Unrecognized function or variable

Question

Aysel Alimirzayeva 2022-10-13

评论： Aysel Alimirzayeva 2022-10-14

Hello. I wrote an example of the diskmarginplot function in Matlab 2019Rb version, but it gives an error. Please help me.

DGM 2022-10-13

Where is diskmarginplot.m? Did you add it to the path or place it in a directory that's on the path?

Answer 1

Sam Chak 2022-10-14

It requires Robust Control Toolbox, the function is introduced in R2020a. Since yours is R2019b, then I think ...

s = tf('s');

G = 0.38*(s^2 + 0.1*s + 0.55)/(s*(s + 1)*(s^2 + 0.06*s + 0.5))

G = 0.38 s^2 + 0.038 s + 0.209 --------------------------------- s^4 + 1.06 s^3 + 0.56 s^2 + 0.5 s Continuous-time transfer function.

diskmarginplot(G)

@Sam Chak Thank you very much.