Quadrotor position control using cascaded adaptive integral backstepping controllers

This paper proposes a nonlinear control technique to control the position of the Qball-X4 quadrotor using a cascaded methodology of two Adaptive Integral Backstepping Controllers (AIBC). The nonlinear algorithm uses the principle of Lyapunov methodology in the backstepping technique to ensure the stability of the vehicle, and utilizes the integral action to eliminate the steady state error that caused by the disturbances and model uncertainties, as well as, the adaptation law will estimate the modeling errors caused by assumptions in simplifying the complexity of the quadrotor model. The algorithm goes through two stages of cascaded AIBCs; the first stage aims to stabilize the attitude and the altitude of the quadrotor, and the second stage feeds the first stage with the desired attitude values to control the position of the quadrotor.Flight test results show that the proposed algorithm is capable of controlling the position of the nonlinear quadrotor model.