Development of a simulator and fractional controller for a UAV in the case of a non-linear aerodynamic model based on experimental data

In this thesis the development of a simulator and a fractional order controller of a fixed wing UAV is considered. The aerodynamic model studied is non linear and it is obtained through experimental data concerning a real and operating aircraft. The controller disegned and tuned in this work is a fractional order PI, with the final aim to compare it with its integer order counterpart in presence of different disturbances. After a brief introduction, the concepts needed to understand the fractional controller theory are presented, such as the basis of fractional calculus, with the commonly used fractional derivative definitions, the approximation method used in this work, the definition of the FOPID controller and, finally, the learining of a software package useful for the implementation of the fractional controller in MATLAB/Simulink environment. After having presented the mathematical model of the fixed wing UAV, the full simulator, developed on the MATLAB/Simulink environment and used throughout the whole thesis, is shown. Then the design and the tuning process of a FOPI controller, connected to the altitude autopilot and regarding the variation of the engine shaft angular rate, is introduced. Finally, the effectiveness and robustness of the two controllers, FOPI and PI, are compared by simulations in different conditions of disturbance.