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H_inf(1) Scilab Function H_inf(1)
NAME
h_inf - H-infinity (central) controller
CALLING SEQUENCE
[Sk,ro]=h_inf(P,r,romin,romax,nmax)
[Sk,rk,ro]=h_inf(P,r,romin,romax,nmax)
PARAMETERS
P : syslin list : continuous-time linear system (``augmented''
plant given in state-space form or in transfer form)
r : size of the P22 plant i.e. 2-vector [#outputs,#inputs]
romin,romax : a priori bounds on ro with ro=1/gama^2; (romin=0 usually)
nmax : integer, maximum number of iterations in the gama-
iteration.
DESCRIPTION
h_inf computes H-infinity optimal controller for the continuous-time plant
P.
The partition of P into four sub-plants is given through the 2-vector r
which is the size of the 22 part of P.
P is given in state-space e.g. P=syslin('c',A,B,C,D) with A,B,C,D = con-
stant matrices or P=syslin('c',H) with H a transfer matrix.
[Sk,ro]=H_inf(P,r,romin,romax,nmax) returns ro in [romin,romax] and the
central controller Sk in the same representation as P.
(All calculations are made in state-space, i.e conversion to state-space is
done by the function, if necessary).
Invoked with three LHS parameters, [Sk,rk,ro]=H_inf(P,r,romin,romax,nmax)
returns ro and the Parameterization of all stabilizing controllers:
a stabilizing controller K is obtained by K=lft(Sk,r,PHI) where PHI is a
linear system with dimensions r' and satisfy:
H_norm(PHI) < gamma. rk (=r) is the size of the Sk22 block and ro =
1/gama^2 after nmax iterations.
Algorithm is adapted from Safonov-Limebeer. Note that P is assumed to be a
continuous-time plant.
SEE ALSO
gamitg, ccontrg, leqr
AUTHOR
F.D. (1990)
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