A hybrid control approach for powered parafoil combining active disturbance rejection control and unbalanced load compensation

Powered parafoil is a kind of low-speed unmanned air vehicle and is widely used in aerospace applications. However, the wind interference and the unbalanced load on the actuators of its horizontal controller extremely reduce the control effect and the disturbance rejection ability of the trajectory tracking. In order to solve these problems, a hybrid control approach for powered parafoil based on active disturbance rejection control is proposed. In this control approach, distinguished from other existing ones, the horizontal controller consists of the inner and outer loops. The outer loop is applied to accurately control the flight direction and offset the wind disturbance of the whole system. Meanwhile, the inner loop is designed to offer higher control precision and dynamically compensate the unbalanced load on the actuators of the horizontal controller. In order to verify the control approach, the model of the powered parafoil is improved by the model of rudders and flap deflection. Then, the effectiveness of the proposed control method is illustrated by the experiment. The results show that compared with the proportional–integral–derivative controller, the control effect and the anti-disturbance ability are all substantially improved.