Feedback in QtFuzzyLite 6

[Unknown]

Hello, I used QtFuzzyLite 6 to design a controller. Now I want to test it in a simulation. Is there a possibility to design somthing like a feedback loop so that the controller output influences the controller input values for the next simulation step?
What about the option of Client/Server communication via TCP/IP? May it be used for the described purpose? Does somebody have experiences how to use this way of data exchange for a controller simulation?
Thanks a lot.

[Juan Rada-Vilela (admin)]

Hi Joerg,

thank you for your interesting questions.

It would be better if you provide an example of what you are trying to achieve.

For what I understand, it seems to me that you may want to use output variables as antecedents in the rules, although this does not refer to the next simulation step (t+1). Consider the example “SimpleDimmerInverse”, where the output of Power is computed and used in the same simulation step:

#File: /fuzzylite/examples/mamdani/SimpleDimmerInverse.fll
Engine: SimpleDimmerInverse
InputVariable: Ambient
  enabled: true
  range: 0.000 1.000
  lock-range: false
  term: DARK Triangle 0.000 0.250 0.500
  term: MEDIUM Triangle 0.250 0.500 0.750
  term: BRIGHT Triangle 0.500 0.750 1.000
OutputVariable: Power
  enabled: true
  range: 0.000 1.000
  lock-range: false
  aggregation: Maximum
  defuzzifier: Centroid 200
  default: nan
  lock-previous: false
  term: LOW Triangle 0.000 0.250 0.500
  term: MEDIUM Triangle 0.250 0.500 0.750
  term: HIGH Triangle 0.500 0.750 1.000
OutputVariable: InversePower
  enabled: true
  range: 0.000 1.000
  lock-range: false
  aggregation: Maximum
  defuzzifier: Centroid 500
  default: nan
  lock-previous: false
  term: LOW Cosine 0.200 0.500
  term: MEDIUM Cosine 0.500 0.500
  term: HIGH Cosine 0.800 0.500
RuleBlock: 
  enabled: true
  conjunction: none
  disjunction: none
  implication: Minimum
  activation: General
  rule: if Ambient is DARK then Power is HIGH
  rule: if Ambient is MEDIUM then Power is MEDIUM
  rule: if Ambient is BRIGHT then Power is LOW
  rule: if Power is LOW then InversePower is HIGH
  rule: if Power is MEDIUM then InversePower is MEDIUM
  rule: if Power is HIGH then InversePower is LOW

Alternatively, you could (1) create your own activation method, or (2) create your own way to process the engine. For (1), you could create an activation method that stores the output values at (t-1), computes the current outputs at (t), and changes the current outputs according to (t-1). For (2), you do not execute Engine::process(), but instead create a method of your own to do the same as in (1). You can take a look at what Engine::process() does for an idea. In cases (1) and (2), you will not be able to see the simulation in QtFuzzyLite, though.

If you provide a more specific example of what you are trying to achieve, there may be other solutions.

Cheers.

[Unknown]

Dear Juan,
thank you very much for your fast and kind reply. I was some days out of the office so I can reply only now. Sorry for the incomplete description of my problem.
A little bit simplified my engine is a heating unit in a room. Output of the controller is the heater power. But the heater should not only stabilize the current room temperature in a certain interval, it should also take into account the expected weather conditions of tomorrow and the expected tomorrow energy costs.
So for my fuzzy control, which I would like to use for a time step simulation, I have two different kinds of input values. First, external parameters (weather – W, costs – C) which I can provide to the controller e.g. as a file in the QtFuzzyLite Simulation tool.
Second, the room temperature T. I imagine the calculation as follows:
For the values Tn, Wn and Cn (at time n) the fuzzy controller calculates the heater power Pn. This Pn changes the room temperature to Tn+1 according to a room model. Together with Wn+1 and Cn+1 (from the file) this Tn+1 should be the input for the next controller calculation.
Is it possible to solve this problem using only QtFuzzyLite-Tools? For example, can I use the file monitor option of the simulation tool? How does it work? Is there an interface to make Pn accessible for external software?
I’m not very familiar with C++ programming. Up to now all my attempts to compile a FuzzyLite project with VS2017 failed…
Many thanks and best regards
Joerg

[Juan Rada-Vilela (admin)]

Hi,

thank you for your post and interesting questions.

At the moment, unfortunately, it is not possible to do what you suggest with only QtFuzzyLite, but it should not be too difficult to do using fuzzylite for C++ or jfuzzylite for Java.

I have not tried compiling fuzzylite with VS2017, but I assume that it is not different from VS2015. Please, have a read at the updated compile instructions for fuzzylite 6 at https://github.com/fuzzylite/fuzzylite#compile-link-and-execute Also, please have a look at the sample project available at https://github.com/fuzzylite/fuzzylite/tree/release/examples/application . You should take a look at the definitions made in the CMakeList file.

[Unknown]

Hi Juan,
thank you for your answer. I will work through the compile instructions and come back with detailed questions if required.
Best regards
Joerg

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