function gp = model(caseNumber)

s=tf('s');

switch caseNumber
    case 1
        gp=tf(1);
    case 2
        gp = 1/(s+1); 
    case 3
        gp = 1/(8*s+1);
    case 4
        gp = 1/(s);
end

gp.outputd = 1;
