Robust trajectory tracking control of uncertain quadrotors without linear velocity measurements

In this paper, robust trajectory tracking control problem for quadrotors is investigated. The control gain is to improve the tracking performance of the closed-loop control system under the effects of multiple uncertainties. The vertical, lateral, longitudinal, and yaw motions of the quadrotor are required to track desired trajectories simultaneously. A position controller is designed to achieve the trajectory tracking and produce the desired references for the pitch and roll angles. An attitude controller is designed to stabilize the three Euler angles and an observer is applied to estimate the linear velocities which cannot be measured directly. The robust tracking performance of the overall closed-loop control system can be guaranteed. Simulation results are presented to demonstrate the effectiveness of the proposed closed-loop control system.