System Identification ⭐ Second-Order System ⭐ Step Response 💡 Calculation & MATLAB 💡 Example 4

[@aliosmanbayir6009]

Very helpful video.. But how do you get the first unit step response graph ? How do you manage your inputs ? Should I use simulink and add step button for that ?

[@CANEDUX]

You are welcome! In the simulation part, I show in MATLAB how I generate the plots. You can also use Simulink, but I prefer to use MATLAB script and command window for this case. Just let me know if you have further questions.

[@aliosmanbayir6009]

@@CANEDUX hello sir, I have a question about the evaluation of transfer function diagrams... I have a rotation spring mass system and I have obtained its 2 and 3rd dof transfer functions. What I want to ask is that is it possible I change the values of the variables of that transfer function and see the difference. For example I have a few damping coefficient values and I want to see how the different damping constants effect the system . Therefore I'm changing the damping coefficient values in Matlab then running the transfer function (the transfer function changes as well) . Second question is, what does this Amplitude (dB) really means in those plots? Is it for like deformation or velocity changes in a system ?

[@CANEDUX]

@@aliosmanbayir6009 1. You can sweep the values in MATLAB and observe what the effect is. See MATLAB site for the details. 2. The dB is the unit of the TRANSFER. What the transfer is, depends on the application. For example, your input can be force F (N) and the output can be distance x (m), thus the transfer is x/F. In addition, this transfer function can have a unit or be unitless.

[@parinya38888]

❤❤❤Thank you so much.

[@CANEDUX]

You are welcome.

[@ltd5480]

is the second order transfer function is can be used for unit step input?

[@CANEDUX]

Yes, you can use a step input for a second-order system. Also for other systems; first-order and higher order systems.

[@ltd5480]

@@CANEDUX I am having a question that the general second-order transfer function formula with zeta, omega coefficient you given there. How can you just based on the response system graph to derive the transfer function of the input of unit step function, what if the graph is ramp input or other types? G(s)=C(s)/R(s), what if input R(s) is different, is it effect the transfer function?

[@CANEDUX]

​@@ltd5480 The transfer function of the system will not change, but you cannot use every signal as an input to determine the transfer function.