Index exceeds the number of array elements. Index must not exceed 1.

close all;

>> clear all;

>> z=[0,0.1,0.2,0.4,0.6,0.7,0.8,0.9,1];

>> num=[0 0 75];

>> t=0:0.1:25;

>> u=ones(1,251);

>> r=t;

>> for i=1:1:9

den=[1 20*z(i) 75];

>> T=tf(num, den);

>> [y{i}]=lsim(T,r,t);

>> subplot(5,2,1);

>> plot (t,y{i},t,r);

>> title('time response of second order systemfor different values of zeta');

>> z=num2str(z(i));

>> end;

>> subplot(5,2,10);

>> plot(t,y{1},t,y{2},t,y{3},t,y{4},t,y{5},t,y{6},t,y{7},t,y{8},t,y{9});

>> axis([0 1 0 1]);

>> xlabel('time sec');

>> ylabel('amplitude');

>> title('time response for second second order systemfor different values of zeta');

>> legend ('z=0','z=0.1','z=0.2','z=0.4','z=0.6','z=0.7','z=0.8','z=0.9','z=1');

Answer 1

[Richard Stephens]

The line

z=num2str(z(i));

should be deleted: it overwrites z which becomes a single char.

It would be helpful if you submitted code without the ">>" by copying from the Command History window.