Model-free observer for state estimation applied to a quadrotor

In this paper, the Nonlinear Model-Free Observer (NMFO) is proposed to estimate the states of the quadrotor vehicle. NMFO is an integrated structure of the Model-Free technique and the nonlinear Thau observer. The Thau observer will accommodate for the nonlinearities in the quadrotor model and MFO will compensate for the un-modeled dynamics, modeling errors, and the system uncertainties. Flight test results have validated the proposed observer performance towards fault-free and actuator fault conditions.