Altitude and Attitude Stabilization of UAV Quadrotor System using Improved Active Disturbance Rejection Control

An improved active disturbance rejection control (IADRC) is proposed to stabilize and reject exogenous disturbances and system uncertainties for a 6-degree of freedom (DOF) quadrotor system. We used the nonlinear model of the 6-DOF quadrotor system to design four IADRC units for the altitude and attitude stabilization. Stability analysis is demonstrated for both the extended state observers of each IADRC unit and the overall closed-loop system using Hurwitz stability criterion. The simulations are implemented under the MATLAB environment where the parameters of the IADRC units are tuned to minimize the multi-objective output performance index. The unmanned aerial vehicle is tested with different tracking scenarios while subjected to exogenous disturbances and system parameter uncertainties. The performance of the proposed IADRC is compared with that of the PID controller, and the simulations revealed that the proposed IADRC scheme stabilized and excellently counteracted the exogenous disturbances and system uncertainties and outperformed the PID used in this work.