I am trying to approximate a transfer function of a system. The system is a linear actuator, connected to a feedback potentiometer. The actuator has a mass on it. The following figure is a step response, with 24 V as input, and the potentiometer position as output.
by this, I found out it is totally impossible to approximate this system as a first or second order system. Is there a way to experimentally find an approximation(I mean transfer function) of this behavior?