Robust whole-body control of an unmanned aerial manipulator

This paper presents a cascade control strategy of an aerial manipulator, which is composed of a quadrotor unmanned aerial vehicle (UAV) serially coupled to a robotic arm. The main objective is to track a desired trajectory of the end-effector while keeping the whole system stable, in presence of uncertainties. To achieve that, the proposed cascade control system considers in the inner loop a partial feedback linearization controller (FL) obtained from Lie derivative, while considers the quadrotor UAV model with input coupling. In the outer loop a kinematic controller is designed through the linear controller using LMIs to deal with the remaining uncertainties from the FL approach. Dual quaternion algebra is used to obtain the whole-body kinematic model, and the equations of motion express the influence of the manipulator movement in the center of mass of the entire system. Finally, the performance of the proposed control strategy is evaluated through simulation of a quadrotor equipped with a 5-DOF robotic arm subject to parametric uncertainties and external disturbances.