@article {2022d-SanTogJimCorFra,
	title = {Indirect Force Control of a Cable-suspended Aerial Multi-Robot Manipulator},
	journal = {IEEE Robotics and Automation Letters},
	volume = {7},
	year = {2022},
	month = {07/2022},
	pages = {6726-6733},
	doi = {10.1109/LRA.2022.3176457},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2022d-SanTogJimCorFra.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2022d-SanTogJimCorFra-video.mp4},
	author = {Dario Sanalitro and Marco Tognon and Anotnio-Enrique Jimenez-Cano and Juan Cort{\'e}s and Antonio Franchi}
}
@conference {2021k-CorJacJimAfiSidFra,
	title = {A General Control Architecture for Visual Servoing and Physical Interaction Tasks for Fully-actuated Aerial Vehicles},
	booktitle = {2021 Aerial Robotic Systems Physically Interacting with the Environment (AIRPHARO)},
	year = {2021},
	month = {Oct.},
	address = {Biograd na Moru, Croatia},
	author = {Gianluca Corsini and Martin Jacquet and Antonio-Enrique Jimenez-Cano and Amr Afifi and Daniel Sidobre and Antonio Franchi}
}
@conference {2021h-CoeSarLeeBalFraKonOtt,
	title = {Hierarchical Control of Redundant Aerial Manipulators with Enhanced Field of View},
	booktitle = {2021 Int. Conf. on Unmanned Aircraft Systems},
	year = {2021},
	month = {Sep.},
	address = {Athens, Greece},
	author = {Andre Coelho and Yuri Sarkisov and Jongseok Lee and Ribin Balachandran and Antonio Franchi and Konstantin Kondak and Christian Ott}
}
@article {2021b-CoeSarWu_MisSinDieFraKonOtt,
	title = {Whole-Body Teleoperation and Shared Control of Redundant Robots with Applications to Aerial Manipulation},
	journal = {Journal of Intelligent \& Robotic Systems},
	volume = {102},
	year = {2021},
	doi = {10.1007/s10846-021-01365-7},
	author = {Andre Coelho and Yuri Sarkisov and Xuwei Wu and Hrishik Mishra and Harsimran Singh and Alexander Dietrich and Antonio Franchi and Konstantin Kondak and Christian Ott}
}
@article {2020b-SanSavTogCorFra,
	title = {Full-pose Manipulation Control of a Cable-suspended load with Multiple UAVs under Uncertainties},
	journal = {IEEE Robotics and Automation Letters},
	volume = {5},
	year = {2020},
	month = {04/2020},
	pages = {2185-2191},
	abstract = {In this work, we propose an uncertainty-aware controller for the Fly-Crane system, a statically rigid cable-suspended aerial manipulator using the minimum number of aerial robots and cables. The force closure property of the Fly- Crane makes it ideal for applications where high precision is required and external disturbances should be compensated. The proposed control requires the knowledge of the nominal values of a minimum number of uncertain kinematic parameters, thus simplifying the identification process and the controller implementation. We propose an optimization-based tuning method of the control gains that ensures stability despite parameter uncertainty and maximizes the H$\infty$ performance. The validity of the proposed framework is shown through real experiments.},
	doi = {10.1109/LRA.2020.2969930},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020b-SanSavTogCorFra.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020b-SanSavTogCorFra.mp4},
	author = {Dario Sanalitro and Heitor J. Savino and Marco Tognon and Juan Cort{\'e}s and Antonio Franchi}
}
@article {2020e-MicCenZacFra,
	title = {Hierarchical nonlinear control for multi-rotor asymptotic stabilization based on zero-moment direction},
	journal = {Automatica},
	year = {2020},
	abstract = {
We consider the hovering control problem for a class of multi-rotor aerial platforms with generically oriented propellers, characterized by intrinsically coupled translational and rotational dynamics. In doing this, we first discuss some assumptions guaranteeing the rejection of generic disturbance torques while compensating for the gravity force. These assumptions are translated into a geometric condition usually satisfied by both standard models and more general configurations. Then, we propose a control strategy based on the identification of a zero-moment direction for the exerted force and a dynamic state feedback linearization based on this preferential direction, which locally asymptotically stabilizes the platform to a static hovering condition. Stability properties of the control law are rigorously proved through Lyapunov-based methods and reduction theorems for the stability of nested sets. Asymptotic zeroing of the error dynamics and convergence to the static hovering condition are then confirmed by simulation results on a star-shaped hexarotor model with tilted propellers.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020e-MicCenZacFra.pdf},
	author = {Giulia Michieletto and Angelo Cenedese and Luca Zaccarian and Antonio Franchi}
}
@conference {2020h-PetSanTogMilCorFra,
	title = {Inertial Estimation and Energy-Efficient Control of a Cable-suspended Load with a Team of UAVs},
	booktitle = {2020 Int. Conf. on Unmanned Aircraft Systems},
	year = {2020},
	month = {07/2020},
	address = {Athens, Greece},
	abstract = {The Fly-Crane is a multi-robot aerial manipulator system composed of three aerial vehicles towed to a platform by means of six cables. This paper presents a method to estimate the mass and the position of the center of mass of a loaded platform (i.e. the Fly-Crane platform including a transported load). The precise knowledge of these parameters allows to sensibly minimize the total effort exerted during a full-pose manipulation task The estimation is based on the measure of the forces applied by the aerial vehicles to the platform in different static configurations. We demonstrate that only two different configurations are sufficient to estimate the inertial parameters. Far-from-ideal numerical simulations show the effectiveness of the estimation method. Once the parameters are estimated, we show the enhancement of the system performances by minimizing the total exerted effort. The validity of the proposed algorithm in non-ideal conditions is presented through simulations based on the Gazebo simulator.},
	doi = {10.1109/ICUAS48674.2020.9213842},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020h-PetSanTogMilCorFra.pdf},
	author = {Antonio Petitti and Dario Sanalitro and Marco Tognon and A. Milella and Juan Cort{\'e}s and Antonio Franchi}
}
@article {2020l-BicMazFarCarFra,
	title = {Nonlinear Model Predictive Control with Enhanced Actuator Model for Multi-Rotor Aerial Vehicles with Generic Designs},
	journal = {Journal of Intelligent and Robotic Systems},
	volume = {100},
	year = {2020},
	pages = {1213-1247},
	abstract = {In this paper, we propose, discuss, and validate an online Nonlinear Model Predictive Control (NMPC) method for multi-rotor aerial systems with arbitrarily positioned and oriented rotors which simultaneously addresses the local ref- erence trajectory planning and tracking problems. This work brings into question some common modeling and control design choices that are typically adopted to guarantee ro- bustness and reliability but which may severely limit the at- tainable performance. Unlike most of state of the art works, the proposed method takes advantages of a unified nonlinear model which aims to describe the whole robot dynamics by explicitly including a realistic physical description of the ac- tuator dynamics and limitations. As a matter of fact, our so- lution does not resort to common simplifications such as: 1) linear model approximation, 2) cascaded control paradigm used to decouple the translational and the rotational dynam- ics of the rigid body, 3) use of low-level reactive trackers for the stabilization of the internal loop, and 4) unconstrained optimization resolution or use of fictitious constraints. More in detail, we consider as control inputs the derivatives of the propeller forces and propose a novel method to suit- ably identify the actuator limitations by leveraging experi- mental data. Differently from previous approaches, the con- straints of the optimization problem are defined only by the real physics of the actuators, avoiding conservative {\textendash} and often not physical {\textendash} input/state saturations which are present, e.g., in cascaded approaches. The control algorithm is im- plemented using a state-of-the-art Real Time Iteration (RTI) scheme with partial sensitivity update method. The perfor- mances of the control system are finally validated by means of real-time simulations and in real experiments, with a large spectrum of heterogeneous multi-rotor systems: an under- actuated quadrotor, a fully-actuated hexarotor, a multi-rotor with orientable propellers, and a multi-rotor with an unex- pected rotor failure. To the best of our knowledge, this is the first time that a predictive controller framework with all the valuable aforementioned features is presented and exten- sively validated in real-time experiments and simulations},
	doi = {10.1007/s10846-020-01250-9},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020l-BicMazFarCarFra.pdf},
	author = {Davide Bicego and Jacopo Mazzetto and Marcello Farina and Ruggero Carli and Antonio Franchi}
}
@conference {2020c-JacCorBicFra,
	title = {Perception-constrained and Motor-level Nonlinear MPC for both Underactuated and Tilted-propeller UAVs},
	booktitle = {2020 IEEE Int. Conf. on Robotics and Automation},
	year = {2020},
	month = {05/2020},
	address = {Paris, France},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020c-JacCorBicFra.mp4 , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020c-JacCorBicFra-preprint.pdf},
	author = {Martin Jacquet and Gianluca Corsini and Davide Bicego and Antonio Franchi}
}
@article {2019h-RylMusPieCatAntCacFra,
	title = {6D Interaction Control with Aerial Robots: The Flying End-Effector Paradigm},
	journal = {The International Journal of Robotics Research},
	volume = {38},
	year = {2019},
	pages = {1045-1062},
	doi = {10.1177/0278364919856694},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2019h-RylMusPieCatAntCacFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2019h-RylMusPieCatAntCacFra-1.mp4 , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2019h-RylMusPieCatAntCacFra-2.mp4 , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2019h-RylMusPieCatAntCacFra-3.mp4},
	author = {Markus Ryll and Giuseppe Muscio and Francesco Pierri and Elisabetta Cataldi and Gianluca Antonelli and Fabrizio Caccavale and Davide Bicego and Antonio Franchi}
}
@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 {2019j-MicCenFra,
	title = {Force-Moment Decoupling and Rotor-Failure Robustness for Star-Shaped Generically-Tilted Multi-Rotors},
	booktitle = {In 58th IEEE Conference on Decision and Control},
	year = {2019},
	month = {12/2019},
	address = {Nice, France},
	abstract = {Aerial robotics is increasingly becoming an at- tractive field of research thanks to the peculiar mixture of theoretical issues to be solved and technological challenges to be faced. In particular, recent developments have seen the multiplication of multi-rotor platforms that aim at improving the maneuverability of classical quadrotors in standard and harsh flying conditions, thus opening the field to compre- hensive studies over the structural multi-rotor properties of actuation, decoupling, and robustness, which strongly depend on the mechanical configuration of the systems. This work collocates along this line of research by considering star-shaped generically-tilted multi-rotors (SGTMs), namely platforms with more than four possibly tilted propellers (along two tilting orthogonal axes). For these platforms, we investigate how the structural choices over the number of propellers and the tilting angles affect the force-moment decoupling features and, by recalling the robustness definition that refers to the hovering capabilities of the platform, we provide a robustness analysis and an hoverability assessment for SGTMs having five to eight actuators against the loss of one and two propellers.},
	author = {Giulia Michieletto and Angelo Cenedese and Antonio Franchi}
}
@article {2019e-TogTelGasSabBicMalLanSanRevCorFra,
	title = {A Truly Redundant Aerial Manipulator System with Application to Push-And-Slide Inspection in Industrial Plants},
	journal = {IEEE Robotics and Automation Letters},
	volume = {4},
	year = {2019},
	month = {04/2019},
	pages = {1846-1851},
	abstract = {We present the design, motion planning and control of an aerial manipulator for non-trivial physical interaction tasks, such as pushing while sliding on curved surfaces {\textendash} a task which is motivated by the increasing interest in autonomous non-destructive tests for industrial plants. The proposed aerial manipulator consists of a multidirectional-thrust aerial vehicle {\textendash} to enhance physical interaction capabilities {\textendash} endowed with a 2-DoFs lightweight arm {\textendash} to enlarge its workspace. This combination makes it a truly-redundant manipulator going beyond standard aerial manipulators based on collinear multi- rotor platforms. The controller is based on a PID method with a {\textquoteleft}displaced{\textquoteright} positional part that ensures asymptotic stability despite the arm elasticity. A kinodynamic task-constrained and control-aware global motion planner is used. Experiments show that the proposed aerial manipulator system, equipped with an Eddy Current probe, is able to scan a metallic pipe sliding the sensor over its surface and preserving the contact. From the measures, a weld on the pipe is successfully detected and mapped.},
	doi = {10.1109/LRA.2019.2895880},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2019e-TogTelGasSabBicMalLanSanRevCorFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2019e-TogTelGasSabBicMalLanSanRevCorFra.mp4},
	author = {Marco Tognon and Hermes Tello Chavez and Enrico Gasparin and Quentin Sabl{\'e} and Davide Bicego and Anthony Mallet and Marc Lany and Gilles Santi and Bernard Revaz and Juan Cort{\'e}s and Antonio Franchi}
}
@article {2017b-AntCatArrRobChiFra,
	title = {Adaptive Trajectory Tracking for Quadrotor MAVs in Presence of Parameter Uncertainties and External Disturbances},
	journal = {IEEE Trans. on Control Systems Technology},
	volume = {26},
	year = {2018},
	month = {01/2018},
	pages = {248{\textendash}254},
	abstract = {This paper presents an adaptive trajectory tracking control strategy for quadrotor Micro Aerial Vehicles (MAVs). The proposed approach, while maintaining the typical assumption of an orientation dynamics faster than the translational one, re- moves that of absence of external disturbances and of Geometric Center coincident with the Center of Mass. In particular, the trajectory tracking control law is made adaptive with respect to the presence of external forces and moments (due, e.g., to wind), and to the uncertainty of dynamic parameters such as the position of the center of mass of the vehicle. A stability analysis is provided to analytically support the proposed controller. Finally, numerical simulations and experimental evaluations, performed with a commercially-available quadrotor MAV, are provided in order to validate the performance of the proposed adaptive control strategy.},
	author = {Gianluca Antonelli and Elisabetta Cataldi and Filippo Arrichiello and Paolo Robuffo Giordano and Stefano Chiaverini and Antonio Franchi}
}
@article {2018m-OllHerFraAntKonSanVigSanTruBalAndRod,
	title = {The AEROARMS Project: Aerial Robots with Advanced Manipulation Capabilities for Inspection and Maintenance},
	journal = {IEEE Robotics and Automation Magazine, Special Issue on Floating-base (Aerial and Underwater) Manipulation},
	volume = {25},
	year = {2018},
	month = {12/2018},
	pages = {12-23},
	abstract = {This paper summarizes new aerial robotic manipu- lation technologies and methods, required for outdoor industrial inspection and maintenance, developed in the AEROARMS project. It presents aerial robotic manipulators with dual arms and multi-directional thrusters. It deals with the control systems, including the control of the interaction forces and the compliance, the teleoperation, which uses passivity to tackle the trade- off between stability and performance, perception methods for localization, mapping and inspection, and planning methods, including a new control-aware approach for aerial manipulation. Finally, it describes a novel industrial platform with multi- directional thrusters and a new arm design to increase the robustness in industrial contact inspections. The lessons learned in the application to outdoor aerial manipulation for inspection and maintenance are pointed out.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018m-OllHerFraAntKonSanVigSanTruBalAndRod-preprint_3.pdf},
	author = {Anibal Ollero and Guillermo Heredia and Antonio Franchi and Gianluca Antonelli and Konstantin Kondak and Alberto Sanfeliu and Antidio Viguria and Jose R. Martinez-de Dios and Francesco Pierri and Juan Cort{\'e}s and A. Santamaria-Navarro and Miguel A. Trujillo and Ribin Balachandran and Juan Andrade-Cetto and Angel Rodriguez}
}
@article {2018i-TogCatTelAntCorFra,
	title = {Control-Aware Motion Planning for Task-Constrained Aerial Manipulation},
	journal = {IEEE Robotics and Automation Letters, Special Issue on Aerial Manipulation},
	volume = {3},
	year = {2018},
	note = {Also selected for presentation at the 2018 IEEE Int. Conf. on Robotics and Automation, Brisbane , Australia},
	month = {02/2018},
	pages = {2478-2484},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018i-TogCatTelAntCorFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018i-TogCatTelAntCorFra.mp4},
	author = {Marco Tognon and Elisabetta Cataldi and Hermes Tello Chavez and Gianluca Antonelli and Juan Cort{\'e}s and Antonio Franchi}
}
@article {2018d-FraCarBicRyl,
	title = {Full-Pose Tracking Control for Aerial Robotic Systems with Laterally-Bounded Input Force},
	journal = {IEEE Trans. on Robotics},
	volume = {34},
	year = {2018},
	month = {04/2018},
	pages = {534-541},
	abstract = {A class of abstract aerial robotic systems is introduced, the Laterally Bounded Force (LBF) vehicles, in which most of the control authority is expressed along a principal thrust direction, while in the lateral directions a (smaller and possibly null) force may be exploited to achieve full-pose tracking. This class approximates platforms endowed with non-collinear rotors that can modify the orientation of the total thrust in body frame. The proposed SE(3)-based control strategy achieves, if made possible by the force constraints, the independent tracking of position-plus-orientation trajectories. The method, which is proven using a Lyapunov technique, deals seamlessly with both under- and fully-actuated platforms, and guarantees at least the position tracking in the case of an unfeasible full-pose reference trajectory. Several experimental tests are presented, that clearly shown the approach practicability and the sharp improvement with respect to state of-the-art.},
	doi = {10.1109/TRO.2017.2786734},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018d-FraCarBicRyl.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018d-FraCarBicRyl-1.mp4 , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018d-FraCarBicRyl-2.mp4 , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018d-FraCarBicRyl-3.mp4},
	author = {Antonio Franchi and Ruggero Carli and Davide Bicego and Markus Ryll}
}
@conference {2017e-RylMusPieCatAntCacFra,
	title = {6D Physical Interaction with a Fully Actuated Aerial Robot},
	booktitle = {2017 IEEE Int. Conf. on Robotics and Automation},
	year = {2017},
	month = {05/2017},
	pages = {5190-5195},
	address = {Singapore},
	abstract = {This paper presents the design, control, and experimental validation of a novel fully{\textendash}actuated aerial robot for physically interactive tasks, named Tilt-Hex. We show how the Tilt-Hex, a tilted-propeller hexarotor is able to control the full pose (position and orientation independently) using a geometric control, and to exert a full-wrench (force and torque independently) with a rigidly attached end-effector using an admittance control paradigm. An outer loop control governs the desired admittance behavior and an inner loop based on geometric control ensures pose tracking. The interaction forces are estimated by a momentum based observer. Control and observation are made possible by a precise control and measurement of the speed of each propeller. An extensive experimental campaign shows that the Tilt-Hex is able to outperform the classical underactuated multi-rotors in terms of stability, accuracy and dexterity and represent one of the best choice at date for tasks requiring aerial physical interaction.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2017e-RylMusPieCatAntCacFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2017e-RylMusPieCatAntCacFra.mp4},
	author = {Markus Ryll and Giuseppe Muscio and Francesco Pierri and Elisabetta Cataldi and Gianluca Antonelli and Fabrizio Caccavale and Antonio Franchi}
}
@conference {2017m-SolFurCorFra,
	title = {Multi-Robot Path Planning with Maintenance of Generalized Connectivity},
	booktitle = {The 1st Int. Symp. on Multi-Robot and Multi-Agent Systems},
	year = {2017},
	month = {12/2017},
	address = {Los Angeles, CA},
	abstract = { This paper addresses the problem of generating a path for a fleet of robots navigating in a cluttered environment, while maintaining the so called generalized connectivity. The main challenge in the management of a group of robots is to ensure the coordination between them, taking into account limitations in communication range and sensors, possible obstacles, inter-robot avoidance and other constraints. The Generalized Connectivity Maintenance (GCM) theory already provides a way to represent and consider the aforementioned constraints, but previous works only find solutions via locally-steering functions that do not provide global and optimal solutions. In this work, we merge the GCM theory with randomized path- planning approaches, and local path optimization techniques to derive a tool that can provide global, good-quality paths. The proposed approach has been intensively tested and verified by mean of numerical simulations.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2017m-SolFurCorFra-preprint.pdf},
	author = {Yoann Solana and Michele Furci and Juan Cort{\'e}s and Antonio Franchi}
}
@conference {2017i-MicCenZacFra,
	title = {Nonlinear Control of Multi-Rotor Aerial Vehicles Based on the Zero-Moment Direction},
	booktitle = {20th IFAC World Congress},
	year = {2017},
	month = {07/2017},
	address = {Toulouse, France},
	abstract = {A quaternion-based nonlinear control strategy is here presented to steer and keep a generic multi-rotor platform in a given reference position. Exploiting a state feedback structure, the proposed solution ensures the stabilization of the aerial vehicle so that its linear and angular velocity are zero and its attitude is constant. The main feature of the designed controller is the identification of a zero-moment direction in the feasible force space, i.e., a direction along which the control force intensity can be assigned independently of the control moment. The asymptotic convergence of the error dynamics is confirmed by simulation results on a hexarotor with tilted propellers.
},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2017i-MicCenZacFra-preprint.pdf},
	author = {Giulia Michieletto and Angelo Cenedese and Luca Zaccarian and Antonio Franchi}
}
@conference {2017h-SanAreTogCamFra,
	title = {Visual Marker based Multi-Sensor Fusion State Estimation},
	booktitle = {20th IFAC World Congress},
	year = {2017},
	month = {07/2017},
	address = {Toulouse, France},
	abstract = {This paper presents the description and experimental results of a versatile Visual Marker based Multi-Sensor Fusion State Estimation that allows to combine a variable optional number of sensors and positioning algorithms in a loosely-coupling fashion, incorporating visual markers to increase its performances. This technique allows an aerial robot to navigate in different environments and carrying out different missions with the same state estimation architecture, exploiting the best from every sensor. The state estimation algorithm has been successfully tested controlling a quadrotor equipped with an extra IMU and a RGB camera used only to detect visual markers. The entire framework runs on an onboard computer, including the controllers and the proposed state estimator. The whole software is made publicly available to the scientific community through an open source implementation.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2017h-SanAreTogCamFra-preprint.pdf},
	author = {Jos{\'e}-Luis-L. Sanchez-Lopez and Victor Arellano-Quintana and Marco Tognon and Pascual Campoy and Antonio Franchi}
}
@conference {2016o-MicCenFra,
	title = {Bearing Rigidity Theory in SE(3)},
	booktitle = {55th IEEE Conference on Decision and Control},
	year = {2016},
	month = {12/2016},
	pages = {5950-5955},
	address = {Las Vegas, NV},
	abstract = {Rigidity theory has recently emerged as an efficient tool in the control field of coordinated multi-agent systems, such as multi-robot formations and UAVs swarms, that are characterized by sensing, communication and movement capabilities. This work aims at describing the rigidity properties for frameworks embedded in the three-dimensional Special Euclidean space SE(3) wherein each agent has 6DoF. In such scenario, it is assumed that the devices are able to gather bearing measurements w.r.t. their neighbors, expressing them into their own body frame. The goal is then to identify the framework transformations that allow to preserve such measurements maintaining it rigid. Rigidity properties are mathematically formalized in this work which differs from the previous ones as it faces the extension in three-dimensional space dealing with the 3D rotations manifold. In particular, the attention is focused on the infinitesimal SE(3)-rigidity for which a necessary and sufficient condition is provided.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2016o-MicCenFra-preprint.pdf},
	author = {Giulia Michieletto and Angelo Cenedese and Antonio Franchi}
}
@article {2016h-SteCogOriBueFra,
	title = {Ground and Aerial Mutual Localization using Anonymous Relative-Bearing Measurements},
	journal = {IEEE Transaction on Robotics},
	volume = {32},
	year = {2016},
	month = {09/2017},
	pages = {1133-1151},
	abstract = {We present a  decentralized algorithm for estimating mutual poses (i.e., relative positions and orientations) in a group of mobile robots. The algorithm uses only anonymous relative-bearing measurements obtainable, e.g., using onboard monocular cameras, and onboard motion measurements, such as inertial ones (acceleration and angular velocity). 
Onboard relative-bearing sensors supply anonymous measurements, i.e., they  provide the directions along which other robots are located but each direction is not associated to any robot (identities are unknown).
The issue of anonymity is often overlooked in theory but represents a real problem in practice, especially when employing onboard vision.
The solution is first presented for ground robots, in SE(2), and then for aerial robots, in SE(3), in order to emphasize the difference between the two cases.
The proposed method is based on a two-step approach, the first uses instantaneous geometrical arguments on the anonymous measurements in order to retrieve the most likely unscaled relative configurations together with the identities, the second uses a numeric Bayesian filtering in order to take advantage of the motion model over time and to retrieve the scale.
The proposed method exhibits robustness w.r.t. false positives and negatives of the robot detector.
An extensive experimental validation of the algorithm is performed using Khepera III ground mobile robots and quadrotor aerial robots.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2016h-SteCogOriBueFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2016h-SteCogOriBueFra.mp4},
	author = {Paolo Stegagno and Marco Cognetti and Giuseppe Oriolo and Heinrich H. B{\"u}lthoff and Antonio Franchi}
}
@conference {2016d-CarTodCarFraSch,
	title = {Multi-Robot Localization via GPS and Relative Measurements in the Presence of Asynchronous and Lossy Communication},
	booktitle = {15th European Control Conference},
	year = {2016},
	month = {07/2016},
	address = {Aalborg, Denmark},
	author = {Andrea Carron and Marco Todescato and Ruggero Carli and Antonio Franchi and Luca Schenato}
}
@conference {2013k-AntCatRobChiFra,
	title = {Experimental Validation of a New Adaptive Control for Quadrotors},
	booktitle = {2013 IEEE/RSJ Int. Conf. on Intelligent Robots and Systems},
	year = {2013},
	month = {11/2013},
	address = {Tokyo, Japan},
	keywords = {UAV hardware platforms},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2013k-AntCatRobChiFra-preprint.pdf},
	author = {Gianluca Antonelli and Elisabetta Cataldi and Paolo Robuffo Giordano and Stefano Chiaverini and Antonio Franchi}
}
@article {2011q-SonFraChuKimBueRob,
	title = {Human-Centered Design and Evaluation of Haptic Cueing for Teleoperation of Multiple Mobile Robots},
	journal = {IEEE Transactions on Systems, Man, \& Cybernetics. Part B: Cybernetics},
	volume = {43},
	year = {2013},
	month = {04/2013},
	pages = {597-609},
	abstract = {In this paper, we investigate the effect of haptic cueing on human operator{\textquoteright}s performance in the field of bilateral teleoperation of multiple mobile robots, in particular multiple unmanned aerial vehicles (UAVs). Two aspects of human performance are deemed important in this area, namely the maneuverability of mobile robots and perceptual sensitivity of the remote environment. We introduce metrics that allow us to address these aspects in two psychophysical studies, which are reported here. Three fundamental haptic cue types were evaluated. The Force cue conveys information on the proximity of the commanded trajectory to obstacles in the remote environment. The Velocity cue represents the mismatch between the commanded and actual velocity of the UAVs and can implicitly provide a rich amount of information regarding the actual behavior of the UAVs. Finally, the Velocity+Force cue is a linear combination of the two.
Our experimental results show that while maneuverability is best supported by the Force cue feedback, perceptual sensitivity is best served by the Velocity cue feedback. In addition, we show that large gains in the haptic feedbacks do not always guarantee an enhancement in teleoperator{\textquoteright}s performance.},
	keywords = {Evaluation, Force feedback, Haptics, Multi-robot systems, Psychophysical evaluation of haptic feedback, Psychophysics, Teleoperation},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2013a-SonFraChuKimBueRob_1.pdf},
	author = {Hyoung Il Son and Antonio Franchi and Lewis L. Chuang and Junsuk Kim and Heinrich H. B{\"u}lthoff and Paolo Robuffo Giordano}
}
@article {2013i-CenFraMarOri,
	title = {Simultaneous Calibration of Odometry  and Sensor Parameters for Mobile Robots},
	journal = {IEEE Transaction on Robotics},
	volume = {29},
	year = {2013},
	month = {04/2013},
	pages = {475-492},
	abstract = {Consider a differential-drive mobile robot equipped with an on-board exteroceptive sensor that can estimate its own motion, e.g., a range-finder. Calibration of this robot involves estimating six parameters: three for the odometry (radii and distance between the wheels), and three for the pose of the sensor with respect to the robot. After analyzing the observability of this problem, this paper describes a method for calibrating all parameters at the same time, without the need for external sensors or devices, using only the measurement of the wheels velocities and the data from the exteroceptive sensor. The method does not require the robot to move along particular trajectories. Simultaneous calibration is formulated as a maximum-likelihood problem and the solution is found in a closed form. Experimental results show that the accuracy of the proposed calibration method is very close to the attainable limit given by the Cram{\`e}r{\textendash}Rao bound.},
	keywords = {Calibration, Calibration of ground robots, Estimation},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2013i-CenFraMarOri.pdf},
	author = {Andrea Censi and Antonio Franchi and Luca Marchionni and Giuseppe Oriolo}
}
@conference {2012c-CogSteFraOriBue,
	title = {3D Mutual Localization with Anonymous Bearing Measurements},
	booktitle = {2012 IEEE Int. Conf. on Robotics and Automation},
	year = {2012},
	month = {05/2012},
	address = {St. Paul, MN},
	abstract = {We present a decentralized algorithm for estimating mutual 3-D poses in a group of mobile robots, such as a team of UAVs. Our algorithm uses bearing measurements reconstructed, e.g., by a visual sensor, and inertial measurements coming from the robot IMU. Since identification of a specific robot in a group would require visual tagging and may be cumbersome in practice, we simply assume that the bear- ing measurements are anonymous. The proposed localization method is a non-trivial extension of our previous algorithm for the 2-D case, and exhibits similar performance and robustness. An experimental validation of the algorithm has been performed using quadrotor UAVs.},
	keywords = {Distributed algorithms, Estimation, Localization, Localization of aerial robots, Multi-robot systems},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2012c-CogSteFraOriBue.pdf},
	author = {Marco Cognetti and Paolo Stegagno and Antonio Franchi and Giuseppe Oriolo and Heinrich H. B{\"u}lthoff}
}
@conference {2012l-CogSteFraOri,
	title = {Two Measurement Scenarios for Anonymous Mutual Localization in Multi-UAV Systems},
	booktitle = {2nd IFAC Workshop on Multivehicle Systems},
	year = {2012},
	month = {10/2012},
	address = {Espoo, Finland},
	keywords = {Estimation, Localization, Localization of aerial robots, Multi-robot systems},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2012l-CogSteFraOri-preprint.pdf},
	author = {Marco Cognetti and Paolo Stegagno and Antonio Franchi and Giuseppe Oriolo}
}
@conference {2011d-SonKimChuFraRobLeeBue,
	title = {An Evaluation of Haptic Cues on the Tele-Operator{\textquoteright}s Perceptual  Awareness of Multiple UAVs{\textquoteright} Environments},
	booktitle = { IEEE  World Haptics Conference},
	year = {2011},
	month = {06/2011},
	pages = {149-154},
	address = {Istanbul, Turkey},
	abstract = {The use of multiple unmanned aerial vehicles (UAVs) is increasingly being incorporated into a wide range of teleoperation applications. To date, relevant research has largely been focused on the development of appropriate control schemes. In this paper, we extend previous research by investigating how control performance could be improved by providing the teleoperator with haptic feedback cues. First, we describe a control scheme that allows a teleoperator to manipulate the flight of multiple UAVs in a remote environment. Next, we present three designs of haptic cue feedback that could increase the teleoperator{\textquoteright}s environmental awareness of such a remote environment. These cues are based on the UAVs{\textquoteright} i) velocity information, ii) proximity to obstacles, and iii) a combination of these two sources of information. Finally, we present an experimental evaluation of these haptic cue designs. Our evaluation is based on the teleoperator{\textquoteright}s perceptual sensitivity to the physical environment inhabited by the multiple UAVs. We conclude that a teleoperator{\textquoteright}s perceptual sensitivity is best served by haptic feedback cues that are based on the velocity information of multiple UAVs.},
	keywords = {Evaluation, Force feedback, Haptics, Multi-robot systems, Psychophysics, Teleoperation},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2011d-SonKimChuFraRobLeeBue-preprint.pdf},
	author = {Hyoung Il Son and Junsuk Kim and Lewis L. Chuang and Antonio Franchi and Paolo Robuffo Giordano and Dongjun Lee and Heinrich H. B{\"u}lthoff}
}
@conference {2011h-SonChuFraKimLeeLeeBueRob,
	title = {Measuring an Operator{\textquoteright}s Maneuverability Performance in the Haptic Teleoperation of Multiple Robots},
	booktitle = {2011 IEEE/RSJ Int. Conf. on Intelligent Robots and Systems},
	year = {2011},
	month = {09/2011},
	pages = {3039-3046},
	address = {San Francisco, CA},
	abstract = {In this paper, we investigate the maneuverability performance of human teleoperators on multi-robots. First, we propose that maneuverability performance can be assessed by a frequency response function that jointly considers the input force of the operator and the position errors of the multi-robot system that is being maneuvered. Doing so allows us to evaluate maneuverability performance in terms of the human teleoperator{\textquoteright}s interaction with the controlled system. This allowed us to effectively determine the suitability of different haptic cue algorithms in improving teleoperation maneuverability. Performance metrics based on the human teleoperator{\textquoteright}s frequency response function indicate that maneuverability performance is best supported by a haptic feedback algorithm which is based on an obstacle avoidance force.},
	keywords = {Evaluation, Force feedback, Haptics, Multi-robot systems, Psychophysics, Teleoperation},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2011h-SonChuFraKimLeeLeeBueRob-preprint.pdf},
	author = {Hyoung Il Son and Lewis L. Chuang and Antonio Franchi and Junsuk Kim and Dongjun Lee and Seong-Whan Lee and Heinrich H. B{\"u}lthoff and Paolo Robuffo Giordano}
}
@conference {2011m-SteCogFraOri,
	title = {Mutual Localization using Anonymous Bearing Measurements},
	booktitle = {2011 IEEE/RSJ Int. Conf. on Intelligent Robots and Systems},
	year = {2011},
	month = {09/2011},
	pages = {469-474},
	address = {San Francisco, CA},
	abstract = {This paper addresses the problem of mutual localization in multi-robot systems in presence of anonymous (i.e., without the identity information) bearing-only measurements. The solution of this problem is relevant for the design and implementation of any decentralized multi-robot algorithm/control. A novel algorithm for probabilistic multiple registration of these measurements is presented, where no global localization, distances, or identity are used. With respect to more conventional solutions that could be conceived on the basis of the current literature, our method is theoretically suitable for tasks requiring frequent, many-to-many encounters among agents (e.g., formation control, cooperative exploration, multiple-view environment sensing). An extensive experimental study validates our method and compares it with the fullinformative case of bearing plus-distance measurements. The results show that the proposed localization system exhibits an accuracy commensurate to our previous method [1] which uses bearing-plus-distance information.},
	keywords = {Distributed algorithms, Estimation, Localization, Multi-robot systems},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2011m-SteCogFraOri-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2011m-SteCogFraOri.mp4},
	author = {Paolo Stegagno and Marco Cognetti and Antonio Franchi and Giuseppe Oriolo}
}
