Loop recovery via ℋ︁ ∞ ‐modified complementary sensitivity recovery for non‐minimum phase plants

In order to recovery robust stability of a desirable state feedback system by output feedback, the desirable complementary function is approximated by a modified complementary function of the output feedback system by solving an ℋ ∞ norm‐minimization problem. The modified complementary function is obtained by getting rid of non‐minimum phase factors from the complementary function. Numerical examples show the superiority of this method to LQG/LTR method and other methods.