Patent Document ID: 20070250186
Application ID: 11572778
Patent Flag: 0

Claim One:
1 : A robust digital controller, comprising: a control compensating means for realizing an integral type control system that is obtained by equivalently converting a system and is connected with a control target satisfying the following state equation 1 when an input h, a controlled variable y, a first equivalent disturbance q v , a second equivalent disturbance q v and a time-lag ξ 1 are respectively given: 
 x d ( k+ 1)= A d x d ( k )+ B d h ( k ) 
 y ( k )= C d x d ( k )+ q y ( k ) 
 where x d =[xξ] T Equation 1 wherein said system is formed by approximating a transfer function W ry (z) between a target value r and said controlled variable y when a state feedback rule and a feedforward rule are applied to said control target to determine a quadratic approximate model transfer function W m (z) shown in the following equation 2: W ry = ⁢ ( 1 + H 1 ) ⁢ ( 1 + H 2 ) ⁢ ( 1 + H 3 ) ⁢ ( z - n ⁢ ⁢ 1 ) ⁢ ( z - n ⁢ ⁢ 2 ) ⁢ ( z + H 4 ) ( 1 - n ⁢ ⁢ 1 ) ⁢ ( 1 - n ⁢ ⁢ 2 ) ⁢ ( z + H 1 ) ⁢ ( z + H 2 ) ⁢ ( z + H 3 ) ⁢ ( z + H 4 ) ≈ ⁢ W m = ( 1 + H 1 ) ⁢ ( 1 + H 2 ) ⁢ ( z - n 0 ) ( z + H 1 ) ⁢ ( z + H 2 ) ⁢ ( 1 - n 0 ) Equation ⁢ ⁢ 2 (where z=exp(jωt); n 0 , n 1 , n 2 are zeros; and H 1 , H 2 , H 3 , H 4 are poles.) and then said system is configured by combing the model transfer function W m (z), an inverse function W m (z) −1 of said model transfer function W m (z) and a dynamic compensator K(z) with characteristics shown in the equation 3 for realizing the inverse function W m (z) −1 : k ⁡ ( z ) = k z z - 1 + k z Equation ⁢ ⁢ 3