Frequency Response Estimation for Mechanical Systems Using Closed-Loop Step Response Data

Abstract

In this paper, a simple scheme to estimate frequency transfer functions of linear time-invariant single-input single-output systems based on closed-loop step response data is investigated. The method uses only a single set of step response data of plants under closed-loop operating conditions. The input and output of a plant are filtered by a simple bandpass filter, and the frequency transfer function of the plant is obtained with the Discrete Fourier Transforms of the filtered input and output signals. The method is applied to a resonant mechanical system and its validity is illustrated through simulations and experiments.