SS2TF Error

26 views (last 30 days)
Anthony Sirico
Anthony Sirico on 31 Jan 2021
Answered: Paul on 1 Feb 2021
sysm s R1 R2 C1 C2
A = [-(R1+R2)/(C1*R1*R2) 1/(C1*R2); 1/(C2*R2) -1/(C2*R2)];
B = [1/(C1*R1); 0];
C = [0 1];
D = 0;
After executing, i get:
Error using ss2tf (line 26)
The following error occurred converting from sym to double:
Unable to convert expression containing symbolic variables into double array. Apply 'subs' function first to substitute values for
Error in sstf (line 8)
I am not familiar with subs, can someone explain?

Answers (2)

madhan ravi
madhan ravi on 31 Jan 2021
State space representation should be with numerical values and it cnnot contain symbolic values.

Paul on 1 Feb 2021
If you want the numerical answer, then don't even bother with the symbolic stuff. Just assign values to the variables R1, R2, C1, and C2 and go from there.
If you really want the symbolic expression:
and then proceed from there.


Find more on Symbolic Math Toolbox in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!