z = 2; t1 = 1; t2 = 2; ts = 1;
G = tf(z, conv([t1 1],[t2 1]));
gz = c2d(G, ts);
zinteg = tf([1 0],[1 -1], ts);

% convert to Polynomial toolbox format manually
[b,a]=tfdata(gz, 'v');
zii = [1; zi; zi^2];
b = b * [1; zi; zi^2];
a = a * [1; zi; zi^2];
a = a * (1-zi); % add integrator

%Design the DB controller
[x0,y0]=axbyc(a,b,1);
tt = -1;
x = x0 - b * tt;
y = y0 + a * tt;