home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
OS/2 Shareware BBS: 10 Tools
/
10-Tools.zip
/
octa21eb.zip
/
octave
/
SCRIPTS.ZIP
/
scripts.fat
/
control
/
h2norm.m
< prev
next >
Wrap
Text File
|
1999-04-29
|
2KB
|
59 lines
# Copyright (C) 1996,1998 A. Scottedward Hodel
#
# This file is part of Octave.
#
# Octave is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2, or (at your option) any
# later version.
#
# Octave is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
# for more details.
#
# You should have received a copy of the GNU General Public License
# along with Octave; see the file COPYING. If not, write to the Free
# Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
function h2gain = h2norm(sys)
# Usage: h2gain = h2norm(sys)
#
# Computes the H2 norm system data structure (continuous time only)
# sys = system data structure [see ss2sys()]
# returns h2gain = Inf if system is unstable
#
# Reference:
# Doyle, Glover, Khargonekar, Francis, "State Space Solutions to Standard
# H2 and Hinf Control Problems", IEEE TAC August 1989
#
# A. S. Hodel Aug 1995
# updated for system data structure by John Ingram November 1996
if((nargin != 1))
usage("h2gain = h2norm(sys)");
elseif(!is_struct(sys))
error("Sys must be in system data structure");
end
dflg = is_digit(sys);
if(!is_stabl(sys))
warning("h2norm: unstable input system; returning Inf");
h2gain = Inf;
else
# compute gain
[a,b,c,d] = sys2ss(sys);
if(dflg)
M = dlyap(a,b*b');
else
M = lyap (a,b*b');
endif
if( min(real(eig(M))) < 0)
error("h2norm: grammian not >= 0 (lightly damped modes?)")
endif
h2gain = sqrt(trace(d'*d + c*M*c'));
endif
endfunction