How to find derivative of one output signal with respect to other using simulink???

 I built up a full vehicle simulink model in which i need to find out differenciation of one output signal with respect to other output signal and value of this is again sent back as input to my model.So can any body tell me How to find derivative of one output signal with respect to other using simulink???

[Yao Li]

I do recommand u to revise your algorithm because derivative leads to noise. If there are close-loops, try to exchange the inner loop with the outer loop which will change derivative to integration. I built up the full vehicle model myself. If you do have to calculate the drivative, try change dy/dx to (dy/dt)/(dx/dt), but not a good solution.

[Yao Li]

Actually, derivative will not lead to noise but influenced greatly by noise.

[Amar]

whether logic of chain rule of derivatives is really applicable in simulink....if i use dy/dx = (dy/dt)/(dx/dt) it outputs a value as NaN because at t=0 it gets the value = 0/0 how to overcome this situation.

[Yao Li]

Many ways. triggered subsystem or if..else or any other ways to give a nonzero initial value of dx/dt or delay the calculation of dx/dt

Answer 1

[Rock]

Is any block on simulink where chain rule differentiation is applicable?

Answer 2

[Iain]

You could just calculate (difference in signal 1 over "a timestep")/(difference in signal 2 over "the same timestep").