Modelling, identification, and control of a quadrotor helicopter

In this dissertation, we focused on the study of an autonomous flight control of quadrotor helicopter. Robust nonlinear control design strategies using observer-based control are developed, which are capable of achieving reliable and accurate tracking control for quadrotor UAV containing dynamic uncertainties, external disturbances. In order to ease readability of this dissertation, detailed explanations of the mathematical model of quadrotor UAV is provided, including the Newton-Euler formalism, Lyapunov-based stability analysis methods, sliding mode control (SMC) and backstepping fundamentals, and observer-based nonlinear control tools. The tracking control problem of a quadrotor in the presence of model uncertainties and external disturbances is investigated. Particularly, this dissertation presents the design and experimental implementation of nonlinear controller of quadrotor with observer to estimate the uncertainties and external disturbances to meet the desired control objectives. Based on a nonlinear model which considers basic aerodynamic forces and external disturbances, the quadrotor UAV model is simulated to perform a variety of maneuvering such as take-off, landing, smooth translation and horizontal and circular trajectory motions. Backstepping and sliding mode techniques combined with observers are studied, tested and compared. Simulation and a real platform were developed to prove the ability of the observer-based controller to successfully perform certain missions in the presence of unknown external disturbances and can obtain good and satisfactory estimation

A Hierarchical Tracking Controller for Quadrotor Without Linear Velocity Measurements

This chapter deals with the position control of quadrotor unmanned aerial vehicle (UAV) when quadrotor’s linear velocity is unavailable. We propose a hierarchical tracking controller for quadrotor UAV. The proposed controller does not require measurements of linear velocity of quadrotor. A nonlinear filter that avoids the need for measurements of linear velocity has proposed such that a global stability result is obtained for the position tracking error. However, backstepping based on barrier Lyapunov function has been used for the attitude controller. The control design is achieved by means of the hierarchical control, that is, design the position controller and attitude controller separately. This allows us to choose different nonlinear techniques for each controller