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489documents trouvés

17138
26/07/2017

Design of a sensor-based controller performing u-turn to navigate in orchards

A.DURAND PETITEVILLE, E.LE FLECHER, V.CADENAT, T.SENTENAC, S.VOUGIOUKAS

Univ. of California, Davis, RAP

Manifestation avec acte : International Conference on Informatics in Control, Automation and Robotics ( ICINCO ) 2017 du 26 juillet au 28 juillet 2017, Madrid (Espagne), Juillet 2017, 10p. , N° 17138

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140095
17136
13/07/2017

Hyper-optimization tools comparison for parameter tuning applications

C.MAURICE, J.MADRIGAL DIAZ, F.LERASLE

RAP

Rapport LAAS N°17136, Juillet 2017, 6p.

Non disponible

140092
17113
28/06/2017

Toward a Correct-and-Scalable Verification of Concurrent Robotic Systems: Insights on Formalisms and Tools

M.FOUGHALI

RIS

Manifestation avec acte : International Conference on Application of Concurrency to System Design ( ACSD ) 2017 du 28 juin au 30 juin 2017, Zaragosse (Espagne), Juin 2017, 10p. , N° 17113

Lien : https://hal.archives-ouvertes.fr/hal-01515012

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Abstract

Formal verification of robotic functional components is extremely important. Indeed, with the growing involvement of autonomous systems in everyday life, we may no longer rely on classical testing and simulation to establish our trust in them. However, the formalization of such systems is challenging considering the various existing formalisms and their respective advantages/drawbacks. One may express more easily in one formalism and verify more easily in another depending on the aspects/properties they are modeling/verifying. Furthermore, both the reusability of the formalization and the scalability of the obtained formal models are crucial elements in the verification process. In this paper, we present modeling concurrency aspects of robotic functional components in Time Petri Nets, Timed Automata and Timed Automata extended with urgencies. Formal models are automatically generated and verification is conducted on each of them. Both the expressiveness of the formalisms and scalability of the obtained models are evaluated and future directions are consequently outlined.

140054
17133
27/06/2017

Robustness to inertial parameter errors for legged robots balancing on level ground

N.GIFTSUN, A.DEL PRETE, F.LAMIRAUX

GEPETTO

Rapport LAAS N°17133, Juin 2017, 8p.

Lien : https://hal.archives-ouvertes.fr/hal-01533136

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Abstract

Model-based control has become more and more popular in the legged robots community in the last ten years. The key idea is to exploit a model of the system to compute precise motor commands that result in the desired motion. This allows to improve the quality of the motion tracking, while using lower gains, leading so to higher compliance. However, the main flaw of this approach is typically its lack of robustness to modeling errors. In this paper we focus on the robustness of inverse-dynamics control to errors in the inertial parameters of the robot. We assume these parameters to be known, but only with a certain accuracy. We then propose a computationally-efficient optimization-based controller that ensures the balance of the robot despite these uncertainties. We used the proposed controller in simulation to perform different reaching tasks with the HRP-2 humanoid robot, in the presence of various modeling errors. Comparisons against a standard inverse-dynamics controller through hundreds of simulations show the superiority of the proposed controller in ensuring the robot balance.

139953
16256
31/05/2017

Manipulation planning: building paths on constrained manifolds

J.MIRABEL, F.LAMIRAUX

GEPETTO

Manifestation avec acte : IEEE International Conference on Robotics and Automation ( ICRA ) 2017 du 29 mai au 03 juin 2017, Singapour (Singapour), Mai 2017, 16p. , N° 16256

Lien : https://hal.archives-ouvertes.fr/hal-01360409

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Abstract

Constrained motion planning and Manipulation planning, for generic non-linear constraints, highly rely on the ability of solving non-linear equations. The Newton-Raphson method is often used in this context. This work tackles the problem of continuity that arises when projecting paths point wise with such method. A theoretical proof of an interval of continuity for the Newton-Raphson iteration function is given. This interval requires to bound from above the norm of the Hessian of the constraints. A method to compute this bound for constraints involving joint positions and orientations is proposed. Then, this theoretical result is used in two path projection algorithm to give a certicate of continuity of the continuously projected path. Finally, simulations are run on several problems.

139882
17046
31/05/2017

Adaptive closed-loop speed control of BLDC motors with applications to multi-rotor aerial vehicles

A.FRANCHI, A.MALLET

RIS, IDEA

Manifestation avec acte : IEEE International Conference on Robotics and Automation ( ICRA ) 2017 du 29 mai au 03 juin 2017, Singapour (Singapour), Mai 2017, 6p. , N° 17046

Lien : https://hal.laas.fr/hal-01476812

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Abstract

This paper introduces the adaptive bias and adaptive gain (ABAG) algorithm for closed-loop electronic speed control (ESC) of the brushless direct current (BLDC) motors typically used to spin the propellers in multi-rotor aerial robots. The ABAG algorithm is adaptive and robust in the sense that it does not require the knowledge of any mechanical/electrical parameter of the motor/propeller group and that neither a pre-calibration nor the knowledge of the feedforward/nominal input is needed. The ABAG algorithm is amenable to an extremely low complexity implementation. We experimentally prove that it can run in 27.5 µs on a 8 MHz microcontroller with no floating point unit and limited arithmetic capabilities allowing only 8-bit additions, subtractions and multiplications. Besides the controller implementation we present a self-contained open source software architecture that handles the entire speed control process, including clock synchronization, and over-current and blockage safeties. The excellent performance and robustness of ABAG are shown by experimental tests and aerial physical interaction experiments.

139881
17038
29/05/2017

Control of statically hoverable multi-rotor aerial vehicles and application to rotor-failure robustness for hexarotors

G.MICHIELETTO, M.RYLL, A.FRANCHI

RIS

Manifestation avec acte : IEEE International Conference on Robotics and Automation ( ICRA ) 2017 du 29 mai au 03 juin 2017, Singapour (Singapour), Mai 2017, 6p. , N° 17038

Lien : https://hal.laas.fr/hal-01476816

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Abstract

Standard hexarotors are often mistakenly considered 'by definition' fail-safe multi-rotor platforms because of the two additional propellers when compared to quadrotors. However this is not true, in fact, a standard hexarotor cannot statically hover with 'only' five propellers. In this paper we provide a set of new general algebraic conditions to ensure static hover for any multi-rotor platform with any number of generically oriented rotors. These are elegantly formulated as the full-rankness of the control moment input matrix, and the non-orthogonality between its null-space and the row space of the control force input matrix. Input saturations and safety margins are also taken into account with an additional condition on the null-space of control moment input matrix. A deep analysis on the hoverability properties is then carried out focusing on the propeller loss in a hexarotor platform. Leveraging our general results we explain why a standard hexarotor is not robust and how it can be made robust thanks to a particular tilt of the rotors. We finally propose a novel cascaded controller based on a preferential direction in the null-space of the control moment input matrix for the large class of statically hoverable multi-rotors, which goes far beyond standard platforms, and we apply this controller to the case of failed tilted hexarotor.

139273
16250
29/05/2017

Manipulation planning: addressing the crossed foliation issue

J.MIRABEL, F.LAMIRAUX

GEPETTO

Manifestation avec acte : IEEE International Conference on Robotics and Automation ( ICRA ) 2017 du 29 mai au 03 juin 2017, Singapour (Singapour), Mai 2017, 6p. , N° 16250

Lien : https://hal.archives-ouvertes.fr/hal-01358767

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Abstract

This paper deals with manipulation planning. First, we propose a new tool called the constraint graph to describe the various motion constraints relative to a manipulation planning problem. Then, we describe a problem arising for some manipulation planning problems called the crossed foliation issue. We propose a extension of RRT algorithm that explores the leaves of the foliations generated by motion constraints and that solves the crossed foliation problem. Finally, we show a wide variety of problem that our approach can solve.

139880
17036
29/05/2017

6D physical interaction with a fully actuated aerial robot

M.RYLL, G.MUSCIO, F.PIERRI, E.CATALDI, G.ANTONELLI, F.CACCAVALE, A.FRANCHI

RIS, University of Basilicata, UNICAS

Manifestation avec acte : IEEE International Conference on Robotics and Automation ( ICRA ) 2017 du 29 mai au 03 juin 2017, Singapour (Singapour), Mai 2017, 6p. , N° 17036

Lien : https://hal.laas.fr/hal-01476814

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Abstract

This paper presents the design, control, and experimental validation of a novel fully–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 represents one of the best choice at date for tasks requiring aerial physical interaction.

139259
17039
29/05/2017

Dynamic decentralized control for protocentric aerial manipulators

M.TOGNON, B.YUKSEL, G.BUONDONNO, A.FRANCHI

RIS, MPI, Rome

Manifestation avec acte : IEEE International Conference on Robotics and Automation ( ICRA ) 2017 du 29 mai au 03 juin 2017, Singapour (Singapour), Mai 2017, 6p. , N° 17039

Lien : https://hal.laas.fr/hal-01476817

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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.

139275
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