Tracking Control of Quadrotors Based on a High-Order Fully Actuated System Approach

This paper presents a trajectory tracking control method for quadrotors based on a high-order fully actuated (HOFA) system approach. Despite having six degrees of freedom, a quadrotor possesses only four independent control inputs, making it an under-actuated system. To resolve this, we decouple the control architecture into two cascaded subsystems: an outer position control loop and an inner attitude control loop that achieves full actuation. Leveraging the inherent properties of rotation matrix representation, we develop a HOFA model for the attitude subsystem. The subsystem is linearized by compensating the nonlinear terms and a linear quadratic regulator is then applied to the linearized system. Numerical simulations and comparative outdoor experiments demonstrate the effectiveness and superior tracking performance of the proposed controller.