MATLAB Answers

0

Any suggestions of Q and R to my LQR representation to get reasonable step response?

Asked by HAITHAM AL SATAI on 2 Jun 2019
Latest activity Edited by Raj
on 3 Jun 2019
This is below my code :
% Define the matrix A, B, C, D
A=[0,1,0,0;0,-42.44,212.24,0;0,0,0,1;0,0,0,-42.44];
B=[0,0;106.12,-5;0,0;78.6,-42.44];
C=[1,0,0,0;0,1,0,0;0,0,1,0;0,0,0,1];
D=[0];
%Detect the controllability of the Given system
Qc= ctrb(A,B);
rank_of_Qc = rank(Qc)
x = 1;
Q = diag([x 0 0 0]);
R=[0.9,0;0,0.9];
K=lqr(A,B,Q,R)
%Find step response of LQR controller
LQRcontroller_sys=ss(A-B*K,B,C,D)
t=0:0.1:10;
step(LQRcontroller_sys,t)
grid on;
This is my results
My system

  1 Comment

What do you mean by "reasonable step response"? You can tune the LQR weight matrices (Q & R) to get whatever output response you need. Depends on what you want to achieve.

Sign in to comment.

0 Answers