Flight control of VTOL quadrotor aircraft via output feedback

Abstract

In this paper, a new output feedback control system design method for a VTOL quadrotor aircraft is proposed. A nonlinear observer is developed to estimate the unmeasurable vehicle speed vector. Based on the speed estimation, a cascade control strategy consisting of a kernel loop and a reference command generator is presented for the control system design. A nonlinear approach using model reference control and control allocation techniques is proposed to design the kernel loop control. The control allocation technique adopted in this paper can handle actuator saturations and is applicable to both overactuated and underactuated systems. The designed kernel control law is in the form of dynamic update law. The reference of the kernel loop control is generated by a reference command generator consisting of attitude and position controls. Dynamic inversion method is used in the design of the reference command generator. The proposed approach is applied to a quadrotor aircraft and simulation results show the effectiveness of the proposed approach. Copyright © 2010 by the American Institute of Aeronautics American Institute of Aeronautics and Astronautics. All right reserved.