Transportation of an Unknown Cable-Suspended Payload by a Quadrotor in Windy Environment under Aerodynamics Effects

In this article, the aerial load transportation of an unknown slung payload in a windy environment is investigated. First, a full dynamics of the load and quadrotor is derived through the Euler-Lagrange method where the rotational and transitional drag forces are considered. Then, a robust sliding mode control is designed for the transitional movements to cope with both disturbances such as the wind forces and payload swings, and uncertainties such as the length of the cable and the mass of the load. In addition, the PD control method is presented for the quadrotor attitude control. Finally, numerical results show that the appropriate performance of the controllers during the transporting mission despite disturbances. Moreover, the Dryden wind model is utilized to model the real condition of wind velocity.