Agile flight for a quadrotor via robust geometry control: Theory and experimental verification.

This article investigates the agile flight control design for a quadrotor unnamed aerial vehicle in the 3D environment. Due to the need for the high speed flight and aggressive manoeuver in practical scenarios, the kinematic and dynamic models of the unmanned quadrotor are described in SO(3) and the controller is designed in the rotation format, which can avoid the singularity in the Euler angle format and the unwinding issue in the quaternion format. Moreover, comparing with the other existing nonlinear control strategies for the unmanned quadrotor, the proposed controller has the advantage of easy implementation and good robustness to the modeling uncertainties and unknown external disturbances by using the robust‐integral‐signum‐error method. The stability of the closed loop system is proved via the Lyapunov based stability analysis, and the proposed nonlinear robust controller can guarantee the asymptotic convergence of the quadrotor's attitude and position tracking errors. The effectiveness of the proposed agile flight control design is validated via real‐time experiments in comparison with the classical cascaded PID controller. And the experimental results show that the proposed controller achieves much higher flight control accuracy in agile flights. [ABSTRACT FROM AUTHOR]