I am facing the dimension error during generating the second order transfer function can any one help me please. i have attached the error pic and code as well.

filename = 'datacollect2.xlsx';
num = xlsread(filename,'B1:B60');
w = num/60;
N = length(num);
t = 1/w;
s = xlsread(filename,'B3:B3');
xt= s;
g = 1/N;
v = xlsread(filename,'B60:B60');
h = xt./ v ;
ln=@log;
q=ln(h);
zeta = g .* q;
[num,den] = ord2(w,zeta);
sys = tf(M);
step(sys)

Answer 1

[dpb]

ord2 generates the num,den for a system given the natural frequency wn (ωn) and damping factor z (ζ). It is not a vectorized function; both wn and z need to be constants. You've passed a vector for wn that can't be multiplied by itself.

Multiple values for a system natural frequency don't really make sense, anyway; if you mean to be modelling the system response as a function of changing that as a parameter you'd call ord2 in a loop with the given combination.

See the doc <ORD2> for example usage, discussion.