Quadrotor Attitude Control via Three-Loop ADRC and Backstepping Integral Method: Dynamic Modeling and Validation

Considering the dynamic characteristics of four-rotor attitude control, including nonlinearity, internal underactuation and strong coupling, this study proposes a control strategy that integrates adaptive Active Disturbance Rejection Control (ADRC) with the inverse step integration method. This approach aims to enhance adaptability to uncertain parameters and external disturbances. First, a mathematical model for the flight attitude angle of the quadrotor is formulated. The dynamics of the quadrotor is partitioned into three subsystems corresponding to the pitch, roll and yaw axes, with ADRC parameters being individually calibrated for each. Subsequently, the Extended State Observer (ESO) component of ADRC is integrated into the design of each virtual control layer, enabling real-time estimation and compensation for dynamic disturbances within the subsystems. An adaptive parameter adjustment mechanism is incorporated during the backstepping process to enhance the precision and response speed of attitude angle control. Finally, the anti-interference performance and robustness of the tri-loop cascaded ADRC controller are validated using the fusion inverse integration method on the MATLAB simulation platform. Experimental results show that, compared to the single-loop attitude control ADRC, the three-loop cascaded ADRC integrated with the backstepping integral method significantly improves the response times for the pitch, roll and yaw axes by approximately 67.7%, 69.8% and 58.4%, respectively, under the same strong interference conditions. Additionally, the average fluctuation amplitude of the angles decreases to [Formula: see text], [Formula: see text] and [Formula: see text] for the pitch, roll and yaw axes, respectively. Therefore, the backstepping integral method integrated with the three-loop cascaded ADRC not only ensures a higher response speed across all three axes but also strengthens the robustness of the quadrotor, improving angle stability by nearly a factor of 10. It offers innovative theoretical insights and technical solutions for addressing the dynamic stability control challenges in strongly nonlinear and multi-source uncertain systems.