Frequency Response Analysis for Dynamic Model Identification and Control of a Ducted Fan Aerial Vehicle in Hover

Abstract

System Identification is a key technology for the development and integration of modern engineering systems including unconventional flying vehicles. These systems are highly parametric with complex dynamics and nonlinearities. Ducted fans are special class of these vehicles that can take off vertically, hover and cruise at very low speed. In this paper, an exact equivalent linear system is found from the non-linear dynamic model of a ducted fan by use of frequency response identification. Here, power spectral density analysis is performed, using CIFER software, to evaluate the input-output responses in hover and to derive the transfer functions based on the coherence criterion. Then, PID controllers are designed by utilizing the identified transfer functions and the performance characteristics of the controllers are evaluated in fully non-linear simulation of the system.