Is it possible to add entry, during and exit actions to states that include differential equations?

I am trying to connect three states in Simulink out of which 2 contain differential equations (first one without, second and third with diff equation). However, I cannot put entry, during or exit commands for the middle state - it always gives an error saying the state doesn't support these actions. How can I get this to work?

Answer 1

[Purvaja]

Hey @Katarina Kovacevic,

I faced the same issue and found that when a Simulink-based state (i.e., a state that contains a Simulink subsystem or differential equation block) is used within a Stateflow chart, Stateflow prohibits adding entry, during, or exit actions directly on that state, that’s why we were encountering the error.

You can try this workaround:

Wrap the Simulink state inside an otherwise empty parent Stateflow state, and place your entry, during, or exit actions in that parent. Inside the parent, you can have a default transition going to the Simulink-based child state (but ensure that the initialisation of variables are taken care of in this case). This approach allows you to attach the actions where needed without errors.

I tried a dummy example with 3 states as you intended.

As you can see above, S1 has no ODEs, while S2 and S3 contain differential equations. Here, "u" is input variable and "x" & "y" are output variables. Ensure that their "Update Method" parameter is set to "continuous".

I came up with this workaround with the help of below answer on MATLAB Answers Community:

https://www.mathworks.com/matlabcentral/answers/1574143-how-do-i-add-entry-and-exit-actions-to-a-simulink-subsystem-inside-of-a-stateflow-chart

Hope this resolves your issue.