Geometric Disturbance Observer Based Control for Multirotors

In this paper we propose a disturbance observer based control for the class of multirotor aerial vehicles having co-planar and collinear propellers, following a geometric approach. The control scheme is based on the well known inner-outer loop structure, where the tracking control problem on the group of rotations is extended with an observer. To prove the asymptotic stability of the tracking error, a Lyapunov stability analysis is provided, taking into account kinematics, dynamics, and disturbance observer errors. For this purpose, disturbance rejection is achieved leveraging the disturbance model, which is assumed to be generated by exogenous systems having arbitrary orders. Simulations are performed on a hexarotor under elaborate external disturbances, which take into account unmodeled dynamics and time-varying wind effects. Simulation results show that the proposed control scheme can compensate for the disturbances, even when the embedded exogenous system model is coarse, outperforming the baseline geometric controller without disturbance compensation.