Robust convex LPV control of a Helicopter-UAV transporting a suspended payload

This paper develops a robust integral sliding mode controller for a helicopter-type unmanned aerial vehicle with a suspended payload. The nonlinear model is rewritten by considering a convex Linear Parameter Varying model that captures the nonlinear system dynamics. Then, a controller is developed by considering a nominal integrator comparator scheme and a discontinuous control based on sliding modes. The first part of the controller is dedicated to tracking the desired trajectory, while the second is devoted to attenuating the effect of external disturbance through a sliding surface. A set of linear matrix inequalities obtained from a Lyapunov quadratic function gives sufficient conditions to compute the controller gains. Numerical simulations are carried out to illustrate the effectiveness of the proposed approach in tracking the desired trajectory and attenuating the load oscillations under the presence of external disturbance.