s = tf('s')
C =@(Kp,Ti) (Kp + Kp/(Ti*s))
G = tf([6],[48 44 12 1])

Kp = [0.3 0.5 0.7];
Ti = [20 20 20];

figure
ax = axes;
hold(ax,'on');


for i = 1:length(Kp)
H = feedback(C(Kp(i),Ti(i))*G,1,-1)
step(H)
end

gLegend = arrayfun(@(Kp,Ti) sprintf('Kp = %i, Ti = %i',Kp,Ti),Kp,Ti,'UniformOutput',false)
legend(ax,gLegend)