Retour au site du LAAS-CNRS

Laboratoire d’analyse et d’architecture des systèmes

Publications de l'équipe gepetto

Choisir la langue : FR | EN

361documents trouvés

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

Diffusable

Plus d'informations

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

Diffusable

Plus d'informations

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
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

Diffusable

Plus d'informations

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
17052
01/05/2017

Adaptive synthesis of dynamically feasible full-body movements for the humanoid robot HRP-2 by flexible combination of learned dynamic movement primitives

A.MUKOVSKIY, C.VASSALLO, M.NAVEAU, O.STASSE, P.SOUERES, M.GIESE

Tubingen, GEPETTO

Revue Scientifique : Robotics and Autonomous Systems, Vol.91, pp.270-283, Mai 2017 , N° 17052

Lien : https://hal.archives-ouvertes.fr/hal-01484935

Diffusable

Plus d'informations

Abstract

Skilled human full-body movements are often planned in a highly predictive manner. For example, during walking while reaching towards a goal object results in steps and body postures are adapted to the goal position already multiple steps before the goal contact. The realization of such highly predictive behaviors for humanoid robots is a challenge because standard approaches, such as optimal control, result in computation times that are prohibitive for the predictive control of complex coordinated full-body movements over multiple steps. We devised a new architecture that combines the online-planning of complex coordinated full-body movements, based on the flexible combination of learned dynamic movement primitives, with a Walking Pattern Generator (WPG), based on Model Predictive Control (MPC), which generates dynamically feasible locomotion of the humanoid robot HRP-2. A dynamic filter corrects the Zero Moment Point (ZMP) trajectories in order to guarantee the dynamic feasibility of the executed behavior taking into account the upper-body movements, at the same time ensuring an accurate approximation of the planned motion trajectories. We demonstrate the high flexibility of the chosen movement planning approach, and the accuracy and feasibility of the generated motion. In addition, we show that a na¨ıvena¨ıve approach, which generates adaptive motion by using machine learning methods by the interpolation between feasible training motion examples fails to guarantee the stability and dynamic feasibility of the generated behaviors.

139327
17069
03/04/2017

Differential dynamical programming to control a cable driven actuator for the humanoid robot Romeo

F.FORGET, K.GIRAUD ESCLASSE, R.GELIN, N.MANSARD, O.STASSE

GEPETTO, Aldebaran

Rapport LAAS N°17069, Avril 2017, 8p.

Lien : https://hal.archives-ouvertes.fr/hal-01494676

Diffusable

Plus d'informations

Abstract

Autonomous robots such as legged robots and mobile manipulators imply new challenges in the design and the control of their actuators. In particular, it is desirable that the actuators are back-drivable, efficient (low friction) and compact. In this paper, we report the complete implementation of an advanced actuator based on screw, nut and cable. This actuator has been chosen for the humanoid robot Romeo. A similar model of the actuator has been used to control the humanoid robot Valkyrie. We expose the design of this actuator and present its Lagrangian model. The actuator being flexible, we propose a two-layer optimal control solver based on Differential Dynamical Programming. The actuator design, model identification and control is validated on a full actuator mounted in a work bench. The results show that this type of actuation is very suitable for legged robots and is a good candidate to replace strain wave gears.

139418
17070
03/04/2017

Regulation of the distance between the center of mass and the minimum moment axis for stabilized locomotion in humans

F.BAILLY, B.PINET, P.SOUERES, B.WATIER

GEPETTO

Rapport LAAS N°17070, Avril 2017, 15p.

Lien : https://hal.laas.fr/hal-01494117

Diffusable

Plus d'informations

Abstract

This study aims at showing that, to ensure stability, humans tend to minimize the distance between their center of mass and the minimal moment axis of contact forces. This work is based on a theoretical reasoning in mechanics and on experiments in human walking movement. A destabilizing setup was built on which five different experiments were carried out by 15 volunteers. We computed the distance between the minimal moment axis of the contact forces and the center of mass of the participants. This distance significantly increased (p < 0.001, ranging from 55.1 mm to 150.9 mm) as subjects balance was perturbed through the five different conditions (walking on a destabilizing setup, increasing walking speed, grasping or not a fixed element). Furthermore, the analysis of each segment's position with regard to the studied axis shows that heaviest segments are kept close to it, while lightest segments are less constrained around it (p < 0.001, from 145.7 mm to 493.1 mm). This might reveal a strategy used to obtain a fine control of the center of mass distance from the axis and thus a good regulation of the variation of whole body angular momentum. Tracking this distance could be used for different purposes, such as fall detection, prosthesis studies and trajectory generation in humanoid robotics.

139419
17055
22/03/2017

TALOS: A new humanoid research platform targeted for industrial applications

O.STASSE, T.FLAYOLS, R.BUDHIRAJA, K.GIRAUD ESCLASSE, J.CARPENTIER, A.DEL PRETE, P.SOUERES, N.MANSARD, F.LAMIRAUX, J.P.LAUMOND, L.MARCHIONNI, H.TOME, F.FERRO

GEPETTO, Pal Robotics

Rapport LAAS N°17055, Mars 2017, 8p.

Lien : https://hal.archives-ouvertes.fr/hal-01485519

Diffusable

Plus d'informations

Abstract

The upcoming generation of humanoid robots will have to be equipped with state-of-the-art technical features along with high industrial quality, but they should also offer the prospect of effective physical human interaction. In this paper we introduce a new humanoid robot capable of interacting with a human environment and targeting a whole range of industrial applications. This robot is able to handle weights of 6 Kg with an outstretched arm, and has powerful motors to carry out movements unavailable in previous generations of humanoid robots. Its kinematics has been specially designed for screwing and drilling motions. In order to make interaction possible with human operators, this robot is equipped with torque sensors to measure joint effort and high resolution encoders to measure both motor and joint positions. The humanoid robotics field has reached a stage where robustness and repeatibility is the next watershed. We believe that, this robot has the potential to become a powerful tool for the research community to successfully navigate this turning point, as the humanoid robot HRP-2 was in its own time.

139336
17054
22/03/2017

A Kinodynamic steering-method for legged multi-contact locomotion

P.FERNBACH, S.TONNEAU, A.DEL PRETE, M.TAIX

GEPETTO

Rapport LAAS N°17054, Mars 2017, 7p.

Lien : https://hal.laas.fr/hal-01486933

Diffusable

Plus d'informations

Abstract

We present a novel method for synthesizing collision-free, dynamic locomotion behaviors for legged robots, including jumping, going down a very steep slope, or recovering from a push using the arms of the robot. The approach is automatic and generic: non-gaited motions, comprising arbitrary contact postures can be generated along any environment. At the core of our framework is a new steering method that generates trajectories connecting two states of the robot. These trajectories account for the state-dependent, centroidal dynamic constraints inherent to legged robots. The method, of low dimension, formulated as a Linear Program, is really efficient to compute, and can find an application in various problems related to legged locomotion. By incorporating this steering method into an existing sampling-based contact planner, we propose the first kinodynamic contact planner for legged robots.

139335
17049
21/03/2017

Optimal design of compliant walkers

G.BUONDONNO, J.CARPENTIER, G.SAUREL, N.MANSARD, A.DE LUCA, J.P.LAUMOND

Rome, GEPETTO, Univ of Cambridge

Rapport LAAS N°17049, Mars 2017, 7p.

Lien : https://hal.archives-ouvertes.fr/hal-01483567

Diffusable

Plus d'informations

Abstract

We present an optimization framework for the design and analysis of underactuated biped walkers, characterized by passive or actuated joints with rigid or non-negligible elastic actuation/transmission elements. The framework is based on optimal control, dealing with geometric constraints and various dynamic objective functions, as well as boundary conditions, which helps in selecting optimal values both for the actuation and the transmission parameters. Solutions of the formulated problems are shown for different kinds of bipedal architectures, and comparisons drawn between traditional rigid robots and compliant ones show the energy-efficiency of compliant actuators in the context of locomotion.

139321
17045
16/03/2017

Quelle place pour les robots humanoïdes dans nos maisons ? Une perspective épistémologique et sociale.

B.TONDU

GEPETTO

Rapport LAAS N°17045, Mars 2017, 17p.

Lien : https://hal.archives-ouvertes.fr/hal-01481029

Diffusable

Plus d'informations

Résumé

La robotique humanoïde peut-être considérée comme le but ultime d’une robotisation dont le robot industriel ne serait qu’une étape. De même que l’on parle d’une I.A. « faible » et d’une I.A. « forte », nous proposons d’opposer une robotique faible qui serait celle des robots industriels et une robotique forte qui serait celle des robots humanoïdes dont la capacité gestuelle se confondrait avec la capacité gestuelle humaine. Notre univers domestique est fait de machines conçues pour remplacer le travail du geste humain par le travail d’une machine non anthropomorphe, dont l’archétype est la machine à laver. Le robot domestique devra donc apprendre le maniement de ces machines domestiques qui, à la différence de la tâche qu’elles sont censées mimer, exigent peu de puissance mais une grande diversité gestuelle. Comment penser le devenir de la robotique humanoïde de service face à cette exigence d’habileté manuelle ? Il est bien difficile d’y répondre comme il était, à l’époque, bien difficile de cerner l’évolution de l’I.A. Ce n’est, selon nous, que par tâtonnements successifs que la robotique humanoïde prouvera sa valeur, entre relative spécialisation et relative standardisation de son environnement domestique où elle est censée s’intégrer. Enfin, il est encore difficile de dire si, dans un premier temps au moins, la robotique humanoïde domestique sera plus ostentatoire que réellement utile.

139284
Les informations recueillies font l’objet d’un traitement informatique destiné à des statistiques d'utilisation du formulaire de recherche dans la base de données des publications scientifiques. Les destinataires des données sont : le service de documentation du LAAS.Conformément à la loi « informatique et libertés » du 6 janvier 1978 modifiée en 2004, vous bénéficiez d’un droit d’accès et de rectification aux informations qui vous concernent, que vous pouvez exercer en vous adressant à
Pour recevoir une copie des documents, contacter doc@laas.fr en mentionnant le n° de rapport LAAS et votre adresse postale. Signalez tout problème de dysfonctionnement à sysadmin@laas.fr. http://www.laas.fr/pulman/pulman-isens/web/app.php/