PathFollowing and Attitude Control of a Payload Using Multiple Quadrotors This paper addresses the problem of carrying a rodshaped load between a certain origin and a desired goal using unmanned aerial vehicles (UAV). The load is carried via flexible cables by two quadrotors, one at each end of the bar. Positioning, orientation, and pathfollowing tasks are here addressed. The robots and the load are modeled as a single system, using a virtual structure framework for robot formation and a nonlinear controller based on feedback linearization to handle the load oscillations and accomplish the missions. Results obtained running a real experiment using two AR. Drone quadrotors to carry an aluminum bar are presented through illustrations and videos, which validate the proposed system.

Collaborative Transportation of CableSuspended Payload using Two Quadcopters with Human in the loop We study the problem of collaborative transportation of cablesuspended payload using two quadcopters. While previous works on transportation using quadcopters emphasize more on autonomous control and generating complex trajectory, in this paper a masterslave strategy is implemented where the master quadcopter is controlled by human and the slave quadcopter tries to stabilize the oscillations of the payload. Two quadcopters with a cablesuspended payload system is underactuated with coupled dynamics and hence, manual control is difficult. We use Lagrangian mechanics on a manifold for deriving equations of motion and apply variation based linearization to linearize the system. We designed a Lyapunov based controller to minimize the oscillations of the payload while transportation, leading to an easier manual control of master quadcopter.