Output tracking for quadrotor-based aerial manipulators

For a class of aerial manipulators given by a quadrotor aerial vehicle endowed with a robotic arm, this work focuses on the design of a feedback control strategy to let the position and the orientation of the end-effector to track a desired trajectory. Different configurations of robotic arms are taken into account so as to link the number of actuated degrees of freedom to the achievable tracking performances. In particular, when a robotic arm characterized by the minimum number of actuated joints is considered, it is shown how the presence of an offset between the point in which the manipulator is attached and the center of gravity of the vehicle may introduce some unstable internal dynamics affecting the achievable asymptotic performances. Such a limitation can be removed by properly exploiting robotic manipulators characterized by a redundant number of actuated joints. The proposed feedback control strategy is then shown to be able to exploit the mechanical layout of the manipulator so as to achieve asymptotic or practical tracking of the desired references.