m = 1; k = 10; c = -0.1; A = [-c/m, -k/m; 1, 0]; % unstable plant B = [1/m; 0]; %C = [0, 1]; % original setting but not used Uc = ctrb(A,B); det(Uc) % ***1st disp.*** should be nonzero, which means (A,B):controllable C = eye(2); D = zeros(2,1); % state feedback F = [0, 0]; % without control x0 = [1; 1]; % initial state Q = eye(2); R = 1; P = are(A, B/R*B', Q); eig(P) % ***2nd disp.*** should be positive F = R\B'*P; Jmin = x0'*P*x0 % ***3rd disp*** to be compared with Simulink mod0927_1;