Leader/Follower Force Control of Aerial Manipulators

This article focuses on the modeling and controlling of Unmanned Aerial Manipulators (UAMs) in a leader/follower configuration performing a cooperative manipulation task. Each UAM consists of an Unmanned Aerial Vehicle (UAV) with an attached serial-link robotic manipulator. The Recursive Newton-Euler dynamics formulation is employed to account for the interaction between the UAV and its manipulator. The overall system consists of a couple UAMs with a carrying load. The coupling between these systems is due to the exerted forces by their manipulators through the object characterized by its stiffness matrix. A leader/follower control scheme is employed with a stability-analysis tailored to the UAM-pair. The leader UAM defines the trajectory of the moving object while the follower acts so as to reduce the system's internal reaction forces. Simulation studies are employed to validate the controller's performance while comparing the system's response against that derived from a classical nonlinear tracking controller.