tfn3.m

内模控制器（IMC）工具箱。包括参数整定、PID控制器参数转换等

function [p]=tfn3(k,n,d,td)

[nr,nc]=size(n);
[dr,dc]=size(d);
T=td;
numstr='';
if nr==0
   numstr='';
else
      for i=1:nr
      str_n=['(',poly2str(n(i,:),'s'),')'];
      numstr=[numstr,'*',str_n];
   end
end
denstr=['(',poly2str(d(1,:),'s'),')'];
for i=2:dr;
   str_d=['(',poly2str(d(i,:),'s'),')'];
   denstr=[denstr,'*',str_d];
end
%Form the transfer function in time constant form----------------
%Time Constant From:
%gain*numerator
%--------------exp(-td*s)
%Denomenator
%

a=n(1,:);
b=d(1,:);
for i=2:nr
   a=conv(a,n(i,:));
end
 for i=2:dr
    b=conv(b,d(i,:));
 end
 
   a=k*a;
   p=tf([a],[b],'iodelay',T);