National Instruments 370757C-01 用户手册

•

For  all 

ω ≥ 0,

•

Condition 1 is a standard condition to ensure the existence of a stabilizing 
controller. Condition 2 ensures that the control signal u is contained in the 
normalized error vector e (refer to Figure 4-3). Conversely, condition 3 
ensures that some exogenous input (disturbance or noise) affects the 
measured signals (refer to Figure 4-3). Conditions 4 and 5 ensure certain 
minimal realizations of subblocks of the extended plant ([GD88]).

[SysC,Syszw] = hinfcontr(SysAug,gamma,nw,nz,{method})

The 

hinfcontr( )

 function designs an H

∞

 controller for an augmented 

plant. The augmented plant should satisfy the five restrictions in the 

 section. The 

hinfcontr( )

 function 

tests for these restrictions and returns an error if they are violated. 

Assuming the restrictions are not violated, a controller satisfying 

 will exist if certain low-level conditions also hold. These 

involve conditions for the solution of the underlying Riccati equations 
and conditions for some other constraints. The details can be found in 
[GD88,DGKF89] and are beyond the scope of this manual. If the low-level 
conditions are violated, an error statement is displayed:

hinfcontr –>No stabilizing controller meets the spec!

Adjust gamma and try again!

When this occurs it means that the original 

gamma

 is too small and a 

larger

gamma

 (for example, a looser spec) is required to eliminate the 

error condition. If 

gamma

 is too small, or any other necessary condition 

is not met, the 

hinfcontr( )

 function returns a zero controller and the 

closed-loop system is equal to the open-loop system: 

SysC = system( [], [], [], 0 ),

Syszw = system(A, B1, C1, D11)

ωI

–

2

1

12

+

=

ωI

–

1

2

21

+

=

ew ∞

γ

≤