Control of Quadrotor Slung Load System Based on Double ADRC

A quadrotor carrying a cable-suspended load is usually called the quadrotor slung load (QSL) system. The existence of the slung load degrades the performance of the quadrotor and even affects the stability of the closed-loop system. In this paper, the stability and trajectory tracking of the QSL system are addressed. Firstly, the system model is detailed anylized based on Newton-Euler and Euler-Lagrange methods. Then, in order to resist the impact of the load and external environmental disturbance on the quadrotor, the double active disturbance rejection control (ADRC) control strategy is proposed. The load swing is considered as external disturbance to the quadrotor. The extended state observer (ESO) is employed in the position loop and attitude loop of the controller respectively to estimate disturbance of the system. Finally, experiments are conducted to validate the stability and effectiveness of the proposed control strategy.