Fuzzy Logic Controller

Fuzzy logic controller block in IDR BLOK
FUZZY block can be used in IDR BLOK diagram the same as any other block. FUZZY block is not available in the standard IDR BLOK package but as an optional addition.

IDR BLOK Fuzzy block characteristics
FLC type:                                      Sugeno 0 order
Number of inputs:                           1 or 2
Number of outputs:                         1
Number of segments for each input: 3 to 7
Shape of segments:                        triangular
Maximum input range:                     -10000 - +10000
Output range:                                 -10000 - +10000

Fuzzy Logic Controller Designing Tool
The FLC editor enables the design and testing of fuzzy logic controllers
implemented by FUZZY blocks in an IDR BLOK program. Testing can also be
performed by simulation during the design phase or in IDR BLOK ONLINE mode.
Parameters can be changed interactively in ONLINE mode. These capabilities
provide for easy and fast development of fuzzy logic controllers.

Features
FLC settings are entered by an editor, designed specially for FLCs used
in IDR BLOK. These settings include FLC structure, segments (membership functions) and knowledge base (rules). The editor is intended to enable setting the FLC’s many parameters in a user friendly manner.

The fuzzy editor window contains the three dimensional FLC output characteristic. It also contains menus and a toolbar, which are used to set FLC parameters.

When this window is closed, control is returned to IDRBLOK schematic. All other
editor windows can be opened and closed as needed.

During the FLC design its structure must be defined, which means the number of inputs, number of segments for each input fuzzy variable and ranges of the crisp input values. These data affect FLC operation.

The FLC editor enables the setting of parameters for the input and output variables, segments (membership grades), fuzzy rules (IF statements and truth table) in specifically designed separate windows.

Displaying results
The main application window is used to show the final result of FLC design - a three dimensional output characteristic - and to control the rest of the fuzzy editor through the menu options.

3D output characteristic
This characteristic shows the relationship between inputs and output of the FLC. In this way the designer can see whether the intended results are achieved. All changes to the FLC settings are shown immediately. The characteristic can be rotated to different points of view (around the horizontal and the Z-axis). The current values of the inputs position the cross mark displayed on the characteristic.

2D output characteristic
The 3D characteristic gives the best impression on FLC behavior, but unfortunately there are limitations in displaying it on a 2D computer screen. The characteristic can be observed in relation to one input from the top view by selecting the 2D view option.

This mode also makes it possible to observe FLC behavior more precisely. By moving the cross mark by mouse, the input values to the FLC change and its output is written in the top left corner of the window. Sliders and edit fields in the Rule editor are updated automatically.

Bar graph
This option opens a window which is intended for testing, not design. Each rule is represented by three bars in a row. The bars in the left column show the degree of membership grades for the first input value, bars in the second column show the degree of membership grades for the second input value, while the right column shows rule output. Rule order is the same as in the IF statements window. Rules can also be determined from the text in the bars, where segment names are written.

FLC test - simulation
After the FLC is designed or during debugging it is useful to see the FLC output for specific inputs. To enable detailed analysis of the FLC behaviour, a simulation capability is provided within the FLC design environment. FLC inputs can be set to any value within the input range and the FLC output observed.

Online mode
When running the FLC editor in ONLINE mode, the behavior of the program is the same. If you change a FLC setting in the editor, this change is automatically sent to the PLC. However, FLC input values can not be changed manually as in edit mode, because they are updated from the PLC.

IDR BLOK Fuzzy Logic Controller Designing Tool - English manual (PDF, 166 KB)