@conference {2015e-RajRylBueFra,
	title = {Modeling, Control and Design Optimization for a Fully-actuated Hexarotor Aerial Vehicle with Tilted Propellers},
	booktitle = {2015 IEEE Int. Conf. on Robotics and Automation},
	year = {2015},
	month = {05/2015},
	pages = {4006-4013},
	address = {Seattle, WA},
	keywords = {Aerial Robotics, UAV hardware platforms},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2015e-RajRylBueFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2015e-RajRylBueFra.mp4},
	author = {Sujit Rajappa and Markus Ryll and Heinrich H. B{\"u}lthoff and Antonio Franchi}
}
@conference {2014e-SteBasBueFra,
	title = {A Semi-autonomous UAV Platform for Indoor Remote Operation with Visual and Haptic Feedback},
	booktitle = {2014 IEEE Int. Conf. on Robotics and Automation},
	year = {2014},
	month = {05/2014},
	pages = {3862-3869},
	address = {Hong Kong, China},
	abstract = {We present the development of a semi-autonomous quadrotor UAV platform for indoor teleoperation using RGB- D technology as exteroceptive sensor. The platform integrates IMU and Dense Visual Odometry pose estimation in order to stabilize the UAV velocity and track the desired velocity commanded by a remote operator though an haptic inter- face. While being commanded, the quadrotor autonomously performs a persistent pan-scanning of the surrounding area in order to extend the intrinsically limited field of view. The RGB-D sensor is used also for collision-safe navigation using a probabilistically updated local obstacle map. In the operator visual feedback, pan-scanning movement is real time compensated by an IMU-based adaptive filtering algorithm that lets the operator perform the drive experience in a oscillation- free frame. An additional sensory channel for the operator is provided by the haptic feedback, which is based on the obstacle map and velocity tracking error in order to convey information about the environment and quadrotor state. The effectiveness of the platform is validated by means of experiments performed without the aid of any external positioning system.},
	keywords = {Aerial Robotics, Localization of aerial robots, UAV hardware platforms},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2014e-SteBasBueFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2014e-SteBasBueFra.mp4},
	author = {Paolo Stegagno and Massimo Basile and Heinrich H. B{\"u}lthoff and Antonio Franchi}
}
@conference {2014b-GioRylPraBueFra,
	title = {Turning a Near-hovering Controlled Quadrotor into a 3D Force Effector},
	booktitle = {2014 IEEE Int. Conf. on Robotics and Automation},
	year = {2014},
	month = {05/2014},
	pages = {6278-6284},
	address = {Hong Kong, China},
	abstract = {In this paper the problem of a quadrotor that physically interacts with the surrounding environment through a rigid tool is considered. We present a theoretical design that allows to exert an arbitrary 3D force by using a standard near-hovering controller that was originally developed for contact-free flight control. This is achieved by analytically solving the nonlinear system that relates the quadrotor state, the force exerted by the rigid tool on the environment, and the near-hovering controller action at the equilibrium points, during any generic contact. Stability of the equilibria for the most relevant actions (pushing, releasing, lifting, dropping, and left-right shifting) are proven by means of numerical analysis using the indirect Lyapunov method. An experimental platform, including a suitable tool design, has been developed and used to validate the theory with preliminary experiments.},
	keywords = {Aerial Physical Interaction, Aerial Robotics, UAV hardware platforms},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2014b-GioRylPraBueFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2014b-GioRylPraBueFra.mp4},
	author = {Guido Gioioso and Markus Ryll and Domenico Prattichizzo and Heinrich H. B{\"u}lthoff and Antonio Franchi}
}
@conference {2013o-SpiRobRylBueFra,
	title = {An Open-Source Hardware/Software Architecture for Quadrotor UAVs},
	booktitle = {2nd IFAC Workshop on Research, Education and Development of Unmanned Aerial Systems},
	year = {2013},
	month = {11/2013},
	address = {Compiegne, France},
	abstract = {In this paper, we illustrate an open-source ready-to-use hardware/software architecture for a quadrotor UAV. The presented platform is price effective, highly customizable, and easily exploitable by other researchers involved in high-level UAV control tasks and for educational purposes as well. The use of object-oriented programming and full support of Robot Operating System (ROS) and Matlab Simulink allows for an efficient customization, code reuse, functionality expansion and rapid prototyping of new algorithms. We provide an extensive illustration of the various UAV components and a thorough description of the main basic algorithms and calibration procedures. Finally, we present some experimental case studies aimed at showing the effectiveness of the proposed architecture.},
	keywords = {Aerial Robotics, UAV hardware platforms},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2013o-SpiRobRylBueFra-preprint.pdf},
	author = {Riccardo Spica and Paolo Robuffo Giordano and Markus Ryll and Heinrich H. B{\"u}lthoff and Antonio Franchi}
}
@conference {2013q-SteBasBueFra,
	title = {RGB-D based Haptic Teleoperation of UAVs with Onboard Sensors: Development and Preliminary Results},
	booktitle = {2013 IROS Work. on Vision-based Closed-Loop Control and Navigation of Micro Helicopters in GPS-denied Environments},
	year = {2013},
	month = {11/2013},
	address = {Tokyo, Japan},
	keywords = {Aerial Robotics, UAV hardware platforms},
	author = {Paolo Stegagno and Massimo Basile and Heinrich H. B{\"u}lthoff and Antonio Franchi}
}
@article {2013b-LeeFraSonBueRob,
	title = {Semi-Autonomous Haptic Teleoperation Control Architecture of Multiple Unmanned Aerial Vehicles},
	journal = {IEEE/ASME Transaction on Mechatronics, Focused Section on Aerospace Mechatronics},
	volume = {18},
	year = {2013},
	month = {08/2013},
	pages = {1334-1345},
	abstract = {We propose a novel semi-autonomous haptic teleoperation control architecture for multiple unmanned aerial vehicles (UAVs), consisting of three control layers: 1) UAV control layer, where each UAV is abstracted by, and is controlled to follow
the trajectory of, its own kinematic Cartesian virtual point (VP); 2) VP control layer, which modulates each VP{\textquoteright}s motion according to the teleoperation commands and local artificial potentials (for VP-VP/VP-obstacle collision avoidance and VP-VP connectivity preservation); and 3) teleoperation layer, through which a single remote human user can command all (or some) of the VPs{\textquoteright} velocity while haptically perceiving the state of all (or some) of the UAVs and obstacles. Master-passivity/slave-stability and some asymptotic performance measures are proved. Experimental results using four custom-built quadrotor-type UAVs are also presented to illustrate the theory.},
	keywords = {Bilateral Shared Control of Mobile Robots, Motion control of multiple robots, UAV hardware platforms},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2013b-LeeFraSonBueRob.pdf},
	author = {Dongjun Lee and Antonio Franchi and Hyoung Il Son and Heinrich H. B{\"u}lthoff and Paolo Robuffo Giordano}
}
@conference {2013j-GraRieBueRobFra,
	title = {The TeleKyb Framework for a Modular and Extendible ROS-based Quadrotor Control},
	booktitle = {6th European Conference on Mobile Robots},
	year = {2013},
	month = {09/2013},
	address = {Barcelona, Spain},
	abstract = {The free and open source Tele-Operation Platform of the MPI for Biological Cybernetics (TeleKyb) is an end- to-end software framework for the development of bilateral teleoperation systems between human interfaces (e.g., haptic force feedback devices or gamepads) and groups of quadrotor Unmanned Aerial Vehicles (UAVs). Among drivers for devices and robots from various hardware manufactures, TeleKyb provides a high-level closed-loop robotic controller for mobile robots that can be extended dynamically with modules for state estimation, trajectory planning, processing, and tracking. Since all internal communication is based on the Robot Operating System (ROS), TeleKyb can be easily extended to meet future needs. The capabilities of the overall framework are demonstrated in both an experimental validation of the controller for an individual quadrotor and a complex experimental setup involving bilateral human-robot interaction and shared formation control of multiple UAVs.},
	keywords = {Middleware for robotics, UAV hardware platforms},
	url = {http://www.ros.org/wiki/telekyb},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2013j-GraRieBueRobFra-preprint.pdf},
	author = {Volker Grabe and Martin Riedel and Heinrich H. B{\"u}lthoff and Paolo Robuffo Giordano and Antonio Franchi}
}
@conference {2012h-RieFraRobBueSon,
	title = {Experiments on Intercontinental Haptic Control of Multiple UAVs},
	booktitle = {12th Int. Conf. on Intelligent Autonomous Systems},
	year = {2012},
	month = {06/2012},
	pages = {227-238},
	address = {Jeju Island, Korea},
	abstract = {In this paper we propose and experimentally validate a bilateral teleoperation framework where a group of UAVs are controlled over an unreliable network with typical intercontinental time delays and packet losses. This setting is meant to represent a realistic and challenging situation for the stability the bilateral closed-loop system.
In order to increase human telepresence, the system provides the operator with both a video stream coming from the onboard cameras mounted on the UAVs, and with a suitable haptic cue, generated by a force-feedback device, informative of the UAV tracking performance and presence of impediments on the remote site.

In addition to the theoretical background, we describe the hardware and software implementation of this intercontinental teleoperation: this is composed of a semi-autonomous group of multiple quadrotor UAVs, a 3-DOF haptic interface, and a network connection based on a VPN tunnel between Germany and South Korea. The whole software framework is based upon the Robotic Operating System (ROS) communication standard.},
	keywords = {Bilateral Shared Control of Mobile Robots, Haptics, Middleware for robotics, Multi-robot systems, Teleoperation, UAV hardware platforms},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2012h-RieFraRobBueSon.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2012h-RieFraRobBueSon.mp4},
	author = {Martin Riedel and Antonio Franchi and Heinrich H. B{\"u}lthoff and Paolo Robuffo Giordano and Hyoung Il Son}
}
@booklet {2012q-RieFraBueRob,
	title = {Intercontinental Haptic Control and Advanced Supervisory Interfaces for Groups of Multiple UAVs},
	howpublished = {5th Int. Work. on Human-Friendly Robotics},
	year = {2012},
	month = {10/2012},
	address = {Bruxelles, Belgium},
	keywords = {Bilateral Shared Control of Mobile Robots, Middleware for robotics, Motion control of multiple robots, UAV hardware platforms},
	author = {Martin Riedel and Heinrich H. B{\"u}lthoff and Antonio Franchi and Paolo Robuffo Giordano}
}
@article {2012f-FraSecRylBueRob,
	title = {Shared Control: Balancing Autonomy and Human Assistance with a Group of Quadrotor UAVs.},
	journal = {IEEE Robotics and Automation Magazine, Special Issue on Aerial Robotics and the Quadrotor Platform},
	volume = {19},
	year = {2012},
	month = {09/2012},
	pages = {57-68},
	abstract = {In this paper, we present a complete control framework and associated experimental testbed for the bilateral shared control of a group of quadrotor UAVs. This control architecture is applicable to any task and allows to integrate: i) a decentralized topological motion control (responsible for the mutual interactions in the UAV formation), ii) a human assistance module (allowing human intervention, whenever needed, on some aspects of the UAV group behavior), and iii) a force-feedback possibility (increasing the telepresence of the human assistants by providing suitable haptic cues informative of the UAV behavior). 
We will show, as worked-out case studies, how to specialize the topological motion controller to the relevant cases of constant, unconstrained and connected group topologies, and how to let a human operator intervening at the level of single UAVs or of the whole group dynamics.
A detailed description of the experimental testbed is also provided with emphasis on the quadrotor UAV hardware and software architectures. Finally, the versatility of the proposed framework is demonstrated by means of experiments with real UAVs. Although quadrotors are used as actual robotic platforms, the proposed framework can be straightforwardly extended to many different kinds of UAVs with similar motion characteristics.},
	keywords = {Bilateral Shared Control of Mobile Robots, Decentralized control, Force feedback, Formation control, Haptics, Middleware for robotics, Motion control of multiple robots, Multi-robot systems, UAV hardware platforms},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2012f-FraSecRylBueRob-preprint.pdf},
	author = {Antonio Franchi and Cristian Secchi and Markus Ryll and Heinrich H. B{\"u}lthoff and Paolo Robuffo Giordano}
}
