A = [0 1 0 0; 1 0 0 0; 0 0 0 1; -0.5 0 0 0]; B = [0; 1; 0; -1]; C = [0 0 1 0]; D = 0; p = [-1; -1; -1+j; -1-j]; x0 = [0.175 0 0 0]; K = acker(A, B, p) A1 = A-B*K; sys = ss(A1,B,C,D); initial(sys, x0); step(sys); impulse(sys);