Robust Control of Quadrotor using Uncertainty and Disturbance Estimation

In this paper, a robust position and attitude tracking control problem of a quadrotor subject to system nonlinearities, input coupling, aerodynamic uncertainties and external wind disturbances is investigated. An uncertainty and disturbance estimator (UDE) based robustified nonlinear dynamic inversion (NDI) control scheme is proposed for the purpose. The UDE technique robustifies the NDI based controller by providing estimate of the lumped or total disturbance thereby enabling rejection of the same. The effectiveness and benefits of the proposed scheme are confirmed through six-DOF simulations considering nonlinear quadrotor dynamics under ideal as well as perturbed flight conditions. Further, the efficacy and superiority of the proposed control scheme are validated through Monte-Carlo simulations and experimental validation on Quanser's 3-DOF Hover setup.