Discretizing a continuous state model for use in HIL

I have developed a model with continuous integrators. To discretize them, i had replaced them with discrete integrators,its working fine for Ts=1e-4, but i need to use Ts=1e-3; where its not getting simulated properly.

Anyone any suggestions,please post. Thanks

Answer 1

[Azzi Abdelmalek]

You didn't precise how you replaced the other blocks, and I don't think you are doing the right thing. You also did not give enough information about your model (linear or not for example). If your model is linear you can use the function c2d to discretize it.

[Shyam]

Its a non linear system with 5 equations. Except for continuous integral blocks (1/s), there are no other continous blocks...As mentioned, i replaced them with discrete time integrators, which are working fine for Ts=1e-4, but not for 1e-3.

[Azzi Abdelmalek]

To be sure that you are doing the right thing, don't replace any block, just put a ZOH block with desired sample time after each output of your model (if your model is mimo) and before each input. Another important thing is: how did you choose the sample time, you can't set any sample time you want, it depends on the dynamic of your model, maybe 1e+3 is too large

[Shyam]

1e-3 as required by HIL, which works only with discretized models...with zoh at the input and fedback signal and with Ts=1e-3...works fine..