Yalmip LMI solving H2 optimal control problem run into numerical problem

30 views (last 30 days)
Hi, everybody ,l am trying to use Yalmip toolbox to solve H2 optimal control problem,
l use the following LMI, While there is something wrong with my code, l can't get the expected result,
clear;
clc;
% system parameters
A = [-3 -2 1;
1 2 1;
1 -1 -1];
B1 = [1 0.2 0]';
B2 = [0.4 1 0.6]';
C1 = [1.2 0.5 0.3];
D12 = 1;
% declare the variable
P = sdpvar(3);
Z = sdpvar(1);
F = sdpvar(1,3);
mu = sdpvar(1);
% describe the LMI
mat1 = [A*P+P*A'+B2*F+F'*B2' P*C1'+F'*D12';
(P*C1'+F'*D12')' -eye(1)];
mat2 = [Z B1';
B1 P];
% declare the constraints
F = [mat1=<0; mat2>=0; P>=0; Z>=0 ;trace(Z)<=mu];
optimize(F, mu);
% result
Kd = value(F)*inv(value(P))
H2_norm = sqrt(value(mu))
I get the following result ,
SeDuMi 1.3 by AdvOL, 2005-2008 and Jos F. Sturm, 1998-2003.
Alg = 2: xz-corrector, theta = 0.250, beta = 0.500
eqs m = 11, order n = 14, dim = 44, blocks = 4
nnz(A) = 61 + 0, nnz(ADA) = 97, nnz(L) = 54
it : b*y gap delta rate t/tP* t/tD* feas cg cg prec
0 : 2.90E+00 0.000
1 : -6.66E-01 6.49E-01 0.000 0.2239 0.9000 0.9000 1.72 1 1 1.9E+00
2 : -7.69E-01 1.94E-01 0.000 0.2995 0.9000 0.9000 1.17 1 1 5.3E-01
3 : -9.76E-01 6.63E-02 0.000 0.3410 0.9000 0.9000 0.50 1 1 2.2E-01
4 : -1.18E+00 2.25E-02 0.000 0.3396 0.9000 0.9000 0.25 1 1 9.0E-02
5 : -1.44E+00 9.77E-03 0.000 0.4343 0.9000 0.9000 0.10 1 1 6.0E-02
6 : -1.75E+00 3.75E-03 0.000 0.3836 0.9000 0.9000 0.03 1 1 3.7E-02
7 : -2.16E+00 1.33E-03 0.000 0.3553 0.9000 0.9000 0.22 1 1 1.9E-02
8 : -2.46E+00 5.28E-04 0.000 0.3964 0.9000 0.9000 0.23 1 1 1.1E-02
9 : -2.79E+00 1.44E-04 0.000 0.2725 0.9000 0.9000 0.58 1 1 3.6E-03
10 : -2.93E+00 3.91E-05 0.000 0.2716 0.9000 0.9000 0.68 1 1 1.2E-03
11 : -2.99E+00 3.03E-06 0.000 0.0775 0.9900 0.9900 0.90 1 2 9.5E-05
12 : -2.99E+00 1.98E-07 0.000 0.0653 0.9900 0.9900 0.97 1 2 6.3E-06
13 : -2.99E+00 3.82E-08 0.000 0.1934 0.9000 0.9000 0.93 3 3 1.3E-06
14 : -2.99E+00 1.16E-08 0.000 0.3044 0.9000 0.9000 0.76 7 4 4.6E-07
15 : -2.99E+00 4.26E-09 0.000 0.3662 0.9000 0.9000 0.60 16 14 2.1E-07
Run into numerical problems.
iter seconds digits c*x b*y
15 0.1 5.9 -2.9940592991e+00 -2.9940558596e+00
|Ax-b| = 2.8e-07, [Ay-c]_+ = 6.4E-08, |x|= 2.2e+02, |y|= 1.7e+02
Detailed timing (sec)
Pre IPM Post
8.500E-02 1.940E-01 7.800E-02
Max-norms: ||b||=1, ||c|| = 2,
Cholesky |add|=0, |skip| = 0, ||L.L|| = 167.62.
the error message:
错误使用 lmi/value (line 12)
Double not applicable on list of constraints
出错 H2_state_feedback_control_LMI_method (line 274)
Kd = value(F)*inv(value(P))
any suggestions will be appreciated!
Thanks in advance!
  4 Comments
yuan
yuan on 9 Jul 2020
l use the variable F two times, but it is not the same things , so l can't get the result .
Great thanks to Professor Johan. By the way, the constrains can't be strict inequalities or you will get sad Kittens.
making the following changes,it will works!
% declare the constraints
Fd = [mat1=<0; mat2>=0; P>=0; Z>=0 ;trace(Z)<=mu];
optimize(Fd, mu);
% result
Kd = value(F)*inv(value(P))
H2_norm = sqrt(value(mu))

Sign in to comment.

Answers (0)

Products


Release

R2018b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!