Running external c-code function in MTK model

Specific Domains Modelling & Simulations
1

Hi community,

I am new to Julia and in particular MTK.
My goal is to simulate a battery cell and couple it with external C-code to run an extended Kalman filter for SOC estimation at a fixed sampling rate.

Somehow this kind of problem does not seem to be something many people deal with in Julia, at least documentation is very limited here. I guess FMU would be a possibility. However, the FMI.jl package hasn’t beed updated for a while and so far it does not support array inputs/outputs (which I ultimately need). Even then, how would the finite sampling time be realized, using events?

Is there another possibility to run external C-code functions using ccall and add the call at a certain rate to a symbolic system description? Ideally connecting it using inputs and outputs of the MTK system?

I would be grateful for general advice on best practices here.

Thanks in advance!

Edit: Just saw that FMI.jl has been updated 2 weeks ago.

2

Just register the function. See @register_symbolic

3

this is a discrete-time system and it requires the in-development support for synchronous programming

which is not quite available yet. You can still perform state estimation for MTK models in other ways, for example

4

Thanks, this seems to work!

5

That’s an interesting talk! Is there a timeline when this feature is to be published? How does this relate to tutorials → discrete_system (sorry I cannot add a link here)? Until the feature in the presentation is released, can I use events instead, specifically make ccalls in an event callback?

6

This is only for systems that are only discrete time, no continuous time dynamics.

Yes, it’s slightly cumbersome but not too bad if you have a single discrete-time component only

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