How can I use k (controller) in "hinfsyn"(H infinity controller)

Hi, By using "hinfsyn" to design an H infinity controller, the output k (controller) has 4 parts a, b, c, d. I do not know how I can exactly use this parts to find the transfer function of the controller. can anybody tell me which command I should use to find the k(s). Also I have some difficulties to use the "hinfsyn". P (plant) used in the "hinfsyn" has to be made by "augw"? If I dont want to use weights (W1, W2, W3) is there any other way to find P, or even other command to design H infinity controller?

Answer 1

[Özgür]

Hello,

if you calculated succesfully your H-inf controller with state-space representation (as you mentioned you will get 4 part called a,b,c,d) you can convert it to laplace form with below code.

[Ak Bk Ck Dk]=unpck(K_hin);

K_ss=ss(Ak,Bk,Ck,Dk);

tf(K_ss);

About the weight, this is very critical question because those weights are key to design of robust control. So without weights we can not say the final controller will be robust. I prefer to you get some more information about the robust theory for example on Skogestad book.