System identification of aerodynamic derivatives for VTOL UAV

• Main Author: Matiin Muhammad Hanifah Marican
• Other Authors: Basman Elhadidi
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Aeronautical engineering
• Online Access: https://hdl.handle.net/10356/150919
• Institution: Nanyang Technological University

The establishment of an Aircraft Dynamic Model is a prerequisite to design navigation and control systems. However, aerodynamic models are not easily obtained for small- scaled aircraft model such as Unmanned Aerial Vehicles (UAVs) Simulated models are important towards the development of effective and predictive control, given that they rely on all the aerodynamic parameters to provide information on flight characteristics. There many ways to obtain the system identification of aerodynamic derivatives. Traditionally, aircraft and rotorcraft dynamic system models have been analytically determined using Newton’s Second Law for rigid-body dynamics [1]. Longitudinal aerodynamic derivatives for a simplified UAV model was measured experimentally. The model was constrained to pitch freely while mounted on a rig placed within a wind tunnel test section. A servo motor was used to provide controlled inputs to the elevator, and an Inertial Measurement Unit (IMU) was used to measure the pitch angle and pitch rate. Experiment data were collected for various elevator deflection angles, with a varied 3211 input time pulse, at a wind tunnel speed of 7.3 m/s. The data was processed using Least Squares Method and System Identification Toolkit to obtain the transfer function of the model from which aerodynamic derivatives ! and " were calculated and analysed. Results obtained from the experiment through System Identification Toolkit were similar to theoretically calculated aerodynamic derivatives. Further research can be done to expand on multiple degrees of freedom test while taking into account limitations and recommendations discussed in this report.