TRAJECTORY TRACKING OF A QUADROTOR UAV USING GEOMETRIC-BASED BACKSTEPPING CONTROL

Abstract

This thesis presents a variety of dynamics and trajectory control techniques for the quadrotor. The thesis includes many ways of expressing the dynamics of the quadrotor, such as nonlinear dynamics on Euler Lagrangian and simplied linearized dynamics using small angle assumption, and various control theory, i.e. a linear controller such as PID, LQR and robust control and a nonlinear controller such as feedback linearization, backstepping, geometric control and dynamic inversion. Also, a backstepping controller based on SE(3) to track the desired trajectory for a quadrotor unmanned aerial vehicle is proposed. The proposed controller consists of two parts: 1) a position control part and 2) an attitude control part. The position controller is used to track the desired Cartesian coordinates using position and velocity errors, while the attitude controller uses the rotation matrix error and body angular velocity error to stabilize attitude dynamics expressed on SO(3). Simulation results illustrate the more stable tracking performance of the proposed controller in noisy environments in comparison with other geometric-based controllers. Experimental results on a micro quadrotor show the satisfactory performance of the proposed controller.