Is it possible to get correct result in simulink if derivative block is used to obtain the derivative of a signal? If not how to obtain derivative of signals in matlab/simulink?

I am working on control system and i am using simulink for my my design and analysis, so in my design I need to perform derivative of signals. I used derivative block of simulink for this purpose and it gives correct result sometimes and error sometimes. so I would like know whether it is correct or not?

Answer 1

[Sebastian Castro]

The Derivative block only approximates a derivative and can therefore be very unstable when the derivative of a signal is high.

The usual workaround, which is what the continuous-time PID Controller block in Simulink can do, is to implement a filtered derivative. See section 3c of the following Answer for more details:

http://www.mathworks.com/matlabcentral/answers/95614-what-are-the-implications-of-using-the-derivative-block-in-simulink

- Sebastian

[arobindra saikia]

Thank you sir for your reply.