FREQUENCY-DOMAIN SYSTEM IDENTIFICATION OF F-16 LONGITUDINAL DYNAMICS

2022-3-10
Ergazi, Nazife Ege
The longitudinal dynamics of F-16 aircraft in a level trim, unaccelerated flight are identified using frequency-domain system identification techniques. The nonlinear system is excited by sine sweep elevator input, and angle of attack and pitch rate responses are collected. Detrending and windowing are applied to time-domain data and are converted to the frequency-domain by applying Fast Fourier Transform (FFT). The smooth spectral estimates are found from the transformed data, allowing frequency responses and coherence to be calculated. Under the guidance of coherence, transfer functions are estimated to the frequency response data. Then, nondimensional derivatives are extracted from these identified transfer functions. Finally, the identified model is verified in the time domain.

Suggestions

Active Control of Smart Fin Model for Aircraft Buffeting Load Alleviation Applications
Chen, Yong; Ulker, Fatma Demet; Nalbantoglu, Volkan; Wickramasinghe, Viresh; Zimcik, David; Yaman, Yavuz (2009-11-01)
Following the program to lest a hybrid actuation system for high-agility aircraft buffeting load alleviation oil the full-scale F/A-18 vertical fin structure, an investigation has been performed to understand the aerodynamic effects of high-speed vortical flows on the dynamic characteristics of vertical fin structures. Extensive wind-tunnel tests have been conducted on a scaled model fill integrated with piezoelectric actuators and accelerometers to measure file aft-tip vibration responses under various fre...
Multi-fidelity aerodynamic dataset generation of a fighter aircraft
Kurt, Huseyin Burak; Millidere, Murat; Gomec, Fazıl Selcuk; Uğur, Ömür (2021-01-01)
High-fidelity aerodynamic dataset generation is one of the most significant components of the aircraft flight simulation, and, it is a time consuming and costly process. Data fusion techniques suggest that, instead of using high fidelity data for entire aerodynamic dataset, an incorporating combination of high-fidelity and low-fidelity data is a more cost-effective one. The objective of data fusion is to obtain high-fidelity dataset accuracy by combining less amount of high-fidelity dataset and more amount ...
Online Dynamic Trim and Control Limit Estimation
Yavrucuk, İlkay (American Institute of Aeronautics and Astronautics (AIAA), 2012-9)
The online estimation of a maneuvering steady-state condition of an aircraft, called the dynamic trim, is used to estimate the allowable control travel during flight, a key information in pilot cueing for envelope limit protection. In this paper a new methodology is presented where adaptive models are used to estimate online local dynamic trim conditions, while requiring very limited a priori vehicle information. Adaptive neural networks are employed to enable online learning. The models are used to estimat...
DYNAMIC MODELING AND CONTROL OF AN ELECTROMECHANICAL CONTROL ACTUATION SYSTEM
Yerlikaya, Umit; Balkan, Raif Tuna (2017-10-13)
Electromechanical actuators are widely used in miscellaneous applications in engineering such as aircrafts, missiles, etc. due to their momentary overdrive capability, long-term storability, and low quiescent power/low maintenance characteristics. This work focuses on electromechanical control actuation systems (CAS) that are composed of a brushless direct current motor, ball screw, and lever mechanism. In this type of CAS, nonlinearity and asymmetry occur due to the lever mechanism itself, saturation limit...
Steady-State CFD Analysis of 3D Bio-inspired Flapping Wing Models
Bektaş, Mürvet; Kurtuluş, Dilek Funda; Güler, Mehmet Ali (2018-07-11)
The aerodynamics of insects flying at low Reynolds numbers is considered for Micro Air Vehicles (MAV) designs. The aim of this study is to analyze different flapping wing models and to predict generated forces and vortices around the wings. The analyses are significant for understanding properties of flying animals like birds, insects and for improving MAVs more. For three insect species (namely, bumblebee, hawkmoth, and hummingbird), three dimensional (3D) wing models are numerically analyzed at different ...
Citation Formats
N. E. Ergazi, “FREQUENCY-DOMAIN SYSTEM IDENTIFICATION OF F-16 LONGITUDINAL DYNAMICS,” M.S. - Master of Science, Middle East Technical University, 2022.