Alternative to the Differential block

hello,everyone!

I need to find the derivative of the system output in the simulink model. I used the derivative block(please see the attached figure) but the display is wrong. I asked someone to tell me why and he told me that the derivative block is indeed prone to problems. So it is best to replace it when necessary. Therefore, I would like to ask what kind of approximate differential method can replace this derivative block? Thanks.

[Paul]

Hard to say without more information, but it may be possible to slightly refactor the model to extract the derivative directly. Would need to know how the output is computed.

Answer 1

[Sam Chak]

Hi @Joe Jones

You can try the Robust Exact Differentiator Block:

http://www.reichhartinger.at/

[Joe Jones]

Dear

Thank you for your advice!

I download the ‘differentiator_v3.zip’ and replace the previous block with the robust exact differentiator block. However, the model does't run. The main error can be seen in the attached figure. Besides, there are many minor errors like 'Input ports (4, 5, 6) of 'cgadrc_test/cg1/MATLAB Function' are involved in the loop'. I think these minor errors may be caused by main error. As long as the main error is solved, the minor errors should be solved. If possible, please help me. Thank you!@Sam Chak