I have compared my transfer function with standard characteristic equation of a 2nd order system and I found out that my natural frequency is 3 radians and damping ratio (zeta) is 0.5 but how can I estimate/find and verify these values from graph/plot of MATLAB Simulink Scope?
I have also attached a snapshot, which shows two data cursors at two consecutive peaks. From those cursors, I found out approximate time period which is approximately 3 second and then from reciprocal of that time period i found out frequency, which is 0.33 Hz and then I multiply it 2 and pi but I get answer as 2.07 radians.
But my transfer function has originally natural frequency of 3 radians, why this difference?