How can I fix this error?
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Siddhanth Sunil Shah
on 7 Jan 2022
Edited: Siddhanth Sunil Shah
on 10 Jan 2022
A = [-3 5 -7 0; 0.5 -1.5 0.5 -7.5;-5 0 -3 0; -0.5 -5 0 .7];
B = [1 0 0; 0 -1 0; -2 0 0; 0 1 2];
C = [1 0 0 0; 0 -1 0 0];
D = [-1 0 0; 2 0 0];
SS = ss(A, B, C, D)
G = tf(SS)
S = smithForm(G)
I get the following error. I want to convert the four matrices A,B,C,D into the transfer function G and bring the system in the Smith Form. How can I convert the transfer function matrix into single, double or sym matrix so that I can appy SmithForm()?
Error using smithForm (line 80)
Invalid data type. First argument must be double, single, or sym matrix.
Error in Q5 (line 55)
S = smithForm(G)
2 Comments
Accepted Answer
Star Strider
on 7 Jan 2022
Ad = [-3 5 -7 0; 0.5 -1.5 0.5 -7.5;-5 0 -3 0; -0.5 -5 0 .7];
As = sym(Ad*10) % Multiply By '10' To Produce Integers & Create As Symbolic
S = smithForm(As)
Multiplying by 10 is necesary here, because as the documentation states ‘A’ must be a ‘square invertible symbolic matrix’ and ‘The elements of A must be integers or polynomials’.
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6 Comments
Star Strider
on 7 Jan 2022
Edited: Star Strider
on 7 Jan 2022
Interesting. I could not find that term on an Interweb search earlier today.
I will read the paper and see what I can find in that regard.
EDIT — (7 Jan 2022 at 17:34)
The paper requires the context of already being familiar with many of the references, and I am not. (Some of the variables such as
arise de novo with no explanation or definition, so it is likely that understanding this paper requires being familiar with the references.)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/856450/image.png)
There are no Control System Toolbox functions that I am aware of that would specifically design those compensators, so it would be necessary to design the compensators yourself. The Control System Toolbox functions can likely do that, and it would then be possible to use appropriate existing functions to connect them to the system.
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