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La recherche a montré que l’interaction avec les surfaces peut bénéficier de l’ajout de retour haptique. La perception de cette retour haptique est influencée par d’autres modalités, telles que visuelles et auditives, ce qui permet de le renforcer ou de l’enrichir. Cependant, l’effet des textures 3D dans la réalité augmentée (AR), comme le rendu stéréoscopique et la déformation de surface, sur la perception tactile des textures n’a pas encore été étudié, en particulier dans une condition tactile active. Dans cet article, nous étudions l’interaction perceptuelle entre la stéréoscopie, la déformation de surface et la retour haptique dans un état actif. La retour haptique a été mise en oeuvre en utilisant une modulation par friction basée sur des vibrations à ultrasons, tandis que la retour visuelle a été implémentée avec une paire de lunettes 3D en AR. L’étude expérimentale est une exploration visuelle-tactile d’une texture virtuelle. Notre objectif est de comprendre l’interaction d’une modalité sur l’autre pour la rugosité et la perception de la profondeur. Nous avons demandé aux participants de porter des jugements de rugosité de texture visuelle et tactile et d’estimer la profondeur de la déformation de la texture sous leurs doigts. Nos résultats suggèrent que : 1) la rugosité tactile perçue peut être modifiée en ajoutant un rendu stéréoscopique et / ou une déformation de surface visuelle mais uniquement pour les textures tactiles lisses. 2) La rugosité visuelle perçue peut être modifiée en augmentant la rugosité tactile. 3) La rugosité globale (visuel + tactile) est principalement impactée par la perception tactile. Research has shown that interaction with tactile surfaces can benefit from the addition of haptic feedback. The perception of this feedback is influenced by other modalities, visual and auditory, making it possible to reinforce or enrich it. However, the effect of visual depth cues, such as stereoscopic rendering and surface deformation, on the tactile perception of textures has not been studied yet, especially in an active touch condition. In this paper, we investigate the perceptual interaction between stereoscopy, surface deformation, and haptic feedback in the condition of active touch implemented using friction modulation based on ultrasonic vibrations. The experimental study is based on a Visual-Tactile exploration of a virtual texture. Our objective is to understand the interaction of one modality over the other for roughness and depth perception. Participants were asked to make visual and tactile texture roughness judgments and to estimate the depth of deformation of the texture below their fingers. Our results suggest that: 1) perceived tactile roughness can be modified by adding stereoscopic rendering and/or visual surface deformation but only for smooth tactile textures, 2) perceived visual roughness can be modified by increasing the tactile roughness, 3)the overall roughness (Visual + Tactile) is mainly impacted by the tactile perception.

International audience

International audience; This work presents the control of a piezoelectric interface that combines two vibration modes of a plate to render the haptic feeling of a button click. By principle, the two vibration modes create an elliptical motion of particles of a beam that can induce a lateral force to the fingerpulp. In this device, the synchronization of the modes’ vibrations is essential, and can be obtained with a closed loop control. In the paper, we present the control in the (d,q) frame, because it can ensure the dynamic performances to achieve a compelling haptic feedback, yet being robust besides the external disturbances produced by the user’s finger. The proposed method could achieve a 2 ms response time, and the haptic feedback was perceived by 100% of users in a psychophysical study.

International audience

International audience

The Essaouira-Agadir Basin (EAB, Morocco) presents numerous and well-exposed outcrops of the Lower Cretaceous series. Here we present an integrated stratigraphic framework for the latest Barremian-early Albian, and for the western Tethys based on i) the identification of sedimentary discontinuities, ii) the establishment of a high-resolution ammonite and calcareous nannofossil biozonation, and iii) a carbon isotope record. Various sedimentary discontinuities corresponding to erosive surfaces were recognized within these deposits. Most of these surfaces are correlated within the EAB, and correspond to drops in sea level. The distribution of ammonite assemblages was calibrated with the standard Mediterranean zonation. Several ammonite index-species have been identified, in particular for the early Aptian and earliest late Aptian. This was crucial because the lower series are dominated by condensed sedimentation and temporal hiatuses. Most of the uppermost Barremian to lower Albian ammonite standard zones have been recognized. Four new and reliable calcareous nannofossil bioevents have been identified in the late Aptian allowing to revise the NC7 Zone. The taxonomic criteria used to define species markers of both NC8A and NC8B subzones have been specified, thereby improving the calibration of these subzones with ammonite biozones. The delta C-13(carb) values from whole rock samples decrease from the late Aptian to the early Albian. The new biostratigraphic and chemostratigraphic scheme for the EAB allowed rather good correlations between sections from southern and northern Tethyan margins.