Derivative Block is Linearized to Zero

I'm trying to linearize a model where the output is dependent on the derivative of a signal. The derivative block has the following diagnostic message in the linearization advisor:

1. Derivative block is linearized to zero when Linearization Time is set to Inf. Please consider using a finite number for the Linearization Time parameter.

My system is time-continuous, so I have the 'SampleTime' option set to 0, but this doesn't seem to be what the diagnostic is referring to. I've tried both model trimming, and linearizing about a time where the model has reached steady state, but this message appears in each case. I've also tried using the 'Switched derivative for linearization' block, but this doesn't seem to have fixed it either.

I can't find any other documentation referring to this linearization time parameter. How can I change it and what is its meaning?

Answer 1

[Kiran Felix Robert]

Hi Nicholas,

The Linearization Time parameter mentioned in the Linearization advisor is the parameter ‘c’ which you set in the derivative block (It is currently set to inf) . For linearization of a derivative block a finite positive value of the parameter ‘c’ is advised. To know more about the parameter ‘c’ and a suggested value for it you can refer to the derivative block documentation.

Kiran Felix Robert