Toward Aerial Grasping and Manipulation with Multiple UAVs

In this paper, a multiple UAVs control scheme is developed considering the full nonlinear position/orientation model of a j-Quadrotor system. A novel second order sliding mode controller is presented which guarantees exponential and robust tracking of admissible time-varying pose. The harmful chattering is not involved and no dynamic model is required to implement the controller to yield fast and precise tracking. Additionally, well-posed terminal and controlled time convergence allows an enforced contact at given pre-defined stable contact points at the same time. A stiffness control is proposed for grasping objects considering virtual linkages approach. Our approach yields high performance from the control system, in contrast to other simple controllers proposed for load carrying. In this sense, our advanced nonlinear control solves the apparent limitations imposed by the available technology from the viewpoint of the precise tracking control, and control of the inherent unstable underactuated dynamics, for frictionless contact points (neither rolling nor sliding are considered). A numerical simulation study, under various conditions, shows the numerical feasibility of the proposed approach.