facing difficulties in desining h infinity controller for a 5th order system

achow pal — Sun, 08 Nov 2009 12:47:01 -0500

i have written a matlab code for desiging the h infinty controller for 5th order plant
i am gettng the errors.i am pasting my code here
clc
clear
ws=104;
wsl=0.1*ws;
p=3.14;
Ts=-1;
kl=1000;
wl=50;
wh=100;
kh=10^-4;
%state space equations of plant model
b1=[1 0 0 0 ;0 1 0 0 ;-1600 0 0 0 ;0 -1600 0 0 ];
b2=[0 0;0 0;1647 0;0 1647];
c2=[1 0 0 0;0 1 0 0;0 0 1 0;0 0 0 1];
c1=[0 0 -1 0;0 0 0 -1];
d11=[0 0 1 0;0 0 0 1];
d12=[0 0;0 0];
d21=[0 0 0 0;0 0 0 0;0 0 0 0;0 0 0 0];
d22=[0 0;0 0;0 0;0 0];
a=[1.336 104.67 8.951e-3 0;-104.67 -1.336 0 8.95e-3;2140 (-167.7e3+(wsl)*1.6e3) 0 wsl;167.7e3 -wsl*1.6e3 2.14e3-wsl -24.38]
ss_g=mksys(a,b1,b2,c1,c2,d11,d12,d21,d22,Ts,'tss');
% weights
nw1=[0 kl];
dw1=[1 wl ];
w1=tf(nw1,dw1);
x=[w1 0;0 w1];
sys1 = ss(x);
[aa,bb,cc,dd] = ssdata(sys1)
wt1=mksys(aa,bb,cc,dd);
nw2=[kh 0 ];
dw2=[1 wh ];
w2=tf(nw2,dw2);
y=[w2 0;0 w2];
sys2 = ss(y);
[aa1,bb1,cc1,dd1] = ssdata(sys2)
wt2=mksys(aa1,bb1,cc1,dd1);
w3= mksys([],[],[],[]);
tssp=augss(ss_g,wt1,wt2,w3,[]);
[ssf,sscl,l]=hinf(tssp);
-----------------------------------------------------------------------------
i am getting the following error

Error in ==> mkargs5x at 60
emsg='';

??? Output argument "nag1" (and maybe others) not assigned during call to "C:\Program
Files\MATLAB\R2008b\toolbox\robust\rctobsolete\robust\mkargs5x.m>mkargs5x".

Error in ==> augss at 31
[emsg,nag1,xsflag,Ts,ag,bg,cg,dg,aw1,bw1,cw1,dw1,aw2,bw2,cw2,dw2,aw3,bw3,cw3,dw3,w3poly]=mkargs5x('ss',varargin);
error(emsg);

Error in ==> important at 38
tssp=augss(ss_g,wt1,wt2,w3,[]);

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facing difficulties in desining h infinity controller for a 5th order system