Laboratoire d’analyse et d’architecture des systèmes
Y.AOUSTIN, C.CHEVALLEREAU, J.P.LAUMOND
Ouvrage (contribution) : Humanoid Robotics: A Reference, Springer, N°ISBN 978-94-007-6045-5, Octobre 2018 , N° 18021
Ouvrage (contribution) : Biomechanics of Anthropomorphic Systems, Springer, N°ISBN 978-3-319-93870-7, Octobre 2018 , N° 18101
Humanoid robots are challenging mechatronics structures with several interesting features. Choosing a humanoid robot to develop applications or pursue research in a given direction might be difficult due to the strong interdependence of the technical aspects. This paper aims at giving a general description of this interdependence and highlight the lessons learned from the impressive works conducted in the past decade. The reader will find in the annex a table synthesizing the characteristics of the most relevant humanoid robots. Without focusing on a specific application we consider two main classes of humanoid robots: the ones dedicated to industrial application and the ones dedicated to human-robot interaction. The technical aspects are described in a way which illustrates the humanoid robots bridging the gap between these two classes. Finally this paper tries to make a synthesis on recent technological developments 1. 1 Mechanical structure 1.1 General design principal Humanoid robots are complex mechatronic systems. As such, it is necessary to consider the the mechanical structure, the computational system and the algorithms as a whole and for a given application. The robot's size, weight and strength are important factors when designing its structure. Let us consider two general classes of applications: physical performances while doing motion generation and validation of biological and/or cognitive models. The ATLAS robot from Boston Dynamics is an example of the first category, while the Kenshiro robot  from Tokyo University is an example of the second category
T.SENTENAC, F.BUGARIN, B.DUCAROUGE, M.DEVY
Revue Scientifique : Advanced Engineering Informatics, Vol.38, pp.203-215, Octobre 2018 , N° 18184
In many industrial sectors, Non Destructive Testing (NDT) methods are used for the thermomechanical analysis of parts in assemblies of engines or reactors or for the control of metal forming processes. This article suggests an automated multi-view approach for the thermal 3D reconstruction required in order to compute 3D surface temperature models. This approach is based only on infrared cameras mounted on a Cartesian robot. The low resolution of these cameras associated to a lack of texture to infrared images require to use a global approach based first on an uncalibrated rectification and then on the simultaneous execution, in a single step, of the dense 3D reconstruction and of an extended self-calibration. The uncalibrated rectification is based on an optimization process under constraints which calculates the homographies without prior calculation of the Fundamental Matrix and which minimizes the projective deformations between the initial images and the rectified ones. The extended self-calibration estimates both the parameters of virtual cameras that could provide the rectified images directly, and the parameters of the robot. It is based on two criteria evaluated according to the noise level of the infrared images. This global approach is validated through the reconstruction of a hot object against a reference reconstruction acquired by a 3D scanner.
A.ESTANA, K.MOLLOY, M.VAISSET, N.SIBILLE, T.SIMEON, P.BERNADO, J.CORTES
CBS, RIS, IDEA
Revue Scientifique : Parallel Computing, Vol.77, pp.84-100, Septembre 2018, DOI 10.1016/j.parco.2018.06.005 , N° 18176
The study of the conformational energy landscape of a molecule is essential for the understanding of its physicochemical properties. This requires the exploration of a continuous, high-dimensional space to identify the most probable conformations and the transition paths between them. The problem is computationally difficult, in particular for highly-flexible biomolecules such as Intrinsically Disordered Proteins (IDPs). In recent years, a robotics-inspired algorithm called Transition-based Rapidly-exploring Random Tree (TRRT) has been proposed to solve this problem, and has been shown to provide good results with small and middle-sized biomolecules. Aiming to treat larger systems, we propose a hybrid strategy for the efficient parallelization of a multi-tree variant of TRRT, called Multi-TRRT, enabling an efficient execution in (possibly large) computer clusters. The parallel algorithm uses OpenMP multi-threading for computation inside each multi-core processor and MPI to perform the communication between processors. Results show a near-linear speedup for a wide range of cluster configurations. Although the paper mainly deals with the application of the proposed parallel algorithm to the investigation of biomolecules, the explanations concerning the methods are general, aiming to inspire future work on the parallelization of related algorithms.
V.WALTER, N.STAUB, M.SASKA, A.FRANCHI
Manifestation avec acte : IEEE International Conference on Automation Science and Engineering ( CASE ) 2018 du 20 août au 24 août 2018, Munich (Allemagne), Août 2018, 6p. , N° 18165
A novel vision-based approach for indoor/outdoor mutual localization on Unmanned Aerial Vehicles (UAVs) with low computational requirements and without external infrastructure is proposed in this paper. The proposed solution exploits the low natural emissions in the near-UltraViolet (UV) spectrum to avoid major drawbacks of the visible spectrum .Such approach provides much better reliability while being less computationally intensive. Working in near-UV requires active markers, which can be leveraged by enriching the information content through blinking patterns encoded marker-ID. In order to track the markers motion and identify their blinking frequency, we propose an innovative use of three dimensional Hough Transform, applied to stored position-time points. The proposed method was intensively tested onboard multi-UAV systems in real-world scenarios that are very challenging for visible-spectrum methods.The results of our methods in terms of robustness, reliability and precision, as well as the low requirement on the system deployment, predestine this method to be an enabling technology for using swarms of UAVs.
O.STASSE, K.GIRAUD ESCLASSE, E.BROUSSE, M.NAVEAU, R.REGNIER, G.AVRIN, P.SOUERES
GEPETTO, LNE, Max Planck
Rapport LAAS N°18212, Août 2018, 24p.
In this paper we report results from a campaign of measurement in a laboratory allowing to put a humanoid robot HRP-2 in a controlled environment. We have investigated the effect of temperature variations on the robot capabilities to walk. In order to benchmark various motions modalities and algorithms we computed a set of performance indicators for bipedal locomotion. The scope of the algorithms for motion generation evaluated here is rather large as it spans analytical solutions to numerical optimization approaches able to realize real-time walking or multi-contacts.
A.BAROZET, M.BIANCIOTTO, T.SIMEON, H.MINOUX, J.CORTES
RIS, Sanofi-Aventis R&D
Revue Scientifique : Immunology Letters, Vol.200, pp.5-15, Août 2018 , N° 18175
Background: The existence of conformational changes in antibodies upon binding has been previously established. However, existing analyses focus on individual cases and no quantitative study provides a more global view of potential moves and repacking, especially on recent data. The present study focuses on analyzing the conformational changes in various antibodies upon binding, providing quantitative observations to be exploited for antibody-related modeling. Methods: Cartesian and dihedral Root-Mean-Squared Deviations were calculated for different subparts of 27 different antibodies, for which X-ray structures in the bound and unbound states are available. Elbow angle variations were also calculated. Previously reported results of four docking algorithms were condensed into one score giving overall docking success for each of 16 antibody-antigen cases. Results: Very diverse movements are observed upon binding. While many loops stay very rigid, several others display side-chain repacking or backbone rearrangements, or both, at many different levels. Large conformational changes restricted to one or more antibody hypervariable loops were found to be a better indicator of docking difficulty than overall conformational variation at the antibody-antigen interface. However, the failure of docking algorithms on some almost-rigid cases shows that scoring is still a major bottleneck in docking pose prediction. Conclusions: This study is aimed to help scientists working on antibody analysis and design by giving insights into the nature and the extent of conformational changes at different levels upon antigen binding.
F.FORGET, K.GIRAUD ESCLASSE, R.GELIN, N.MANSARD, O.STASSE
Manifestation avec acte : International Conference on Informatics in Control, Automation and Robotics ( ICINCO ) 2018 du 29 juillet au 31 juillet 2018, Porto (Portugal), Juillet 2018, 8p. , N° 17069
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.
F.BAILLY, E.POUYDEBAT, B.WATIER, V.BELS, P.SOUERES
GEPETTO, MECADEV, ISYEB
Manifestation avec acte : International Conference on Biomimetic and Biohybrid Systems ( Living Machines ) 2018 du 17 juillet au 20 juillet 2018, Paris (France), Juillet 2018, 12p. , N° 18135
This paper presents an interdisciplinary study of the role of the head in multisensory integration and motor-control organization for the production of voluntary spatial actions. It combines elements from biology and engineering. First, morphological and behavioral characteristics of animals able to perform voluntary spatial actions through evolution are examined. The complexity of state-space representation and observation of multi-joint mobile robots is then described in the context of automatic control, and perception-related characteristics brought by the presence of a head are presented from the perspective of signal processing. Finally, the role of the head in locomotion and manipulation for animals and robots is discussed, paving the way for future robot design.
M.TOGNON, E.CATALDI, H.TELLO CHAVEZ, G.ANTONELLI, J.CORTES, A.FRANCHI
Revue Scientifique : IEEE Robotics and Automation Letters, Vol.3, N°3, pp.2478-2484, Juillet 2018, DOI 10.1109/LRA.2018.2803206 , N° 18033
This paper presents a new method to address the problem of task-constrained motion planning for aerial manipulators. We propose a control-aware planner based on the paradigm of tight coupling between planning and control. Such paradigm is especially useful in aerial manipulation, where the separation between planning and control is not advisable. The proposed sampling based motion planner uses a controller composed of a second-order inverse kinematics algorithm and a dynamic tracker, as a local planner, thus allowing a more natural consideration of the closed-loop system dynamics. For task constrained motions, this method lets to i) sample directly in the reduced and more relevant task space, ii) predict the behavior of the controller avoiding motions that bring to singularities or large tracking errors, and iii) guarantee the correct execution of the maneuver. The method is tested in simulation for a multidirectional-thrust vehicle endowed with a two-DoF manipulator. The proposed approach is very general, and could be applied to ground and underwater robotic systems to perform manipulation or inspection tasks.