how to title the stepplot?

how to give title of the each stepplot of transfer function?

i did this and its giving error

clear all
%muhammad sulaman
%19-ee-65
s=tf('s')
wn=0.7;
k=1;
% z=input('enter the value of zeta::');
z=[0 0.1 0.2 0.5  0.7 0.8 0.9 1]
for ii=1:1:8
    l=z(ii)
    t=linspace(1 ,100,1)
num=k*(wn^2)
den= s^2+2*l*wn*s+wn^2
sys(ii)=num/den
end
stepplot(sys(1),sys(2),sys(3),sys(4),sys(5),sys(6),sys(7),sys(8),t)
legend(sys(1),sys(2),sys(3),sys(4),sys(5),sys(6),sys(7),sys(8),'zeta 0','zeta 00.1','zeta 0.2','zeta 0.5','zeta 0.7''zeta 0.8''zeta 0.9','zeta 1')

[Ravi Narasimhan]

I don't have the Toolbox to run your code but I think the legend command does not require the sys(1)...sys(8).

There's an example with legend in the stepplot documentation: https://www.mathworks.com/help/control/ref/lti.stepplot.html

and

legend is described in: https://www.mathworks.com/help/matlab/ref/legend.html

What happens if you try

legend('zeta 0','zeta 00.1','zeta 0.2','zeta 0.5','zeta 0.7''zeta 0.8''zeta 0.9','zeta 1')

Answer 1

[Walter Roberson]

ch = get(gca,'children');
h = flipud(ch(1:7));
legend(h, {'zeta 0','zeta 00.1','zeta 0.2','zeta 0.5','zeta 0.7''zeta 0.8''zeta 0.9','zeta 1'})

This assumes that zeta 0 is intended to match to sys(1)