Working with Ill conditioned systems

2 次查看（过去 30 天）

Shelia kk 2011-4-27

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/6282-working-with-ill-conditioned-systems

 Hi, I have linear system (A(n x n),B(nxm),C(pxn) pairs, (where n = 9, m =1, p = 4). When I check the controllability or obsevability of the systems, matlab gives me the wrong answers that is

rank(obsv(A,C)) = 1. I tried with selecting C = eye(9) which means that i can measure all the variables. Then I must get rank(obsv(A,C)) = 9. But I still get rank(obsv(A,C)) = 1. When I check the singular value decomposition of A matrix and divide the max eigenvalue to minimum one, I get 2.6x10^21 , which is very big and causes all the errors in my simulation. I have to work with this system and find some transformation matrices to design my controller but since the system is ill-conditioned, i always get wrong results. What should I do? Please help. Thanks