function [Kp,Ti,Td,key,lb]=pid_ho_tune(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
                switch id
                    case 1
                        Wp=(2*3.1416/4+0.5*3.1416*2)/(L*3);
                        Kp=Wp*T/(2*K);Ti=1/(2*Wp-4*(Wp)^2*L/3.1416+1/T);
                        key=1;
                    case 2
                        Wp=(3*3.1416/3+0.5*3.1416*6)/(L*8);
                        Kp=Wp*T/(3*K);Ti=1/(2*Wp-4*(Wp)^2*L/3.1416+1/T);
                        key=1;
                    case 3
                        Wp=(4*3.1416/4+0.5*3.1416*12)/(L*15);
                        Kp=Wp*T/(4*K);Ti=1/(2*Wp-4*(Wp)^2*L/3.1416+1/T);
                        key=1;
                end
        end
    case 2
        switch key2
            case 4       
                switch id
                    case 1
                        Am=3;fem=3.1416/4;
                        Kp=1.8578*(fem)^0.0821*(L/T)^(-0.9471)/((Am)^0.9087*K);
                        Ti=0.0211*T*(1+0.3289*Am+6.4572*fem+25.1914*L/T)/(1+0.0625*Am-0.8079*fem+0.347*L/T);
                        Td=0.4899*T*(fem)^0.1457*(L/T)^1.0264/(Am)^0.0845;
                        key=1;
                    case 2
                        Am=3;fem=3.1416/4;
                        Kp=1.0722*(fem)^(-0.116)*(L/T)^(-0.908)/((Am)^0.8432*K);
                        Ti=1.2497*T*(fem)^1.0082*(L/T)^0.3678/(Am)^0.2099;
                        Td=0.4763*T*(fem)^(-0.328)*(L/T)^1.0317/(Am)^0.0961;
                        key=1;
                end
        end
end