Finite-time adaptive robust nonlinear control for uncertain quadrotor UAV carrying a load under external disturbances

Abstract

One of the applications of unmanned aerial vehicles (UAVs) is to transport various cargoes such as medical supplies, food, and electronic devices. Hence, a significant challenge in cargo transportation is mitigating disturbances along the trajectory, including external factors like wind and uncertainties affecting the system model. This study introduces a robust adaptive integral fast terminal sliding mode control strategy (AIFTSMC) for an uncertain quadrotor UAV carrying a load, faced with adverse external influences. The system’s integrated model is derived using the Lagrange–Euler method for the quadrotor’s translational subsystem and the load, and the Newton–Euler method for the rotational subsystem. Nonlinear and robust control methods exhibit promising potential for guiding and stabilizing this intricate and underactuated system, with sliding mode control (SMC) techniques standing out for their distinctive attributes. Designing the IFTSMC technique enables trajectory tracking and load management to reduce steady-state errors within a finite-time frame. By incorporating adaptive rules with upper-bound estimates for undesirable factors, controller consistency is enhanced. The proposed controller demonstrates robust performance within a finite time. Simulation comparisons with existing methods, sensitivity analyses to various initial conditions and load angles, unequivocally demonstrate the superior efficacy of the proposed control strategy over alternative approaches.