init

FOTF Toolbox/@foss/feedback.m

@@ -0,0 +1,24 @@
+function G=feedback(G1,G2)
+% feedback - find the overall model of two FOSS objects in feedback connection
+%
+%    G=feedback(G1,G2)
+%
+%   G1, G2 - the FOSS objects in the forward and backward paths
+%   G - the overall model of the closed-loop system
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 28 March, 2017 
+% Last modified 18 May, 2022 
+   G1=foss(G1); G2=foss(G2); 
+   if length(G1.alpha)>1 || length(G2.alpha)>1, a=0.0001;
+   else, a=common_order(G1.alpha,G2.alpha); end
+   if a==0
+      G=foss([],[],[],G1.d*inv(eye(size(G1.d))+G2.d*G1.d),0);
+   elseif a<0.001
+      G1=fotf(G1); G2=fotf(G2); G=foss(feedback(G1,G2));
+   else
+      G1=coss_aug(G1,round(G1.alpha/a));
+      G2=coss_aug(G2,round(G2.alpha/a));
+      G=foss(feedback(ss_extract(G1),ss_extract(G2))); G.alpha=a;
+   end
+end