How to avoid the numerical instability when solving the step response of a dynamic system?

Questions
,
1

Dear there,

I am plotting the step response of a dynamic system with the transfer function matrix “tfm1” as below:

Tf.png
Tf.png473×145 9 KB

.

I use:

stepr = OutputResponse[tfm1, {UnitStep[t],0}, t]; 

Plot[Abs[stepr], {t, -2, 8}]

Then I get the plotted figure as below:

plot.png
plot.png763×472 24.4 KB

.

Obviously around t = 6.3 seconds, the results become unstable and cannot come to the steady state. Is there any method to increase the numerical stability of the step response calculation? Thank you!

Kind regards,

Jin

2
Open in Wolfram Cloud ↗
3

Hi Mariusz,

Thank you very much for offering your help. Much appreciated!

Kind regards,

Jin