Fast Terminal Sliding Mode Control for Quadrotor Based on ESO

This work tackles the problem of controlling unmanned aerial vehicles subject to model uncertainties and perturbations. In this paper, a series of sliding mode controllers are designed to achieve the position tracking of the quadrotor under the conditions of model uncertainties and perturbations. First, a backstepping sliding mode position controller and a fast terminal sliding mode attitude controller based on extended state observer (ESO) are designed. The sum perturbation is observed in real time using the extended state observer (ESO) and compensated in the sliding mode controller. The fast terminal controller designed in this paper avoids the singularity problem of terminal sliding mode control and effectively reduces the chattering phenomenon. Furthermore, the stability of the closed-loop system is proved by designing a suitable Lyapunov function. Comparative simulation results are shown to demonstrate the effectiveness of the proposed controller.