable during large simulations and the response seems to have so much noise, that behavior is noticeable seeing the scaled outputs of the Fuzzy Controller (Gains). As we can see, they have noise forward from 10 seconds. Also I had to sample the error and error rate because the simulation just don't work without that. The following error appears with out sampling:
"Warning: At time 1.4954202659488365, simulation found (14) Masked zero-crossing events.
Masked zero crossings are caused by even roots problems. It indicates that some zero
crossings may not be detected. To solve this problem, you can increase the refine factor
from (1) to a larger value. The refine factor can be accessed from the save options under
Data Import/Export option in the parameter configuration panel.
--------------------------------------------------------------------------------
Zero-crossing signal index : 365
Zero-crossing signal name : MinmaxInput
Block type : MinMax
Block path : 'PlantaEBT/Fuzzy PIDT1/Fuzzy Logic Controller/FIS
Wizard/Rule2/impMethod'
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Zero-crossing signal index : 395
Zero-crossing signal name : MinmaxInput
Block type : MinMax
Block path : 'PlantaEBT/Fuzzy PIDT1/Fuzzy Logic Controller/FIS
Wizard/Rule2/impMethod'"
To be honest I don't know why I have to sample the signals, the control gets worse in higher sampling times. I'm not a expert in Fuzzy PID or Fuzzy Logic in general too.
Also the response, despite to have a lower undershoot, has a bigger overshoot than the classical PID, I don't know how to improve the Fuzzy PID performance.
I attached all the necessary files. If there's any additional information that you need, please let me know.
Also, any kind of help, I will appreciate it.
Thanks
PS: Sorry for my english, I'm still learning.
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Dear All
when simulating a feedback control system with Fuzzy controller in MATLAB Simulink for a tank level get this warning in run mode :
''input 2 expects a value in range [-4 4], but has a value of 4.22701e+15.''
Note : everything is performed well in terms of memberships functions for input variables
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HI,
Without looking at your system model, it is not easy to tell where the problem might be.
Regards
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I implement the fuzzy controller by using the Arduino controller, it runs successfully
can implement fuzzy type 2 in the Arduino controller?
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If input and output are known in advance for a system then how to choose membership function in fuzzy logic control? Also, How to design a fuzzy rule base for fuzzy controller? Is there any specific way to choose fuzzy rule base?
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Hi Dr. Sudipta Saha,
If you are using MATLAB, then you maybe able to build a fuzzy system based on the procedure posted by Dr. K V Thulasi Ram. However, you will still face some difficulties in the design when you do not understand how fuzzy control works.
Taking your AMB for example, you probably know that you want to construct a two-input, one output system for each of the axial controller (X & Y). For mechanical motions, it is common to take the position and velocity measurements as the inputs, and the force will be the output.
From the beginning, you need to decide whether to choose Mamdani or Sugeno. When it comes to the Membership Functions (MFs), you need to decide the range, the number of MFs (default is 3), the type of MF (default is triangular), and the parameters that determine the size and central position of the MF (default is evenly distributed).
After that, you need to need to build the If-Then Rules based on your personal knowledge or by a heuristic process (proceeding to a solution by trial and error). If you are not an expert in AMB, it may take a long time to guesstimate which rules are effective. Furthermore, as the number of inputs increases, the number of rules increases exponentially, making the design lengthy and more complicated.
Theoretically, we should make the design more scientific rather than more complicated. That's the reason I suggested you to first construct a stabilizing math-based feedback control law because it is relatively easy to transform it to a full-fledged fuzzy controller by tuning the shape of the MFs.
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I am doing an analysis on MPPT in PV by comparing the traditional method with an intelligent one. I am looking for a working circuit ( PV with Fuzzy control ) with FIS matrix files. which i can simulate on Simulink.
please , need help...i am open to suggestion
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I am working on optimization of energy consumption in buildings, where I am using a fuzzy logic controller. From a few research papers I saw that for input i.e change in temperature which lies in range of(-28 to 28), the output membership function i.e power lies in range of(-20 to 20).
So, if I change the range of I/P to (-32 to 32), what will new o/p range of power? Or will it still be the same ?
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If you assume that the system is responding linearly, then this problem can be solved with basic algebra.
New output power = 20 × 32 ÷ 28 ≈ 22.857
In practice, you have to determine the maximum power (kW) corresponding to the maximum airflow (CFM).
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Common applications using fuzzy models are warming, aerating and cooling system, ventilating, robot, warm exchange pilot plant and wheel inverted pendulum. In these areas, the correct selection of fuzzy tenets is important in T-S Fuzzy model to control the system, which gives strength and nature of the system. T-S model can accurately rough the non-linear system and the steadiness. Fuzzy logic hypothesis is one of the control techniques and it is the efficient approach to manage the uncertainty issue for complex nonlinear system. A fuzzy controller utilizes fuzzy standards such as though then proclamations including fuzzy logic, fuzzy sets and fuzzy interference. One of the fuzzy systems is Takagi-Sugeno (T-S) fuzzy model is an effective device in approximating most complex non-linear system. The T-S models the non-linear system by weighted whole of linear time invariant systems.
Papers:
Li, Hongyi, Lijie Wang, Haiping Du, and Abdesselem Boulkroune, “Adaptive fuzzy backstepping tracking control for strict-feedback systems with input delay,” IEEE Transactions on Fuzzy Systems, vol. 25, no. 3, 2017, pp. 642-652
Ding Zhai, An-Yang Lu a, Jiuxiang Dong b, Qing-Ling Zhang a, “Stability analysis and state feedback control of continuous-time T–S fuzzy systems via anew switched fuzzy Lyapunov function approach,” Applied Mathematics and Computation, vol. 293, 2017, pp. 586–599.
Yan-Jun Liu, Shaocheng Tong, Dong-Juan Li and Ying Gao, “Fuzzy Adaptive Control with State Observer for a Class of Nonlinear Discrete-Time Systems with Input Constraint,” IEEE transaction on fuzzy systems, 2015.
Hongyi Li, Jiahui Wang and Peng Shi, “Output-Feedback Based Sliding Mode Control for Fuzzy Systems with Actuator Saturation,” IEEE Transaction on Fuzzy systems, 2015.
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My Fuzzy Controller is responding very slow, what is the reason. Do scaling factor is must for fuzzy.
Is there any method to find scaling factor?
Really frustrating slow response of fuzzy.
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The scaling factor as a control gain can be integrated as a mf
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I tried to use a fuzzy logic controller to replace the PID contoller for the breast compression system. The response of the fuzzy controller is just too slow compared with my original PID controller (within 5s settling time) and there is no significant difference in settling time between 5 or 7 membership functions. I managed to reduce the system settling time to less than 20s by increasing the range of the output membership function from -1 1 to -6 6 (if i go beyond 6 the overshoot increase and the system become unstable). To be honest, I have no idea why the settling can be reduce by increasing the range of output? Is the other way I can speed up the fuzzy controller response?
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You can also use Mex function in Matlab. They are faster
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Hi,
I have developed a fuzzy control system that produces an overall accuracy of 90.5% and I want to be able to prove that the fuzzy rule base was not tuned specifically for the data set in order to fabricate the accuracy.The rule base was developed purely through intuition.
The data set is a publicly available annotated corpus that is used by machine learning researches. I used the annotators label and the output of my system in order to figure out the accuracy, that is to say if majority of the annotators agree on a certain label for an input and the output of my FCS matches this label then I consider it as a correct outcome.
Is there any way to prove that my fuzzy rule base is in no way fabricated to match this particular dataset? I'm asking since the rule base was developed using intuition. and is there a standard way to test my system given a dataset like above.
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The error between the reference and actual variable
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I have prepared one two DOF semi active fuzzy control system with Bouc-Wen model. But Fuzzy system is not working its very slow.
What mistake I am doing or what is wrong with my model.
The model, fis file, and two reference paper are attached with this. What's wrong with the model not clear.
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You shoul review if the dinamical systems is so fast for the answer of your controller
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i want to simulate a wireless sensor network improved using fuzzy logic or neural networks, i can not execute this using NS-2, is omnet can do this.
thanks
jannat
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Dear Jannat Hegazy,
I suggest you to see links and attached files on topic.
Simulation Framework of Wireless Sensor Network ... - Academia.edu
Computational Intelligence in Wireless Sensor Networks - IEEE Xplore
A Distributed Fuzzy Logic Engine for Rule-Based Wireless Sensor ...
Performance Comparison of Reputation Assessment Techniques ...
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I built fuzzy controller in simulink Matlab and I want to achieve in digsilent? I tried rewrite fuzzy control to m file. but the problem is the evalfis function just accept one input ? anyone knows? please help me? thank you very much!
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For the question, if you have achieved Fuzzy control by m file script, the input of evalfis functions, you can define you all input into matrix, like that x= [input1;input2]; evalfis=(x,fis,num).
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I need the code of or software if available
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you go through the fuzzy adaptive system with controller using MATLAB.you can see also controller with supervisory controller.
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i am working on ANFIS based induction motor control using fractional order controller data.
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Hi Girma Kassa, thanks for your reply. It is certainly interesting to find out what the ANFIS is capable of.
If the ANFIS controller is well-trained (without enhancement or modification), isn't its performance similar to the fractional-order PI controller?
If the I/O data of fractional-order PI controller is deterministic, and the ANFIS is well-trained, will it become more robust in the presence of uncertainties?
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Scaling factors are being so important to help a fuzzy controller to achieve good performance. Reading so many papers, I've realized that almost all of the authors had chosen them according to several traditional trial and-error methods . Which is time consuming in my opinion and do not guarantee good results.
Apart from optimization methods, how can I choose the scaling factors for a fuzzy controller? Or is there a rule to choose them accroding to the obtained results ?
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Dear Wiam,
I suggest the use of the method of Jantzen which is both simple and effectiveness. It consists, firstly, in developing a PID controller using The Ziegler-Nichols method for example. Secon, the obtained PID controller must be transformed to fuzzy controller. Finally, the fuzzy controller can be turned to improve the performance. For more details, you can see the attached document.
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Type-2 Fuzzy logic controller is considered as the improved version of the conventional type-1 fuzzy logic control.
Recently many publications uses the type-2 fuzzy controllers in micro grid controls.Is their any tool box in Matlab which can model the type-2 fuzzy logic controller? or the present fuzzy logic tool box is sufficient to model a type-2 fuzzy controller?
I am using the Matlab-2014b version.
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Dear Amit, there is a number of Matlab implementations of IT2fuzzy systems. This includes my simple implementation shared above by D.E.C. Belkhait, and I thank him very much for suggesting it :).
If you decided to use it, please let me know in case something is not clear.
I'm still working on improving the code and clarifying its description.
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An integration of fuzzy logic for the development of a fuzzy control law of the access control system. Indeed, the goal of ensuring a constant flow of road traffic where we present a approach based on fuzzy logic allowing to have a reduced representation of the space of dimension 4 in a space of dimension 1 ensuring the regulation of traffic on the one hand, and the analysis system on the other.
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yes, provided the variables involved can be express as fuzzy sets,
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Hi . Im trying to design a LQR controller for the system below. but I don't know where to put the LQR Gain Block in the system . I know I have to remove the Fuzzy Controller Block and Replace it with LQR Gain , but I don't know how to do that , I mean I guess I need an Observable Matrix for that? can anyone help me pls ?
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Thanks , But none of them use Observer in their design. and My Main problem is that I dont know the output or the input of this model Im working on ! so I dont know where to put LQR Gain and Observer Gain in this !!!
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Basically I am working on Lorenz Attractor and I want to design an intelligent controller based on Fuzzy Logic.
Kindly help.
Thanyou in advance.
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Dear Saikat,
Also i suggest you to see links and attached files in topic.
-Chaos Control Using Fuzzy Controllers (Mamdani Model) - Springer Link
-A controller design used in Lorenz synchronization chaotic system for ...
-Fuzzy Chaotic Systems: Modeling, Control, and Applications
-Design of an adaptive fuzzy model based controller for chaotic ...
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Hi!
I have had this question, ever since I started my research in adaptive fuzzy controllers and that is--- How shall I construct the fuzzy rule to approximate the unknown dynamics- f(x) and g(x) in the dynamical system. If I start off with lets say 3 MFs to approximate the dynamics and if lets say I have some 9 states that completely describe the system dynamics, then, do I need to take all the possible combinations i.e 3^9 as number of fuzzy rules? Or just 3? Or any number between 3 an 3^9? What should be the optimum number of fuzzy rules to approximate the unknown dynamics?
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I suggest using fuzzy clestering.
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I am using fuzzy logic to help decision-makers to get "quickly" and reliable decisions. I have collected many projects and I am interested on 12 parameters. So Finally my system has 12 inputs, each one has 3 membership functions(MFs), and one output with 4 MFs.
But I have a problem regarding the Inference system, i.e. If-Then-Rules. My parameters have a solid Relationship between them, so I think that I Don't have to consider all possible combination ( 3^12) but I have to make sure that my system got a good training and then I can trust him.
Before talking about the testing the system with a sall dataset, let's talk about the way I can consider all possible If then rules. should I come bach to each project and according to each one I see on which membership it belongs, or I use Simply the parameters ranges that I already realised and build my If-then-rules according to that?
One more question relating to unsuccessful projects. how could I consider these information (example: when a was low and b was Med and ….. Then the project X was insuccessful, Can I use it like this:
If a is Low and b is Med and …. Then output is not X ?)
I will more than happy f you share with me your experience so I can adapt it to my problem and act accordingly.
Thank you, and I am wainting for your interactions.
King Regards,
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>should I come bach to each project and according to each one I see on >which membership it belongs, or I use Simply the parameters ranges that I >already realised and build my If-then-rules according to that?
If you are using MATLAB then when you view the output. It already highlights the execution of rules and values on membership functions which depend on the data value passed by you and the way your rules have executed. The design of rules and membership functions depends on the
range of your data, results obtained from existing techniques, Experts opinion...
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Hi! I have a system that loosely looks like this-
$\dot{x}_{1}=f_{1}(x_{1},x_{2},x_{3},x_{4})$,
$\dot{x}_{2}=f_{2}(x_{1},x_{2},x_{3},x_{4})$,
$\dot{x}_{3}=x_{4}$,
$\dot{x}_{4}=f_{4}(x_{1},x_{2},x_{3},x_{4})+bu_{1}$,
$y=x_{3}$,
I am designing a direct fuzzy adaptive controller to control the state x3. I wish to know what should be inputs to the fuzzy system that will approximate the ideal controller? Is it going to be all the states i.e $x_{1},x_{2},x_{3},x_{4}$ or $e,\dot{e}$? And finally what kind of adaptive law will ensure that the error is driven to zero. In my real system, I have got 9 states, and the state that I am interested in controlling has a relative degree of two. So, Shall I take all the states as input to my adaptive fuzzy controller? If I choose that, then will it not be exhorbitantly computationally expensive- considering the fact that there are 3 MFs per input-- resulting in $3^{9}$ rules? Kindly provide your inputs. Thanks in advance.
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Question #1:
One possibility is due to poor approximation. Have you really compared the output of the approximated function with the output of the actual function? If the approximation error is large or deviating from zero, there could be various reasons.
Question #2:
Another possibility is that the performance of the baseline control (nonlinear state feedback) is poor, slow, or sluggish. Have you really compared the results of the adaptive control with the results of the baseline control with known functions f1 & f2?
Question #3:
Have you really checked if the residual is sufficiently compensated by robustifying term in the adaptive control? Please check the V' signal, where V' is the time derivative of Lyapunov function.
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I am working on a problem with many conditions (say 40). If I write the membership function for two inputs; how can I create own fuzzy output function. Is it possible with the fuzzy toolbox?
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The process is direct. You can use the simulink in MATLAB. Define the membership function (MF) and number of input to output to be considered. Alternatively, you can create your output space by properly defining and arranging your dataset taking into consideration the amount of output MF link. Then import from workspace. Please look out for good materials online. Youtube info. will be helpful.
Regards
Modestus
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I am working on Simulink Model of 8DOF semi active suspension quarter car model with passenger. The MR Bouc Wen Model is used in the model which is controlled by Fuzzy controller with 2 input (sprung mass displacement, sprung mass velocity) and 1 output (Voltage).
I want to optimize Fuzzy rules and Fuzzy Membership function by Particle Swarm Optimization techniques. The Objective Function is Minimization of Sprung Mass Displacement.
I am looking for Matlab Codes for the same. How can I call Simulink output as Objective function in Coding?
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Dear Pankaj,
I suggest you to see links and attached files in topic.
- Applying metaheuristic optimization methods to ... - Tubitak Journals
- An Optimal Fuzzy Logic Guidance Law using Particle ... - CiteSeerX
- Optimization of a Fuzzy-Logic-Control-Based MPPT Algorithm ... - MDPI
- Energy Consumption Optimization and User Comfort ... - MDPI
- Automatic Fuzzy Membership Function Tuning Using the ... - IEEE Xplore
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I'm working on a implementation of a Fuzzy controller in a FPGA board, I know that a part of the controller is the inference and I need a matriz for that, so the question is, How can I implement that part in VHDL.
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Thanks a lot, I'm going to check the info. Good day.
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I would like to create an Adaptive Fuzzy Controller which its output membership functions will change every time accoırding to algorithm that I will code. Can you please tell me if it is possible to do in simulink environment where I can add algorithms to my fuzzy controller and make it adaptive.
Fozzy Logic Toolbox in Matlab/ Simulink does not have the option of doing so .
Best
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you need to write m-code for the fuzzy controller not to use the toolbox ready block. so you can have the flexibility to add the adaptive algorithm within the fuzzy code.
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I want fuzzy logic controller design theoretically and in MATLAB simulink and programming  any one have that material?especially for designing uavs and quadrotors
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You may try to design your own FLC and optimize the MFs like this paper posted on https://goo.gl/HrFxnY
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What will be a successful mixture? for what end? could you please steer me towards some good references that have applications, and solution by approximate analytical methods?
Many thanks and best regards
Sarmad.
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Presents a systematic treatment of fuzzy fractional differential equations as well as newly developed computational methods to model uncertain physical problems
Complete with comprehensive results and solutions, Fuzzy Arbitrary Order System: Fuzzy Fractional Differential Equations and Applications details newly developed methods of fuzzy computational techniquesneeded to model solve uncertainty. Fuzzy differential equations are solved via various analytical andnumerical methodologies, and this book presents their importance for problem solving, prototypeengineering design, and systems testing in uncertain environments.
In recent years, modeling of differential equations for arbitrary and fractional order systems has been increasing in its applicability, and as such, the authors feature examples from a variety of disciplines to illustrate the practicality and importance of the methods within physics, applied mathematics, engineering, and chemistry, to name a few. The fundamentals of fractional differential equations and the basic preliminaries of fuzzy fractional differential equations are first introduced, followed by numerical solutions, comparisons of various methods, and simulated results. In addition, fuzzy ordinary, partial, linear, and nonlinear fractional differential equations are addressed to solve uncertainty in physical systems. In addition, this book features:
Basic preliminaries of fuzzy set theory, an introduction of fuzzy arbitrary order differential equations, and various analytical and numerical procedures for solving associated problems
Coverage on a variety of fuzzy fractional differential equations including structural, diffusion, and chemical problems as well as heat equations and biomathematical applications
Discussions on how to model physical problems in terms of nonprobabilistic methods and provides systematic coverage of fuzzy fractional differential equations and its applications
Uncertainties in systems and processes with a fuzzy concept
Fuzzy Arbitrary Order System: Fuzzy Fractional Differential Equations and Applications is an ideal resource for practitioners, researchers, and academicians in applied mathematics, physics, biology, engineering, computer science, and chemistry who need to model uncertain physical phenomena and problems. The book is appropriate for graduate-level courses on fractional differential equations for students majoring in applied mathematics, engineering, physics, and computer science.
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We want do develop a device which can intimate us if blood pressure increases or decreases beyond the prescribed range. This device should we wearable like a bangle. 
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It is challenging to track a multitude of changes in physiology over time. Heat, Cold, blood volume (fluids), food, drinks, stress, relaxation, fear, exercise etc. all act as inputs to a continuously changing heart rate, stroke volume & vascular resistance. The body has many control points as it aims to regulate perfusion of cells on an almost beat to beat basis. It is very difficult to track changes in blood pressure over more than a few minutes with any degree of accuracy.  
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I want analyse the stability of chaotic systems and design a controller for such systems. 
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A book which deal with more general nonlinearities is the one written by Drainkov and Hellendorn: http://www.springer.com/gp/book/9783540606918.
With all respect, but although LMI approach is very nice, it has some drawbacks. I actually like it but you may wish to see the book I told you about,
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consider a boost converter with fuzzy controller.
what is the adv of taking 3,6,9 membership functions?
will that cause complexity in hardware implementation (say in dsPIC30f)
Considering the practical and theoretical approaches, how many membership function should be taken? 
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Increasing Memberships causes to have an accurate and high quality fuzzy system
but it depends on an expert person's knowledge. maybe you need to have 1 membership or more...
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I want to know about the present state of the art in the field of fuzzy logic controllers. I have with me only some surveys which spoke about the researches that were conducted till 2007. I am in need of some survey papers that can help me get an idea of the research work that has been carried out after 2007 and till the present date. Please help.
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This type of algorithm (Takagi-Sugeno fuzzy)  is talent to deal with MIMO plants that possess lag time, big inertia and uncertainty and can be deemed as one of the most important components of intelligent buildings
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Dear Raad Z. Homod,
I suggest for you look at link, attach files and publication in topics.
-comparative study of fuzzy control, neural network control ... - CiteSeerX
-ANFIS: Adaptive Neuro-Fuzzy Inference System- A ... - Semantic Scholar
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Is there any other ideas than "probability theory" to derive the intervals from the responses in intervall-type Type-2 Takagi-Sugeno Systems?
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Dear Prof. Mohamed-Mourad Lafifi, I would like to thank you for your valuble information and time.
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what methods are available to identify intervall-type Type-2 Takagi-Sugeno Systems and which one is better and why?
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Dear Prof. Mohamed-Mourad Lafifi, I would like to thank you for your valuble information and time.
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I must write Sugeno type fuzzy controller with .m script. How can I write without using fuzzy toolbox? Where can I find an example about it?
Thanks... 
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Hi Dr. Öztürk,
You can certainly find some examples related to Fuzzy Logic Systems in the links given below. However, we are unsure of the real reasons you want to build a Sugeno-type fuzzy controller with the m-script. If the output of the m-scripted fuzzy inference system (FIS) is the same as the output of the FIS built using the Fuzzy Logic Toolbox™ GUI tool, then we don't see any motivation for doing so. 
If you want to build a FIS using Custom Membership Functions, other than using the standard functions (triangular, trapezoidal, bell, gaussian, etc) in the toolbox, open the 4th link. 
Perhaps you should try building a simple Sugeno FIS with the Fuzzy Logic Toolbox™ first, unless you want to build an Adaptive Fuzzy Controller, or a Genetic Algorithm optimized Fuzzy Controller, where the shapes of the input membership functions, output singleton locations and the IF-THEN rules are time-varying.
Good luck!
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We have to control the amount of water flow as well as any advice how to make it Intelligent?
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Hi Mr. Guin,
I think the point is probably not about making the fire sprinkler system “intelligent”. If you are a designing a cost-effective fire sprinkler system, then it is about optimization. 
By optimization, it means that the controller is capable of effectively regulating the amount of water to any flow rate desired through the Flow Control Valves and Sprinkler Valves corresponding to the level of signals in the fire detection system in the shortest time possible (talking about saving lives). When the flow optimization is achieved, the number of sprinklers can be reduced, and thus leading to cost reduction.
Having a good knowledge of the water flow process to be controlled is beneficial, and in firefighting, it is crucial. As you probably already know that the flow through the valve is turbulent and is nonlinearly related to the hydraulic head of water, then the conventional linear PID control system is insufficient. 
Knowing this shortcoming allows you to tap into the power of using Fuzzy Logic Controllers. The fuzzy controller can accommodate multiple inputs and multiple outputs (MIMO) and the control strategy consists of heuristic If–Then rules, and tuning flexibility with varying the degree of membership functions. 
Your first step should be designing a linear Fuzzy controller that performs as good as the existing PID controller for the water flow system. Then, apply nonlinearities to the Fuzzy controller by modifying the rules, or reshaping the membership functions (e.g., shifting the center points and widths of the membership functions, and replacing triMF with gbellMF, gaussMF, etc.), or both.
If you are dealing with a Type-2 Fuzzy controller, then you need to define the distribution of uncertainties denoted by the footprint of uncertainty (FOU).
Good luck!
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fuzzy
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Hi Dr. Sandeep,
Assuming that your conventional PID-tuned controller has done a good job in regulating the speed of the SVPWM Inverter Fed Induction Motor Drive, you can generally do better with a Fuzzy PID controller by introducing the some “good nonlinearities” in the system via amendment of the IF-THEN Rules and shaping of the Membership Functions based on the expertise knowledge of a seasoned Engineer in Power Electronics and Motor Drives.
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Actually i'm working on a wind system, now i want to replace the PI controller with Fuzzy Logic Controller for MPPT strategy, but i have a problem defining the right gains to obtain some good results.
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Hi Ms. Ibtissam,
Here are additional remarks on the design of Fuzzy PI controller. There are several variants of a Fuzzy PI controller. The approach in my previous post is suitable for one variant (with the linear PI gains fixed), while other variants may require adjustments on the Fuzzy gains.
Could you identify the type of variant that you use to replace the Linear PI controller? 
Reshaping the fuzzy control surface (from linear to nonlinear) is necessary in order to improve the response of the closed-loop system. This can be done either by
  • modifying the If-Then rules,
  • gradually altering the shapes of the membership functions, or
  • increasing the range of operation within the universe.
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fuzzy speed controller
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At first I agree with previous recomendations about fuzzy parameters.
At the same time I"d recomend to use a PI controller in inner loop (current controller)
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Hello, I'm looking for some practical examples of MPC algorithm i.e. procedures step by step with the practical background. Theory is well documented, but examples I found are full of gaps, which made them not so usefull.
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Dear Stawomir,
I suggest to you links and attached files in topics.
-Dynamic Modeling, Predictive Control and Performance Monitoring: A ...
-Model Predictive Control of Wind Energy Conversion Systems
-Model Predictive Control for Nonlinear Continuous-Time Systems with ...
-Model Predictive Control of Wastewater Systems
--Dynamics and Control of Process Systems 2004
Best regards
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I want to create a membership function for the probability distribution (generated from statistical data) of the remaining fatigue life. Can anybody guide me on how to do so? I have found few papers on internet but most of these seem to confuse me rather than helping me. It would be great if somebody could guide me in the aforementioned matter. Thanks.
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Thanks a lot Dr. Mauris.
Best Regards,
Arvind Keprate
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someone wants to implement fuzzy logic in simulink, what steps should he follow? Thanks in advance!
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You can implement the fuzzy logic in GUI by using the Fuzzy Logic Toolbox and export you design in the MATLAB workspace. Then call the workspace function in simulink via the fuzzy logic controller block.
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I m working on use of fuzzy logic in water quality indezing...
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Please check this book: 
T.J. Ross, Fuzzy Logic with Engineering Applications, 3ed, John Wiley & Sons, 2010”
Also the following Q&A in RG:
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Hi,
I am working on to design closed loop blood pressure control system, for this firstly I developed fuzzy rule set, but for increasing the efficiency of controller I plan to develop  adaptive fuzzy control in Matlab.
So, for this I choose  ANFIS edditor module in Matlab. For this module training data set and testing data set are required to develop a rule. 
But I don't know what is the structure of data set or data set should contain which type of information for training purpose.
I am looking for any example data set to training or testing  in ANFIS.
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Dear Naira, hello. I'd like to explore the possibility of doing joint research in fuzzy optimization. I have worked with fuzzy control for mechanical systems but I'd lke to improve this.
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Hello Ricardo. I see. Good idea. I hope someone will step in to hammer out a joint project with you on Fuzzy Optimization.  Unfortunately, I am not expert in that area.  Best wishes. Abdel
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i am working on a simulink model and need to normalise the output values to -1 to 1 so that i can imply fuzzy controller easily. i am working in simulink environment.
Regards:
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if I understand your question well, you have to set the output membership function to [-1,1] then you can use a K factor to control the dynamic response.
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I need to analysis some data on stability model using Ebernert and Russell, Shukla and other relevant ones
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@Gunter Laux. Sir, i have try to make use of this information but its difficult to get the information right. All effort in using the procedure laid down in this paper is not working may be am the one that is making mistake in interpreting the article content
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Hello all,
My system is MIMO system I want to implement fuzzy controller for this system, but I have digital inputs and digital outputs . Any body have an idea how is the shape of the fuzzy memberships should be to manipulate the digital behavior of these digital input and outputs.
Regards
MAnsour
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Thanks all
Simply i want to get digital output from the fuzzy controller 0 or 1, any body face this problem before? 
Please note I dont take about Digital Implementation of Fuzzy Logic Controller 
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i am trying to use fuzzy cognitive map to model a system, so i just start trying the available tools to do so, one of these tool is FCM tool under matlab, where you fill the connection matrix and also number of concepts and the initial state vector to initials the map. the problem when i use sigmoid  function as threshold it gives some result where the system should converge and at stable state, whenever i change the state vector for the initial value the result always stay the same which is not make sense? if any one has use this tool and can help to explain what went wrong that will be highly appreciated.
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I would like to ask you to share with your experiences related to fuzzy supervisory control. I think about such a algorithm which is able to change parameters of a classical PID controller, based on a human experience due to plant's dynamics variations, disturbances etc.
I wonder if such a algorithm would be able to make a control process more robust.
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Dear Olof, my question was simply related to the fact that I am programmer of industrial several controllers and some of them e.g. controllers from Bernecker&Rainer provide a lot of opportunities for practitioners. I agree that sometimes faster and simpler is to find heuristic algorithm and implement it. 
But sometimes as a scientist I would like to test some theoretically developed solution, simply to proof its efficiency or simply... throw it away as a useless for the industry (to sophisticated or not so nice than in a related publication).
I find several publications related to the fuzzy supervisors for PID e.g. Design and implementation of a fuzzy supervisor for on-line
compensation of nonlinearities: An instability avoidance module (Engineering Applications of Artificial Intelligence 19 (2006) 323–333) and after that I decided to do sth like information mining according to fuzzy supervisors.
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What microprocessor should I choose if I want to implement  PID or fuzzy control? Arduino? Raspberry Pi? Any suggestions?
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Both of the boards are capable. But, you can conveniently prepare an arduino board for these purposes. 
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i designed a FLC with 2 inputs and 1 output. the range of inputs are [0 1] and [0 20] and output's range is [0.008 0.01]. when i run it in my simulation the value of output is zero means flc gives  a zero value for output while the range of output starts at 0.008. assuming i designed flc inappropriately. Is getting  zero value logic? my inputs are in the own ranges. 
why do i get this result?
regards
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Thanks a lot dear Ning. I will read them surely.
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i am working on fault detection of a system and using fuzzy logic for decision and detection. but issue is i have a variable and fluctuating residual signal , now i have to take its limits to set a rule based on the magnitude of the residual, but its is varying and once it is + valued and other time negative  like a sinusiodal sine wave, now i should do for smoothing it and find the accurate magnitude so i can assign values to my fuzzy controller? 
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Hi,
first,the input of your bloc fuzzy in Simulink is the error and the dérivative of error ,the input should be normalized to 1,and the output is the commande.
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See above
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fuzzy logic (mamdani and sugeno) With bang bang controller.
It is suitable for simple systems
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I'm working on a laboratory Helicopter model (from HUMUSOFT company) and I've designed a TS fuzzy observer-based controller for it and I want to implement it.At first a PID controller performs then fuzzy controller, but fuzzy controller produces a very large signal output that is out of range of machine. I want to switch between these two controllers in machine range.
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Hi,
Well, both controllers are not assuming the explicit system dynamics (considering no system is really linear), so they can be considered more "regulators" than the "controllers".
Since both methods you mention above put more emphasis on the measurements/estimations of the input/output (or could be also the state) than the parameters of the system dynamics, and considering that using a "hybrid" type control is more problematic in sense of "stability" than the tracking performance; then I would try to find a scheme that handles the transition phase by observing input and output of the system. Clearly, you would like to have a small input for a small output, so from the intuition, make sure that you are switching controllers when your system is close to its equilibrium, or at least in the region of attraction. A more sophisticated way would be using Inout/Output Stability tools, e.g. using L-norms, or depending on your system maybe Input-State Stability (ISS).
Cheers,
Burak
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I have an online parameter estimation based on recursive least-square method to approximate the model given I/O observation data. How can I link this model with the adaptive PID control law, considering that neither pole placement technique nor Model Reference Adaptive control can be implemented because the system is too complex to model ? 
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(For some reason, my answer did not go. I hope it will no suddenly show twice)
First of all (except for  strictly official occasions), I am just Itzhak for all, no need for Prof., Dr., Mr., or Sir.  :-)
Now, we start talking. Still, in the same spirit of "no general solution for the general problem," it will take a while to get what you want.
BTW "what you want," you write:
>I don't know either the desired behavior of the system, or a model reference to follow. I only have a constraint on the output that must converge to the constant reference signal.
If you want to control something you must know what you want it to do. I don't mean the behavior of all its state variables, or anything like that. However, if the output now converges to what you want, should it do it in 1 msec, 1 minute, 1 hour? If you do know, then build a simple model, say a good 2nd order system which does what you want in response to the step input. Then, supply the step input to the model and supply the model output as the new input to the plant.
Unlike the standard MRAC which may require a pretty complex adaptive controller for any other than very low order systems, the techniques that i called Simple Adaptive Control (SAC) does not assume that the Plant is sooo unknown that you cannot do anything. You start with something that somewhat "works" and then adding the simple adaptive control make it better and also maintains performance in spite of parameter and other plant changes.
If you say that your nominal Plant is stable and converges, then first of all see how it behaves in response to the new input. Don't be disappointed by the new delay in its response. we will take care of it.
I saw you started following me on RG. Maybe you try to get "Classical and Simple Adaptive Control..." It pretty much describes how to deal in a similar case.
In any case, start and see how it works and we will talk again.
Salute,
Itzhak
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   In Layer 2 of ANFIS sugeno type model, it serves to evoke firing-strength by multiplying each input signal. why the firing strength need to be normalised?
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Thank you for your reply sir....More useful materials
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The system is nonlinear described by a set of 8 ODEs (8 states). Two discontinuous functions (jump discontinuity) are present in the first state equation. Can any one suggest the method to design a TS fuzzy model for such system?
dx1/dt = -x1.x3 + k12.x2 + EGP(1 - x5) - F - Fr + u1
dx2/dt = x1.x3 - k12.x2 - x2.x4
dx3/dt = -ka1.x3 + kb1.x6
dx4/dt = -ka1.x4 + kb1.x6
dx5/dt = -ka1.x5 + kb1.x6
dx6/dt = -ke.x6 + ki.x7
dx7/dt = -ki.x7 + ki.x8
dx8/dt = -ki.x8 + u2
states: [x1 x2 x3 x4 x5 x6 x7 x8]
parameters: [k12 EGP ka1 ka2 ka3 kb1 kb2 kb3 ki ke]
dis-continuous functions: [1] Fr = 0.003(x1-9), when x1>=9
                                              Fr = 0, [otherwise]
                                         [2] F = 0.97 , when x1>=4.5
                                              F = 0.97.x1/4.5  [otherwise]
Q/ How to take the discontinuous functions as premise variables of fuzzy model? 
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Dear Anirudh,
One researcher who has worked in this field and has achieved convincing results of K. Mehran’s. Here files attached on this researcher and some other researcher.
Best regards
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If I have designed a fuzzy inference system (say controller) using Fuzzy Logic Toolbox in Simulink. Now Based on some performance criteria, I need to update/modify the existing structure of fuzzy controller, say, Rule base, scaling factors and membership functions.
How do I do so in Simulink? Lets say, I have implemented the algorithm in a S-function/Embeded Mat;ab Function block in Simulink. now, I want to access the rule base and MFs and update them online without stopping the simulation.
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@Victor Vladareanu 
Thank you very much for your kindness. I will let you know after I try to implement it.
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I would be grateful if you could send me the download link of it, because I could not find it via internet while I really need it. There is interval type2 fuzzy toolbox but I could not find Generalized fuzzy toolbox.
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Dear Vitalii Pertsevyi
Thanks for your response
The first attachment does not support Generalized type2 fuzzy system. While the second attachment supports this fuzzy system, it does not have simulink block to have outputs for control aims. Do you know how to have outputs of this toolbox(difuzzificated output) in matlab?
I appreciate your time and response
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I have read a lot theory about Self Organizing Fuzzy control from Internet. But I am still not completely able to understand its theory and implementation.
I have attached one of the best document I could find on Self Organizing Fuzzy controller from internet.
Please can anybody share the implementation for self organizing fuzzy? if anybody has developed any control logic using this technique.  
Thanks in advance :)
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I am very new to fuzzy logic. And I read a lot of examples over the internet. But I could not understand one particular example where only non overlapping member fuctions were used (which I find very uncommon). So I would like to have a better understanding in this aspect.
and one more request.
I am trying the implemetation for fuzzy controller in C. So if there is any good material to read I would appreciate if you can suggest.
Thank You 
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If you are using only one fuzzy set for whole universe of discourse, then there is no question of overlapping because you are denying the possibility of existence of more than one fuzzy set. If you are using two fuzzy sets e.g. person of age 5-10 (Child) 15-20 (adult), again there is no question of overlapping. But if you are using three fuzzy sets 5-10 (Child), 10-15 (Young) and 15-20 (adult), there there must overlapping to deal that age of few persons that may belong to both child as well as yong. And young as well as adult.
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 Does connecting two fuzzy logic controllers one for speed and another for current bring about any improvement in the performance of the  DC motor? I have used fuzzy logic controller for speed control and a PI controller for current control . When i connect another fuzzy logic controller for current control in series with the already existing fuzzy logic controller output is not correct. I am not able to understand why.
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It is not possible to improve performance of the fuzzy controller connecting in series. You may connect parallel mode for compensation of multiple variable.  Or may be used in cascade mode where output of one variable can be taken as set point of another to improve performance in primary and secondary control mode.
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Here is the function.
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Any PD controller will stabilize the system. The closed loop natural frequency will be determined by the proportional gain (P-term) and the damping by the rate feedback gain (D-term). PSO is overkill. But if you really want to use a search method, then define the cost index to be
     \int_0^\infty (e^2+u^2) dt
and you will get reasonable gains. You can then compare your result to that from the LQR method.