@article {2019i-RosTogCarSchCorFra,
	title = {Cooperative Aerial Load Transportation via Sampled Communication},
	journal = {IEEE Control Systems Letters},
	volume = {4},
	year = {2019},
	month = {06/2019},
	pages = {277-282},
	abstract = {In this work, we propose a feedback-based motion planner for a class of multi-agent manipulation systems with a sparse kinematics structure. In other words, the agents are coupled together only by the transported object. The goal is to steer the load into a desired configuration. We suppose that a global motion planner generates a sequence of desired configurations that satisfy constraints as obstacles and singularities avoidance. Then, a local planner receives these references and generates the desired agents velocities, which are converted into force inputs for the vehicles. We focus on the local planner design both in the case of continuously available measurements and when they are transmitted to the agents via sampled communication. For the latter problem, we propose two strategies. The first is the discretization of the continuous-time strategy that preserves  stability and guarantees exponential convergence regardless of the sampling period. In this case, the planner gain is static and computed off-line. The second strategy requires to collect the measurements from all sensors and to solve online a set of differential equations at each sampling period. However, it has the advantage to provide doubly exponential convergence. Numerical simulations of these strategies are provided for the cooperative aerial manipulation of a cable-suspended load.},
	doi = {10.1109/LCSYS.2019.2924413},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2019i-RosTogCarSchCorFra.pdf},
	author = {Enrica Rossi and Marco Tognon and Ruggero Carli and Luca Schenato and Juan Cort{\'e}s and Antonio Franchi}
}
@conference {2016i-TogTesRosFra,
	title = {Takeoff and Landing on Slopes via Inclined Hovering with a Tethered Aerial Robot},
	booktitle = {2016 IEEE/RSJ Int. Conf. on Intelligent Robots and Systems},
	year = {2016},
	month = {10/2016},
	pages = {1702-1707},
	address = {Daejeon, South Korea},
	abstract = {In this paper we face the challenging problem of takeoff and landing on sloped surfaces for a VTOL aerial vehicle. We define the general conditions for a safe and robust maneuver and we analyze and compare two classes of methods to fulfill these conditions: free-flight vs. passively tethered. Focusing on the less studied tethered method, we show its advantages w.r.t. the free-flight method thanks to the possibility of inclined hovering equilibria. We prove that the tether configuration and the inclination of the aerial vehicle w.r.t. the slope are flat outputs of the system and we design a hierarchical nonlinear controller based on this property. We then show how this controller can be used to land and takeoff in a robust way without the need of either a planner or a perfect tracking. The validity and applicability of the method in the real world is shown by experiments with a quadrotor that is able to perform a safe landing and takeoff on a sloped surface.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2016i-TogTesRosFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2016i-TogTesRosFra_0.mp4},
	author = {Marco Tognon and Andrea Testa and Enrica Rossi and Antonio Franchi}
}
