MATLAB: How to log the fired strength of rules in a fuzzy Inference System (FIS) at each simulation step in Fuzzy Logic Toolbox 2.2.8 (R2008b)

Question

I would like to know if there is a provision for logging the firing stength of each rule in an FIS at each step in a simulation.

This feature will enable me to tune the Fuzzy Controller more easily.

Answer 1

There is no direct way to log the firing strength of the rules in an FIS at each step in a simulation in fuzzy Logic Toolbox 2.2.8 (R2008b).

As a workaround, create a scope and log the data from the appropriate block (since the 'Fuzzy Controller with Rule Viewer' block is built from Simulink blocks). Here is a simple illustration of how this can be done:

1. Execute 'sltankrule' - This opens up a DEMO model called SLTANK rule that has a 'Fuzzy Controller with RuleViewer' block.

2. Navigate to the FIS Wizard subsystem (Right click on 'Fuzzy Controller with ruleViewer' and select 'Look under mask', then right-click on 'Fuzzy Logic Controller' and select 'Look under mask', then right-click on 'FIS Wizard' and select 'Look under mask')

3. Then, right click on the second output of each 'Rule' block and select 'Create and Connect Viewer' --> 'Simulink' --> 'Scope'.

4. Open the scope property dialog (second icon from the left on the Viewer: Scope toolbar) and select the 'History' tab. There, make sure to check the 'Save to model signal logging object (logsout)'.

5. Run the model for say 20 seconds and pause/stop model

6. The required signals are logged in the workspace under the 'logsout' object. You can access the data as follows:

logsout.ScopeData.axes1.SL_Rule12.Data