Investigation of the flight performance of an unmanned aerial vehicle with quad rotor configuration using model predictive control method

Quadrotor Unmanned Aerial Vehicles (UAVs) are frequently used in sectors such as transportation, defense, and entertainment. These UAVs are often controlled using complex flight algorithms to perform complex maneuvers in changing weather conditions. In such cases, an advanced controller must be designed to observe the desired flight performance and the effect of this controller on flight performance must be examined through uncertainty analysis. This thesis study aims to explain the modelling and control of a quadrotor UAV in six degrees of freedom (6-DOF) space. In the created 6-DOF model, Monte Carlo uncertainty analysis was used to examine the flight performance of the UAV under changing weather conditions, imprecise sensor measurements and unknown aerodynamic features. Modelling and controller design were carried out using MATLAB & Simulink software. Since the modelling was done in 6-DOF space, translational dynamics modelling was performed with 3 force equations and rotational dynamics modelling was performed with 3 moment equations. A two-loop controller structure was designed based on the resulting model. There is a position controller in the outer loop of this controller and a rotation controller in the inner loop. The position controller is a state space controller that can control 2 state variables in each of the 3 axes. Controllers have been designed using the pole placement technique to control each axis of the state space type position controller separately. The rotation controller is a more complex state space controller designed to control 6 state variables together. In order to compare the performance of the system under different control techniques, the rotation controller was designed separately with Model Predictive Control, Pole Placement and Linear Quadratic Regulator (LQR) techniques. Within the designed model, each of these 3 controllers can be switched and put into use. After completing the modeling controller designs, the robustness of the controllers was examined with single runs. Additionally, deviations in desired angle, position and speed values under uncertain conditions were examined to evaluate the flight performance of the UAV. By gathering the simulation results together, the advantages of the three rotation controllers over each other were revealed. As a result, in this thesis study, the flight performance of a four-rotor UAV was examined under different control techniques.