function [Kp,Ti,Td,key,lb]=pid_ta_tune(lambda,G,key1,key2,vars)  
key=0; Kp=[]; Ti=[]; Td=[]; lb=[];
K=vars(1); L=vars(2); T=vars(3); id=vars(4);

switch key1
    case 1
        switch key2
            case 4
                [Gm,Pm,Wcg,Wcp]=margin(G);
                Ku=1/abs(Gm);
                Tu=2*3.1416/Wcg;
                if L/T<0.5
                    b=0.8;
                else
                    b=0.5;
                end
                 [m,p,w]=bode(G);
                 i=find(p<-lambda);
                 i(1);
                 w=w(i(1));
                 Ti=1/(b*w*tan(-atan(b)*T*w-b*L*w-lambda));
                 Kp=b*Ti*w*(1+(b*T*w)^2)^0.5/(Gm*(1+(b*Ti*w)^2)^0.5);
                 
                 key=1;
       end
    case 2
        switch key2
            case 6
                [Gm,Pm,Wcg,Wcp]=margin(G);
                Ku=1/abs(Gm);
                Tu=2*3.1416/Wcg;
                switch id
                    case 1
                        Kp=Ku*1.414/4;
                        Td=Tu*(1+(4/lambda+1)^0.5)*0.25/3.1416;
                        Ti=lambda*Td;
                        key=1;
                    case 2
                        Gf=tf(K,[T,1],'iodelay',L);
                        [m,p,w]=bode(Gf);
                        m=m(:); p=p(:);
                        [mm,i]=sort(abs(p+lambda));
                        w=w(i(1));
                        [Gm1,Pm1,Wcg1,Wcp1]=margin(Gf);
                        Kf=1/abs(Gm1);
                        r=0.1+0.9*Ku/Kf;
                        Kp=Ku/2;
                        Ti=r*Kf*(Wcg^2-w^2)/(w*Wcg^2*(Ku^2-r^2*Kf^2)^0.5);
                        Td=1/(w^2*Ti);
                        key=1;
                end
       end
end