Motion Control of Hexacopters: A Comparative Study of Adaptive Backstepping and Sliding Mode Control With Control Allocation

Hexacopters are unmanned aerial vehicles that have three pairs of counter-rotating fixed-pitch blades. This paper assesses and compares the robust performance of two control strategies for hexacopters: an adaptive backstepping controller and a sliding mode controller. This paper also introduces a novel control allocation scheme that maintains the rotor speeds within actuator limits. Both controllers perform comparably and prove to be robust against disturbances and uncertainties. Sliding mode control surpasses adaptive backstepping control in tracking altitude, roll, and yaw, at the expense of a more chattered input under uncertainty. Meanwhile, the adaptive backstepping controller is more robust against internal disturbances. The paper concludes by providing an outlook on future work.