How do we choose matrices in state feedback control?

I have a system like the one showed in the picture. In order to use the commande lqr, we need to specify the matrices A, B, C,D but i don't know which of bu and bv should i take? Or do we assume that Cr=0?

Answer 1

[Paul]

Hi Luc,

For lqr, the B matrix multiplies the control input. As I don't know what the variables mean in your problem, I can only guess that the control input is u_cm and that phi_r is an exogenous input, in which case one would use b_u.

There is no Cr in the attached equations, so not sure what the qeustion is about that.

Also, the attached equations are incorrect; the terms transpose(C_s) should just be C_s.

[Luc RABE]

Hi, thank you for your reply, so the correct command would be K=lqr(As, bu, Q, R). About the latest question i put phi_r instead of Cr.