National Instruments 370757C-01 用户手册

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4.

For this example, you will start with 

gamma=1

 as the initial guess and 

enter: 

[K,Hew] = hinfcontr(P,1,2,2);

No error messages are reported. This means that a stabilizing 
controller has been found such that Equation 4-1 holds. That is, 

.

The actual H

∞ norm is found from:

normHew=linfnorm(Hew)

gamma = 1 Æ  normHew = 0.212

 gamma:

[K,Hew] = hinfcontr(P,.2,2,2);

normHew=linfnorm(Hew)

[K,Hew] = hinfcontr(P,.15,2,2);

normHew=linfnorm(Hew)

[K,Hew] = hinfcontr(P,.13,2,2);

normHew=linfnorm(Hew)

[K,Hew] = hinfcontr(P,.12,2,2);

normHew=linfnorm(Hew)

The iterations establish that 

γ

 lies between 0.12 and 0.13. Figure 4-5 

shows the output of the 

perfplots

 function on the closed-loop 

system H

 for 

γ = 0.13. 

[K,Hew] = hinfcontr(P,.13,2,2);

normHew = linfnorm(Hew, {tol=1e-3})

svHew = perfplots(Hew,1,1,{Fmin=0.01,Fmax=100});

ew ∞

1

≤