pta_mdp.m

% PTA_MDP
%
%   Analytical method for controller tuning by Multiple dominant pole method
%
%   [zr,ti,td] = pta_mdp(typ_m,typ_c,n,K,T)
%
%   where
%
%   typ_c - is variable for choice of the controller type
%      typ_c == 2 for PI Controller
%      typ_c == 3 for PID Controller
%
%   n - is order of the proces model
%   K - is gain of proces model
%   T - is time constant of proces model
%
%   typ_m == 2:
%
%             K
%   G(s) = -------*exp(-Ds)
%           T*s+1
%
%
%   typ_m == 3:
%
%               K
%   G(s) = -------------
%          s*(T*s+1)^(n)
%
%   2011.03.17.
%


function [zr,ti,td] = pta_omm(typ_m,typ_c,n,K,T)

if(typ_m == 2)

% PI Controller
%
if(typ_c == 2)

    zr = (1/K)*(((n-1)/(n+1))^(n-1));
    ti = T*(((n+1)^2)/(4*n));
    td = 0;

% PID Controller
%
elseif(typ_c == 3)

     zr=((5*n-4)/(K*(n+1)))*(((n-2)/(n+1))^(n-2));
     ti=(5*T*(5*n-4)*(n+1)^2)/(27*n*(n-1));
     td=T*(n+1)*n/(2*(5*n-4));

else
    
    zr = Inf;
    ti = Inf;
    td = Inf;
    
end

elseif(typ_m == 3)

% P Controller
%
if(typ_c == 1)

    zr = 1/(K*T*(n+1)) * ((n)/(n+1))^(n);
    ti = 1e10;
    td = 0;

% PD Controller
%
elseif(typ_c == 4)
    
    zr = (4*n)/(K*T*(n+1)^2)*((n-1)/(n+1))^(n-1);
    ti = 1e10;
    td = (T*(n+1)^2)/(4*n);
    
else
    
    zr = Inf;
    ti = Inf;
    td = Inf;
    
end
% ---------- %
%
% No required model form found
%
else
    
    zr = Inf;
    ti = Inf;
    td = Inf;
    
end