Synchronisation et calibrage entre un Lidar 3D et une centrale inertielle pour la localisation précise d'un véhicule autonome

International audienceLaser remote sensing (Lidar) is a technology increasingly used especially in the perception layers of autonomous vehicles. As the vehicle moves during measurement, Lidar data must be referenced in a fixed frame which is usually done thanks to an inertial measurement unit (IMU). However, these sensors are not designed to work together natively thus it is necessary to synchronize and calibrate them carefully. This article presents a method for characterizing timing offsets between a 3D Lidar and an inertial measurement unit. It also explains how to implement the usual methods for pose estimation between an IMU and a Lidar when using such sensors in real conditions.La télédétection par laser (Lidar) est une technologie de plus en plus utilisée en particulier dans les fonctions de perception et localisation nécessaires à la conduite autonome. L'acquisition des données Lidar doit être couplée à la mesure du mouvement du véhicule par une centrale inertielle. Ces capteurs n'étant pas conçus pour fonctionner ensemble nativement, il est nécessaire de maitriser leur synchronisation et leur calibrage géométrique. Cet article présente une méthode pour caractériser les décalages temporels entre un Lidar 3D et une centrale inertielle. Il explique aussi comment mettre en œuvre les méthodes de la littérature pour le calcul de la pose entre centrale inertielle et Lidar sur un véhicule utilisé en conditions réelles

DNA Damage Mediated S and G2 Checkpoints in Human Embryonal Carcinoma Cells

For mouse embryonic stem (ES) cells, the importance of the S and G2 cell cycle checkpoints for genomic integrity is increased by the absence of the G1 checkpoint. We have investigated ionizing radiation (IR)-mediated cell cycle checkpoints in undifferentiated and retinoic acid-differentiated human embryonal carcinoma (EC) cells. Like mouse ES cells, human EC cells did not undergo G1 arrest after IR but displayed a prominent S-phase delay followed by a G2-phase delay. In contrast, although differentiated EC cells also failed to arrest at G1-phase after IR, they quickly exited S-phase and arrested in G2-phase. In differentiated EC cells, the G2-M-phase cyclin B1/CDC2 complex was upregulated after IR, but the G1-S-phase cyclin E and the cyclin E/CDK2 complex were expressed at constitutively low levels, which could be an important factor distinguishing DNA damage responses between undifferentiated and differentiated EC cells. S-phase arrest and expression of p21 could be inhibited by 7-hydroxystaurosporine, suggesting that the ataxia-telangiectasia and Rad-3-related-checkpoint kinase 1 (ATR-CHK1), and p21 pathways might play a role in the IR-mediated S-phase checkpoint in EC cells. IR-mediated phosphorylation of ataxia-telangiectasia mutated, (CHK1), and checkpoint kinase 2 were distinctly higher in undifferentiated EC cells compared with differentiated EC cells. Combined with the prominent S and G2 checkpoints and a more efficient DNA damage repair system, these mechanisms operate together in the maintenance of genome stability for EC cells. Stem Cells 2009;27:568–57

Stress path during pressuremeter test and link between shear modulus and Menard pressuremeter modulus in unsaturated fine soils

This paper presents the stress path before and during a pressumeter test using a Modified Cam-Clay model. This model have been used for unsaturated clay with continuous water phase (D2 domain according to Boutonnier 2007) and for silty to clayey soils with discontinuous water phase (D1 domain – ibid.). After reminding the stress distribution around a pressuremeter cell and the meaning of the Menard pressuremeter modulus which is linked to the soil shear modulus, we explain the stress state during pressuremeter modulus measurement. Then, we show that this stress path diagram can be used to explain classical observations made using Menard pressuremeter tests in continental area and typically: Measurement of high ratio “Menard pressuremeter modulus / pressuremeter limit pressure” in clay subjected to drought

Stress path during pressuremeter test and link between shear modulus and Menard pressuremeter modulus in unsaturated fine soils

This paper presents the stress path before and during a pressumeter test using a Modified Cam-Clay model. This model have been used for unsaturated clay with continuous water phase (D2 domain according to Boutonnier 2007) and for silty to clayey soils with discontinuous water phase (D1 domain – ibid.). After reminding the stress distribution around a pressuremeter cell and the meaning of the Menard pressuremeter modulus which is linked to the soil shear modulus, we explain the stress state during pressuremeter modulus measurement. Then, we show that this stress path diagram can be used to explain classical observations made using Menard pressuremeter tests in continental area and typically: Measurement of high ratio “Menard pressuremeter modulus / pressuremeter limit pressure” in clay subjected to drought. Limit pressure and Ménard pressuremeter modulus variation with respect to drought in silty clay situated in water-table fluctuation area. Finally, we will try to show the consequences of these stress paths for performing and interpreting pressuremeter test in unsaturated and collapsible soils

InHARD - Industrial Human Action Recognition Dataset in the Context of Industrial Collaborative Robotics

International audienceNowadays, humans and robots are working more closely together. This increases business productivity and product quality, leading to efficiency and growth. However, human and robot collaboration is rather static; robots move to a specific position then humans perform their tasks while being assisted by the robots. In order to get a dynamic collaboration, robots need to understand the human’s intention and learn to recognize the performed actions complementing therefore his capabilities and relieving him of arduous tasks. Consequently, there is a need for a human action recognition dataset for Machine Learning algorithms. Currently available depth-based and RGB+D+S based human action recognition datasets have a number of limitations, counting the lack of training samples along with distinct class labels, camera views, diversity of subjects and more importantly the absence of actual industrial human actions in an industrial environment. Actual action recognition datasets include simple daily, mutual, or healthrelated actions. Therefore, in this paper we introduce an RGB+S dataset named “Industrial Human Action Recognition Dataset” (InHARD) from a real-world setting for industrial human action recognition with over 2 million frames, collected from 16 distinct subjects. This dataset contains 13 different industrial action classes and over 4800 action samples. The introduction of this dataset should allow us the study and development of various learning techniques for the task of human actions analysis inside industrial environments involving human robot collaborations

Inoovas - Industrial ontology for operation in virtual and augmented scene: The architecture

International audienceDigitalization of industry brings new usage perspectives of digital tools as Virtual Reality (VR) and Augmented Reality (AR). However there is still open issue for integrating their usage into information system workflow of the industry. Therefore the paper proposes a workflow and an ontology based on the collaborators’ skills to allow the authoring of AR and VR operation guide instead of paper one. The paper gives an example based on the proposed ontology

Particle filter meets hybrid octrees: an octree-based ground vehicle localization approach without learning

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A use case study comparing augmented reality (AR) and electronic document-based maintenance instructions considering tasks complexity and operator competency level

International audienceAugmented reality (AR) is more and more used in the industrial context for maintenance, assembly operation. However, owing to the evolution and maturity of the technology, it is still necessary to evaluate the usage and benefits of AR in an industrial context to go further than proof of concept. As such, this paper proposes an analysis of AR case study in the literature. Then, this paper presents a methodology for comparing AR and electronic document-based complex maintenance instructions considering tasks complexity and operator competency level. The main results show that the consultation duration of the AR tablet is 34% statistically faster than the PDF tablet. It also shows that error concerning similar objects is reduced thanks to AR. Moreover, the study specifically focuses on types of task that worth using AR. However, the study shows that usability of the AR device is less well rated than the PDF for “beginner–intermediate” operators. Finally, an in-depth analysis permits extracting recommendations of the different factors to take into account with industrial AR applications

Synchronisation et calibrage entre un Lidar 3D et une centrale inertielle pour la localisation précise d'un véhicule autonome

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Synchronisation et calibrage entre un Lidar 3D et une centrale inertielle pour la localisation précise d'un véhicule autonome GEOLOCALISATION ET NAVIGATION Synchronisation et calibrage entre un Lidar 3D et une centrale inertielle pour la localisation precise d'un véhicule autonome Synchronization and calibration between a 3D Lidar and an inertial measurement unit for the accurate localization of an autonomous vehicle

Synchronisation et calibrage entre un Lidar 3D et une centrale inertielle pour la localisation précise d'un véhicule autonom