@article {2022m-MohBicFraBarPra, title = {Aerial Tele-Manipulation with Passive Tool via Parallel Position/Force Control}, journal = {Applied Sciences, Special issue on Aerial Robotics for Inspection and Maintenance}, volume = {11}, year = {2021}, doi = {10.3390/app11198955}, author = {Mostafa Mohammadi and Davide Bicego and Antonio Franchi and Davide Barcelli and Domenico Prattichizzo} } @article {2021e-RylBicGiuLovFra, title = {FAST-Hex - A Morphing Hexarotor: Design, Mechanical Implementation, Control and Experimental Validation}, journal = {IEEE/ASME Transactions on Mechatronics}, year = {2021}, doi = {10.1109/TMECH.2021.3099197}, attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2021e-RylBicGiuLovFra.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2021e-RylBicGiuLovFra.mp4}, author = {Markus Ryll and Davide Bicego and Mattia Giurato and Marco Lovera 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} } @conference {2019f-SarKimBicTseOttFraKon, title = {Development of SAM: cable-Suspended Aerial Manipulator}, booktitle = {2019 IEEE Int. Conf. on Robotics and Automation}, year = {2019}, month = {05/2019}, address = {Montreal, Canada}, abstract = { High risk of a collision between rotor blades and the obstacles in a complex environment imposes restrictions on the aerial manipulators. To solve this issue, a novel system cable-Suspended Aerial Manipulator (SAM) is presented in this paper. Instead of attaching a robotic manipulator directly to an aerial carrier, it is mounted on an active platform which is suspended on the carrier by means of a cable. As a result, higher safety can be achieved because the aerial carrier can keep a distance from the obstacles. For self-stabilization, the SAM is equipped with two actuation systems: winches and propulsion units. This paper presents an overview of the SAM including the concept behind, hardware realization, control strategy, and the first experimental results.}, attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2019f-SarKimBicTseOttFraKon-preprint.pdf}, author = {Yuri Sarkisov and Min J. Kim and Davide Bicego and D. Tsetserukou and Christian Ott and Antonio Franchi and Konstantin Kondak} } @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} } @conference {2018o-FurBicFra, title = {Design and Input Allocation for Robots with Saturated Inputs via Genetic Algorithms}, booktitle = {12th IFAC Symposium on Robot Control}, year = {2018}, month = {08/2018}, address = {Budapest, Hungary}, abstract = {In this paper we consider fully-actuated and redundantly-actuated robots, whose saturated inputs can have high bandwidth or can be slowly varying (with dynamics). The slowly varying inputs can be considered as configurations for the system. The proposed strategy allows to find the optimal actuators{\textquoteright} configuration to optimize a cost function as the manipulability or the energy consumption. The approach allows for both a static design, which can include actuators{\textquoteright} parameters such as position, orientation, saturations, numbers of actuators, and for a dynamic design, where the configurations can be controlled by an input of the system. A generalized solution to the optimal problem is proposed with the use of genetic algorithms. The results are validated in two simulation scenarios: a reconfiguration of the actuators orientation of an redundantly-actuated planar robot for trajectory tracking and the design optimization of the orientation of the motors in a generalized hexa-rotor with arbitrary propeller orientation.}, attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018o-FurBicFra-preprint.pdf}, author = {Michele Furci and Davide Bicego and Antonio Franchi} } @conference {2018r-MorBicRylFra, title = {Energy-Efficient Trajectory Generation for a Hexarotor with Dual-Tilting Propellers}, booktitle = {2018 IEEE/RSJ Int. Conf. on Intelligent Robots and Systems}, year = {2018}, month = {10/2018}, address = {Madrid, Spain}, abstract = {In this paper, we consider a non-conventional hexarotor whose propellers can be simultaneously tilted about two orthogonal axes: in this way, its underactuation degree can be easily adapted to the task at hand. For a given tilt profile, the minimum-energy trajectory between two prescribed boundary states is explicitly determined by solving an optimal control problem with respect to the angular accelerations of the six brushless motors. We also perform, for the first time, a systematic study of the singularities of the control allocation matrix of the hexarotor, showing the presence of subtle singular configurations that should be carefully avoided in the design phase. Numerical experiments conducted with the FAST-Hex platform illustrate the theory and delineate the pros and cons of dual-tilting paradigm in terms of maneuverability and energy efficiency.}, attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018r-MorBicRylFra-preprint.pdf}, author = {Fabio Morbidi and Davide Bicego and Markus Ryll 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} } @article {2018u-StaMohBicDelYaPraRobLeeFra, title = {The Tele-MAGMaS: an Aerial-Ground Co-manipulator System}, journal = {IEEE Robotics and Automation Magazine}, volume = {25}, year = {2018}, month = {12/2018}, pages = {66-75}, attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018u-StaMohBicDelYaPraRobLeeFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018u-StaMohBicDelYaPraRobLeeFra.mp4}, author = {Nicolas Staub and Mostafa Mohammadi and Davide Bicego and Quentin Delamare and Hyunsoo Yang and Domenico Prattichizzo and Paolo Robuffo Giordano and Dongjun Lee and Antonio Franchi} } @conference {2018g-BicStaSabAreMisFra, title = {Towards a Flying Assistant Paradigm: the OTHex}, booktitle = {2018 IEEE Int. Conf. on Robotics and Automation}, year = {2018}, month = {05/2018}, pages = {6997-7002}, address = {Brisbane, Australia}, abstract = {This paper presents the OTHex platform for aerial manipulation developed at LAAS{\textendash}CNRS. The OTHex is probably the first multi-directional thrust platform designed to act as Flying Assistant which can aid human operators and/or Ground Manipulators to move long bars for assembly and maintenance tasks. The work emphasis is on task-driven custom design and experimental validations. The proposed control framework is built around a low-level geometric controller, and includes an external wrench estimator, an admittance filter, and a trajectory generator. This tool gives the system the necessary compliance to resist external force disturbances arising from contact with the surrounding environment or to parameter uncertainties in the load. A set of experiments validates the real-world applicability and robustness of the overall system.}, attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018g-BicStaSabAreMisFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018g-BicStaSabAreMisFra.mp4}, author = {Nicolas Staub and Davide Bicego and Quentin Sabl{\'e} and Victor Arellano-Quintana and Subodh Mishra and Antonio Franchi} } @conference {2018n-RylBicFra, title = {A Truly Redundant Aerial Manipulator exploiting a Multi-directional Thrust Base}, booktitle = {12th IFAC Symposium on Robot Control}, year = {2018}, month = {08/2018}, address = {Budapest, Hungary}, abstract = {We present a novel aerial manipulator concept composed of a fully actuated hexarotor aerial vehicle and an n degree of freedom manipulator. Aiming at interaction tasks, we present a trajectory following control framework for the end-effector of the manipulator. The system is modeled in Euler-Lagrangian formalism and in Denavit-Hartenberg form. Benefiting from the redundancy of the system, we present several cost function strategies based on the projected gradient method to optimize the aerial manipulator behavior. The control framework is based on exact feedback linearization. In an advanced simulation section, we thoroughly present the robustness of the system and its limits in two typical configuration constituted by an 8 and a 10 degrees of freedom redundant aerial manipulator.}, attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018n-RylBicFra-preprint.pdf}, author = {Markus Ryll and Davide Bicego and Antonio Franchi} } @conference {2017d-StaMohBicPraFra, title = {Towards Robotic MAGMaS: Multiple Aerial-Ground Manipulator Systems}, booktitle = {2017 IEEE Int. Conf. on Robotics and Automation}, year = {2017}, month = {05/2017}, pages = {1307-1312}, address = {Singapore}, abstract = {In this paper we lay the foundation of the first heterogeneous multi-robot system of the Multiple Aerial-Ground Manipulator System (MAGMaS) type. A MAGMaS consists of a ground manipulator and a team of aerial robots equipped with a simple gripper manipulator the same object. The idea is to benefit from the advantages of both kinds of platforms, i.e., physical strength versus large workspace. The dynamic model of such robotic systems is derived, and R Ro its characteristic structure exhibited. Based on the dynamical i structure of the system a nonlinear control scheme, augmented with a disturbance observer is proposed to perform trajectory tracking tasks in presence of model inaccuracies and external disturbances. The system redundancy is exploited by solving an optimal force/torque allocation problem that takes into account the heterogeneous system constraints and maximizes the force manipulability ellipsoid. Simulation results validated the proposed control scheme for this novel heterogeneous robotic system. We finally present a prototypical mechanical design and preliminary experimental evaluation of a MAGMaS composed by a kuka LWR4 and quadrotor based aerial robot.}, attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2017d-StaMohBicPraFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2017d-StaMohBicPraFra.mp4}, author = {Nicolas Staub and Mostafa Mohammadi and Davide Bicego and Domenico Prattichizzo and Antonio Franchi} } @conference {2016j-RylBicFra, title = {Modeling and Control of FAST-Hex: a Fully-Actuated by Synchronized-Tilting Hexarotor}, booktitle = {2016 IEEE/RSJ Int. Conf. on Intelligent Robots and System}, year = {2016}, month = {10/2016}, pages = {1689-1694}, address = {Daejeon, South Korea}, abstract = {We present FAST-Hex, a novel UAV concept which is able to smoothly change its configuration from underactuated to fully actuated by using only one additional motor that tilts all propellers at the same time. FAST-Hex can adapt to the task at hand by finely tuning its configuration from the efficient (but underactuated) flight (typical of coplanar multi{\textendash} rotor platforms) to the full-pose-tracking (but less efficient) flight, which is attainable by non-coplanar multi-rotors. We also introduce a novel full-pose geometric controller for generic multi-rotors (not only the FAST-Hex) that outperforms classical inverse dynamics approaches. The controller receives as input any reference pose in R^3{\texttimes}SO(3) (3D position + 3D orientation). Exact tracking is achieved if the reference pose is feasible with respect to the propeller spinning rate saturations. In case of unfeasibility a new feasible desired trajectory is generated online giving priority to the positional part. The new controller is tested with the FAST-Hex but can be used for many other multi-rotor platforms: underactuated, slightly fully-actuated and completely fully-actuated.}, attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2016j-RylBicFra-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2016j-RylBicFra.mp4}, author = {Markus Ryll and Davide Bicego and Antonio Franchi} }