FPID_RECS Approximate BIBO stability rectangle for FOPID control system
Usage: [P1_LIMS,P2_LIMS]=FPID_RECS[P1,P2,DP,INIT,CL_POLY_FUN,OP)
where P1_LIMS, P2_LIMS - stability limits of first and second coord.
P1, P2 - string with first and second coordinates to sweep,
may be one of 'Kp', 'Ki', 'Kd', 'lambda', or 'mu',
NB! All parameter names are case-sensitive!
DP - sweeping step, either scalar or
vector of form [DP1; DP2],
INIT - structure with initial coordinate of the form
INIT.Kp = ..., INIT.Ki = ..., etc.,
NB! Parameter names are defined exactly as above.
CL_POLY_FUN - a function handle which must accept five
arguments in the form (Kp,Ki,Kd,lambda,mu) and
return a fotf object having the closed-loop pole
polynomial corresponding to the control system
with the FPID controller
OP - Structure with additional options (optional):
OP.maxPoints = N, where N is the points to check
from the center point in every
direction (i.e. from initial
coordinates), default: 100,
OP.displayPlot = 0 or 1 - draw the approximate
stability region.
OP.progress = 0 or 1 - display progress of
computation
OP.drawUnstable= 0 or 1 - draw unstable points on
the stability plane
(this only works if
displayPlot is
activated.)
The algorithm uses Matignon's stability theorem to determine
BIBO stability of closed-loop commensurate-order systems with
parallel form FOPID controllers in the loop.
If systems are not commensurate-order, the stability test
my produce unreliable results.
See also: fotf/isstable, fpid_recs_ini