Nonlinear Control of a TiltRotor UAV for Load Transportation

Abstract

This paper proposes a nonlinear control strategy to solve the suspended load transportation problem using a Tilt-rotor Unmanned Aerial Vehicle. The aim is to maintain both the aircraft and the load stable throughout the whole trajectory, even in the presence of parametric uncertainties and measurement errors. The system modeling is obtained via Euler-Lagrange formulation considering both the dynamics of the Tilt-rotor UAV and the suspended load. A three-level cascade control strategy is proposed. Each level of the cascade system executes an input-output feedback linearization control law. A controller is designed so as to perform path tracking while also avoiding load swing. The solution is compared to a simpler controller whose design considers the load as a disturbance to the system but does not avoid its swing. Simulation results are carried out to corroborate the proposed control strategy.