Based on robust sliding mode and linear active disturbance rejection control for attitude of quadrotor load UAV

In this paper, a mass adaptive control method combining with robust sliding mode control (SMC) and linear active disturbance rejection control (LADRC) is designed for the quadrotor load unmanned aerial vehicle (UAV) with mass variation. In detail, firstly, the mass variation in the quadrotor affects the position of its centroid, taking into account the changes of centroid position, which makes the established model more accurate. Moreover, a mass adaptive law is designed to eliminate the influence of mass variation. Secondly, SMC can enhance the robustness of the controller, improve the anti-disturbance performance and overcome the problem of low control precision caused by bandwidth limitation of LADRC. The linear extended state observer estimates the external disturbances of the system and the internal unmodeled dynamics caused by the SMC chattering in real time, and then, the total disturbance is compensated by the proportional-derivative controller. The proposed scheme combines the advantages of SMC and LADRC and complements each other. Thirdly, in order to simplify the parameter setting, the adaptive control is introduced in LADRC to adjust the controller parameters in real time, which is beneficial to the stability analysis of the control system. Then Lyapunov stability theory is used to prove the stability of the whole system. Finally, the simulation is compared with LADRC and dynamic surface active disturbance rejection control. The results show that the designed scheme has smaller overshoot and faster response speed, which proves its superiority. Moreover, the designed adaptive law is also effective, it can eliminate the influence of parameter deviation, so that the proposed scheme can track the reference signal stably even in the presence of disturbances.