@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}
}
@article {2021f-HamUsaSabStaTogFra,
	title = {Design of Multirotor Aerial Vehicles: a Taxonomy Based on Input Allocation},
	journal = {The International Journal of Robotics Research},
	volume = {40},
	year = {2021},
	pages = {1015-1044},
	doi = {10.1177/02783649211025998},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2021f-HamUsaSabStaTogFra.pdf},
	author = {Mahmoud Hamandi and Federico Usai and Quentin Sabl{\'e} and Nicolas Staub and Marco Tognon and Antonio Franchi}
}
@article {2021g-OllTogSuaLeeFra,
	title = {Past, Present, and Future of Aerial Robotic Manipulators},
	journal = {IEEE Transactions on Robotics},
	year = {2021},
	doi = {10.1109/TRO.2021.3084395},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2021g-OllTogSuaLeeFra.pdf},
	author = {Anibal Ollero and Marco Tognon and Alejandro Suarez and Dongjun Lee and Antonio Franchi}
}
@conference {2021l-HamSabTogFra,
	title = {Understanding the Omnidirectional Capability of a Generic Multi-rotor Aerial Vehicle},
	booktitle = {2021 Aerial Robotic Systems Physically Interacting with the Environment (AIRPHARO)},
	year = {2021},
	month = {Oct.},
	address = {Biograd na Moru, Croatia},
	author = {Mahmoud Hamandi and Quentin Sabl{\'e} and Marco Tognon and Antonio Franchi}
}
@conference {2020k-UmiTogSanOriFra,
	title = {Communication-based and Communication-less approaches for Robust Cooperative Planning in Construction with a Team of UAVs},
	booktitle = {2020 Int. Conf. on Unmanned Aircraft Systems},
	year = {2020},
	month = {07/2020},
	address = {Athens, Greece},
	abstract = {In this paper, we analyze the coordination problem of groups of aerial robots for assembly applications. With the enhancement of aerial physical interaction, construction applications are becoming more and more popular. In this domain, the multi-robot solution is very interesting to reduce the execution time. However, new methods to coordinate teams of aerial robots for the construction of complex structures are required. In this work, we propose an assembly planner that considers both assembly and geometric constraints imposed by the particular desired structure and employed robots, respectively. An efficient graph representation of the task dependencies is employed. Based on this framework, we design two assembly planning algorithms that are robust to robot failures. The first is centralized and communication-based. The second is distributed and communication-less. The latter is a solution for scenarios in which the communication network is not reliable. Both methods are validated by numerical simulations based on the assembly scenario of Challenge 2 of the robotic competition MBZIRC2020.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020k-UmiTogSanOriFra.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020k-UmiTogSanOriFra.mp4},
	author = {Elena Umili and Marco Tognon and Dario Sanalitro and Giuseppe Oriolo and Antonio Franchi}
}
@conference {2020d-HamTogFra,
	title = {Direct Acceleration Feedback Control of Quadrotor Aerial Vehicles},
	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/2020d-HamTogFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020d-HamTogFra.mp4},
	author = {Mahmoud Hamandi and Marco Tognon and Antonio Franchi}
}
@article {2020a-NavSabTogPucFra,
	title = {Direct Force Feedback Control and Online Multi-task Optimization for Aerial Manipulators},
	journal = {IEEE Robotics and Automation Letters},
	volume = {5},
	year = {2020},
	month = {04/2020},
	pages = {331-338},
	abstract = {In this paper, we present an optimization-based method for controlling aerial manipulators in physical contact with the environment. The multi-task control problem, which includes hybrid force-motion tasks, energetic tasks, and position/postural tasks, is recast as a quadratic programming problem with equality and inequality constraints, which is solved online. Thanks to this method, the aerial platform can be exploited at its best to perform the multi-objective tasks, with tunable priorities, while hard constraints such as contact maintenance, friction cones, joint limits, maximum and minimum propeller speeds are all respected. An on-board force/torque sensor mounted at the end effector is used in the feedback loop in order to cope with model inaccuracies and reject external disturbances. Real experiments with a multi-rotor platform and a multi-DoF lightweight manipulator demonstrate the applicability and effectiveness of the proposed approach in the real world.},
	keywords = {Aerial Physical Interaction, Aerial Robotics},
	doi = {10.1109/LRA.2019.2958473},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020a-NavSabTogPucFra.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020a-NavSabTogPucFra.mp4},
	author = {Gabriele Nava and Quentin Sabl{\'e} and Marco Tognon and Daniele Pucci and Antonio Franchi}
}
@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}
}
@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}
}
@conference {2020j-HamSawTogFra,
	title = {Omni-Plus-Seven (O7+): An Omnidirectional Aerial Prototype with a Minimal Number of Uni-directional Thrusters},
	booktitle = {2020 Int. Conf. on Unmanned Aircraft Systems},
	year = {2020},
	month = {07/2020},
	address = {Athens, Greece},
	abstract = {The aim of this paper is to present the design of a novel omnidirectional Unmanned Aerial Vehicle (UAV) with seven uni-directional thrusters, called O+7. The paper formally defines the O+ design for a generic number of propellers and presents its necessary conditions; then it illustrates a method to optimize the placement and orientation of the platform{\textquoteright}s propellers to achieve a balanced O+ design. The paper then details the choice of the parameters of the O7+ UAV, and highlights the required mechanical and electrical components. The resultant platform is tested in simulation, before being implemented as a prototype. The prototype is firstly static-bench tested to match its nominal and physical models, followed by hovering tests in multiple orientations. The presented prototype shows the ability to fly horizontally, upside down and at a tilted angle.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020j-HamSawTogFra.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020j-HamSawTogFra.mp4},
	author = {Mahmoud Hamandi and Kapil Sawant and Marco Tognon and Antonio Franchi}
}
@book {2020g-TogFra,
	title = {Theory and Applications for Control of Aerial Robots in Physical Interaction Through Tethers},
	series = {Springer Tracts in Advanced Robotics},
	volume = {140},
	year = {2020},
	month = {07/2020},
	abstract = {This book focuses on the study of autonomous aerial robots interacting with the surrounding environment, and in particular on the design of new control and motion planning methods for such systems. Nowadays, autonomous aerial vehicles are extensively employed in many fields of application but mostly as autonomously moving sensors used only to sense the environment. On the other hand, in the recent field of aerial physical interaction, the goal is to go beyond sensing-only applications and to fully exploit aerial robots capabilities in order to interact with the environment, exchanging forces for pushing/pulling/sliding, and manipulating objects. However, due to the different nature of the problems, new control methods are needed. These methods have to preserve the system stability during the interaction and to be robust against external disturbances, finally enabling the robot to perform a given task. Moreover, researchers and engineers need to face other challenges generated by the high complexity of aerial manipulators, e.g., a large number of degrees of freedom, strong nonlinearities, and actuation limits. Furthermore, trajectories of the aerial robots have to be carefully computed using motion planning techniques. To perform the sough task in a safe way, the planned trajectory must avoid obstacles and has to be suitable for the dynamics of the system and its actuation limits. With the aim of achieving the previously mentioned general goals, this book considers the analysis of a particular class of aerial robots interacting with the environment: tethered aerial vehicles. The study of particular systems, still encapsulating all the challenges of the general problem, helps on acquiring the knowledge and the expertise for a subsequent development of more general methods applicable to aerial physical interaction. This work focuses on the thorough formal analysis of tethered aerial vehicles ranging from control and state estimation to motion planning. In particular, the differential flatness property of the system is investigated, finding two possible sets of flat outputs that reveal new capabilities of such a system. One contains the position of the vehicle and the link internal force (equivalently the interaction force with the environment), while the second contains the position and a variable linked to the attitude of the vehicle. This shows new control and physical interaction capabilities different from standard aerial robots in contact-free flight. In particular, the first set of flat outputs allows realizing one of the first {\textquotedblleft}free-floating{\textquotedblright} versions of the classical hybrid force-motion control for standard grounded manipulators. Based on these results we designed two types of controllers. The first is an easy-to-implement controller based on a hierarchical approach. Although it shows good performance in quasi-static conditions, actually the tracking error increases when tracking a dynamic trajectory. Thus, a second controller more suited for tracking problems has been designed based on the dynamic feedback linearization technique. Two observers, for the 3D and 2D environments, respectively, have been designed in order to close the control loop using a minimal sensorial setup. We showed that the tether makes possible to retrieve an estimation of the full state from only an IMU plus three encoders for the 3D case, while from just an IMU for the 2D case. Parts of those results were extended to a novel and original multi-robots case as well. We considered a multi-tethered system composed of two aerial robots linked to the ground and to each other by two links. The theoretical results on generic tethered aerial vehicles were finally employed to solve the practical and challenging problem of landing and takeoff on/from a sloped surface, enhancing the robustness and reliability of the maneuvers with respect to the contact-free flight solution.},
	isbn = {978-3-030-48659-4},
	doi = {10.1007/978-3-030-48659-4},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2020g-TogFra-preprint.pdf},
	author = {Marco Tognon 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}
}
@article {2019l-GabTogPalFra,
	title = {A Study on Force-based Collaboration in Swarms},
	journal = {Swarm Intelligence},
	volume = {14},
	year = {2019},
	month = {11/2019},
	pages = {57-82},
	abstract = {Cooperative manipulation is a basic skill in groups of humans, ani- mals, and in many robotic applications. Besides being an interesting challenge, communication-less approaches have been applied to groups of robots in order to achieve higher scalability and simpler hardware and software design. We present a generic model and control law for robots cooperatively manipulating an object, for both ground and floating systems.
The control method exploits a leader-follower scheme and is based only on implicit communication (i.e., the sensing of contact forces). The control objective mainly consists of steering the object manipulated by the swarm of robots to a desired position and orientation in a cooperative way. For a system with just one leader, we present analytical results on the equilibrium configurations and their stability that are then validated by numerical simulations. The role of object in- ternal forces (induced by the robots through contact forces) is discussed in terms of convergence of the object position and orientation to the desired values. We also present a discussion on additional properties of the controlled system that were investigated using thorough numerical analysis, namely, the robustness of the system when the object is subject to external disturbances in non-ideal condi- tions, and how the number of leaders in the swarm can affect the aforementioned convergence and robustness.},
	doi = {10.1007/s11721-019-00178-7},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2019l-GabTogPalFra.pdf},
	author = {Chiara Gabellieri and Marco Tognon and Dario Sanalitro and Lucia Pallottino 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 {2018h-TogGabPalFra,
	title = {Aerial Co-Manipulation with Cables: The Role of Internal Force for Equilibria, Stability, and Passivity},
	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 = {2577-2583},
	abstract = {This paper considers the cooperative manipulation of a cable-suspended load with two generic aerial robots without the need of explicit communication. The role of the internal force for the asymptotic stability of the beam position-and- attitude equilibria is analyzed in depth. Using a nonlinear Lyapunov-based approach, we prove that if a non-zero internal force is chosen, then the asymptotic stabilization of any desired beam attitude can be achieved with a decentralized and communication-less master-slave admittance controller. If, conversely, a zero internal force is chosen, as done in the majority of the state-of-the-art algorithms, the attitude of the beam is not controllable without communication. Furthermore, we formally prove the output-strictly passivity of the system with respect to an energy-like storage function and a certain input-output pair. This proves the stability and the robustness of the method during motion and in non-ideal conditions. The theoretical findings are validated through extensive simulations.},
	doi = {10.1109/LRA.2018.2803811},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018h-TogGabPalFra-preprint.pdf},
	author = {Marco Tognon and Chiara Gabellieri and Lucia Pallottino and Antonio Franchi}
}
@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 {2018e-TogFra,
	title = {Omnidirectional Aerial Vehicles with Unidirectional Thrusters: Theory, Optimal Design, and Control},
	journal = {IEEE Robotics and Automation Letters},
	volume = {3},
	year = {2018},
	month = {02/2018},
	pages = {2277-2282},
	abstract = {This letter presents a theoretical study on omnidirectional aerial vehicles with body-frame fixed unidirectional thrusters. Omniplus multirotor designs are defined as the ones that allow to exert a total wrench in any direction using positive-only lift force and drag moment (i.e., positive rotational speed) for each rotor blade. Algebraic conditions for a design to be omniplus are derived, a simple necessary condition being the fact that at least seven propellers have to be used. An energy optimal design strategy is then defined as the one minimizing the maximum norm of the input set needed to span a certain wrench ellipsoid for the adopted input allocation strategy. Two corresponding major design criteria are then introduced: first, a minimum allocation-matrix condition number aims at an equal sharing of the effort needed to generate wrenches in any direction; second, imposing a balanced design guarantees an equal sharing of the extra effort needed to keep the input in the nonnegative orthant. We propose a numerical algorithm to solve such optimal design problem and a control algorithm to control any omnidirectional platform. The work is concluded with informative simulation results in nonideal conditions.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018e-TogFra-preprint.pdf},
	author = {Marco Tognon and Antonio Franchi}
}
@conference {2018p-GabTogPalFra,
	title = {A Study on Force-based Collaboration in Flying Swarms},
	booktitle = {11th Int. Conf. on Swarm Intelligence ANTS 2018},
	year = {2018},
	month = {10/2018},
	address = {Rome, Italy},
	abstract = {This work investigates collaborative aerial transportation by swarms of agents based only on implicit information, enabled by the physical interaction among the agents and the environment. Such a coordinating mechanism in collaborative transportation is a basic skill in groups of social animals. We consider cable-suspended objects transported by a swarm of flying robots and we formu- late several hypothesis on the behavior of the overall system which are validated thorough numerical study. In particular, we show that a nonzero internal force re- duces to one the number of asymptotically stable equilibria and that the internal force intensity is directly connected to the convergence rate. As such, the internal force represents the cornerstone of a communication-less cooperative manipula- tion paradigm in swarms of flying robots. We also show how a swarm can achieve a stable transportation despite the imprecise knowledge of the system parameters.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018p-GabTogPalFra-preprint.pdf},
	author = {Chiara Gabellieri and Marco Tognon and Lucia Palottino and Antonio Franchi}
}
@conference {2017g-TogYueBuoFra,
	title = {Dynamic Decentralized Control for Protocentric Aerial Manipulators},
	booktitle = {2017 IEEE Int. Conf. on Robotics and Automation},
	year = {2017},
	month = {05/2017},
	pages = {6375-6380},
	address = {Singapore},
	abstract = {We present a control methodology for underactuated aerial manipulators that is both easy to implement on real systems and able to achieve highly dynamic behaviors. The method is composed by two parts: i) a nominal input/state trajectory generator that takes into account the full-body dynamics of the system exploiting its differential flatness property; ii) a decentralized feedback controller acting on the actuated degrees of freedom that confers the needed robustness to the closed-loop system. We demonstrate that the proposed controller is able to precisely track dynamic trajectories when implemented on a standard hardware. Comparative experiments clearly show the benefit of using the nominal input/state generator.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2017g-TogYueBuoFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2017g-TogYueBuoFra.mp4},
	author = {Marco Tognon and Burak Y{\"u}ksel and Gabriele Buondonno and Antonio Franchi}
}
@article {2017a-TogFra,
	title = {Dynamics, Control, and Estimation for Aerial Robots Tethered by Cables or Bars},
	journal = {IEEE Transaction on Robotics},
	volume = {33},
	year = {2017},
	month = {08/2017},
	pages = {834-845},
	keywords = {submitted},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/1603.07567-v2.pdf},
	author = {Marco Tognon and Antonio Franchi}
}
@conference {2017o-TogFra,
	title = {Landing and take-off on/from sloped and non-planar surfaces with more than 50 degrees of inclination},
	booktitle = {2017 International Micro Air Vehicle Conference},
	year = {2017},
	month = {09/2017},
	pages = {97-102},
	address = {Toulouse, France},
	abstract = {This technical paper summarizes the recent experimental results concerning the challenging problem of landing and take-off on/from a sloped surface with an aerial vehicle exploiting the force provided by an anchored taut tether. A special regard is given to the practical aspects concern- ing the experimental part. In this manuscript we show extreme landing and take-off maneuvers on slopes with at least 50{\textopenbullet} inclination and non flat surfaces, such as, e.g., on industrial pipes.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2017o-TogFra-preprint.pdf},
	author = {Marco Tognon and Antonio Franchi}
}
@conference {2016l-TogFra,
	title = {Position Tracking Control for an Aerial Robot Passively Tethered to an Independently Moving Platform},
	booktitle = {20th IFAC World Congress},
	year = {2017},
	month = {07/2017},
	address = {Toulouse, France},
	abstract = {We study the control problem of an aerial vehicle moving in the 3D space and connected to an independently moving platform through a physical link (e.g., a cable, a chain or a rope). The link is attached to the moving platform by means of a passive winch. The latter differs from an active winch by producing only a constant uncontrollable torque. We solve the problem of exact tracking of the 3D position of the aerial vehicle, either absolute or with respect to the moving platform, while the platform is independently moving. We prove two intrinsic properties of the system, namely, the dynamic feedback linearizability and the differential flatness with respect to the output of interest. Exploiting this properties we design a nonlinear controller able to exponentially steer the position of the aerial robot along any sufficiently smooth time-varying trajectory. The proposed method is tested through numerical simulations in several non-ideal cases.},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2016l-TogFra-preprint.pdf},
	author = {Marco Tognon 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}
}
@article {2016c-TogDasFra,
	title = {Observer-based Control of Position and Tension  for an Aerial Robot Tethered to a Moving Platform},
	journal = {IEEE Robotics and Automation Letters},
	volume = {1},
	year = {2016},
	note = {Also selected for presentation at the 2016 IEEE Int. Conf. on Robotics and Automation, Stockholm , Sweden},
	month = {01/2016},
	pages = {732-737},
	abstract = {In this paper we address a challenging version of the problem of controlling tethered aerial vehicles (also known as UAV, MAV, and UAS) by considering the aerial robot linked to a generic and independently moving platform. We solve the exact tracking control problem for both the 3D position of the robot (either absolute or with respect to the platform) and the tension along the link. To achieve this goal we prove some fundamental system properties, useful to design a nonlinear controller, such as differential flatness and dynamic feedback linearizability. To close the control loop a set of minimal and standard sensors is proposed. Then we show that it is possible to retrieve the full system state from those sensors by means of nonlinear measurements transformations and a bank of low-dimension estimators based on the nonlinear high gain observer. The ability of the proposed observer-controller method is tested by extensive numerical simulations spanning many non-ideal conditions.},
	keywords = {Aerial Physical Interaction, Aerial Robotics},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2016c-TogDasFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2016c-TogDasFra..mp4},
	author = {Marco Tognon and Sanket S. Dash 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}
}
@conference {2015h-TogFra,
	title = {Control of Motion and Internal Stresses for a Chain of Two Underactuated Aerial Robots},
	booktitle = {14th European Control Conference},
	year = {2015},
	month = {07/2015},
	pages = {1620-1625},
	address = {Linz, Austria},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2015h-TogFra-preprint.pdf},
	author = {Marco Tognon and Antonio Franchi}
}
@conference {2015j-TogFra,
	title = {Nonlinear Observer for the Control of Bi-Tethered Multi Aerial Robots},
	booktitle = {2015 IEEE/RSJ Int. Conf. on Intelligent Robots and Systems},
	year = {2015},
	month = {09/2015},
	pages = {1852-1857},
	address = {Hamburg, Germany},
	abstract = {We consider the problem of state-observation and control for a bi-tethered aerial system composed by a physical chain of two underactuated aerial robots, also called UAVs.  The controlled outputs are the Cartesian position of the last robot and the internal forces along the links. We aim at a minimal use of sensors in order to retrieve the full state. For this goal we propose an output transformation method whose applicability implies the system observability.  When this is the case we prove that it is possible to design a nonlinear state estimator based on the  high gain- and Luenberger-  observers that is able to retrieve the state from any dynamic condition. We also demonstrate how this estimator can be employed with a nonlinear controller for the Cartesian position and the link stresses while ensuring the stability in  closed-loop. We show the validity of the method for sensorial configurations composed only by two accelerometers (no gyros) and just two encoders, or two accelerometers (no gyros) and just two inclinometers. A realistic simulative validation concludes the paper.},
	keywords = {Aerial Physical Interaction, Aerial Robotics},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2015j-TogFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2015j-TogFra.mp4},
	author = {Marco Tognon and Antonio Franchi}
}
@conference {2015a-TogFra,
	title = {Nonlinear Observer-based Tracking Control of Link Stress and Elevation for a Tethered Aerial Robot using Inertial-only Measurements},
	booktitle = {2015 IEEE Int. Conf. on Robotics and Automation},
	year = {2015},
	month = {05/2015},
	pages = {3994-3999},
	address = {Seattle, WA},
	attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2015a-TogFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2015a-TogFra.mp4},
	author = {Marco Tognon and Antonio Franchi}
}
