Investigating the Interaction between Helmet Field of View and Steering Behavior in a Novel Motorcycle Simulator

While helmet wearing reduces the severity of injuries in motorcycle crashes, it may also increase the likelihood of getting involved into a traffic accident through a reduction in the rider’s field of view. We thus investigated the perceptual effects of helmet wearing when riding a motorcycle. The task consisted of negotiating curves in a fixed-based simulator while the helmet visor vertical dimension and need to check the handlebar-mounted speedometer were manipulated. Decreasing the vertical aperture below roughly 30 deg significantly impaired a rider’s ability to maintain their lane position and speed; with the effect of aperture being significantly greater when speedometer checking was required. The present findings provide further support for near/far point models of steering and help to quantify the tradeoff between physical and perceptual effects in helmet design

Drivers' decision-making when attempting to cross an intersection results from choice between affordances

International audienceIn theory, a safe approach to an intersection implies that drivers can simultaneously manage two scenarios: they either choose to cross or to give way to an oncoming vehicle. In this article we formalize the critical time for safe crossing (CT cross) and the critical time for safe stopping (CT stop) to represent crossing and stopping possibilities, respectively. We describe these critical times in terms of affordances and empirically test their respective contribution to the driver's decision-making process. Using a driving simulator, three groups of participants drove cars with identical acceleration capabilities and different braking capabilities. They were asked to try to cross an intersection where there was an oncoming vehicle, if they deemed the maneuver to be safe. If not, they could decide to stop or, as a last resort, make an emergency exit. The intersections were identical among groups. Results showed that although the crossing possibilities (CT cross) were the same for all groups, there were between-group differences in crossing frequency. This suggests that stopping possibilities (CT stop) play a role in the driver's decision-making process, in addition to the crossing possibilities. These results can be accounted for by a behavioral model of decision making, and provide support for the hypothesis of choice between affordances

Perceptual-motor coupling betwwen Helicopter and ship during ship deck landing maneuvers

Helicopter ship landings are challenging operations appealing for further researches and innovations to help pilots safely dealing with a variety of environmental, visual and operational contexts. Indeed, landing on ship not only differs from land-based landings in the extent that the landing area is located on the flight deck, which is most of the time oscillating, but also because the visual environment is often impoverished (e.g., rain, fog, night conditions). In order to improve safety at deck-landing, the French Aerospace Lab (ONERA) and the French Defense Agency (DGA) are interested in understanding pilots’ perceptual-motor strategies involved in a such complex task so as to design ecological interfaces assisting pilots’ landing maneuvers

What level of analysis to detect expertise during basketball shooting in a virtual reality ?

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Tracking expertise in visual information pickup when throwing basketball using virtual reality

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Assistance vibrotactile à l'interception locomotrice de cibles mobiles : étude de faisabilité

Organisateurs : Université de Genève (Germain Poizat, Raphaël Maion, Simon Flandin), Haute Ecole Spécialisée de Suisse Occidentale (Carole Baudin, Bruno Parent, Rafaël Weissbrodt), Centre universitaire de médecine générale et de santé publique (Claire Bauduin), Centre hospitalier universitaire vaudois (Vera Bustamante) Hopitaux Universitaire de Genève (Christine Villaret), Optimance (David Bozier).International audienceCan we assist the locomotor actions of intercepting moving targets in the absence of visionusing a tactile sensory augmentation system? When the target to be intercepted is visible, a person canadjust their walking speed so as to null the rate of change of the angle between their direction and thetarget (maintaining constant bearing angle, CBA). We present technological developments and afeasibility study evaluating the usability of a tactile sensory augmentation device intended to assist thelocomotor actions of interception. Our results suggest that CBA coupling, which is naturally observedwhen vision is available, can be maintained when using our device, after a training period. We discussthe preliminary results of this study in the light of the experimental changes we will introduce into ourscientific program in the future.Peut-on assister les actions locomotrices d'interception de cibles mobiles en absence de vision grâce à un dispositif de suppléance sensorielle tactile ? Lorsque la cible à intercepter est visible, une personne peut ajuster sa vitesse de déplacement de façon à annuler le taux de changement de l'angle entre sa direction de déplacement et celle de la cible (constant bearing angle, CBA). Nous présentons ici les développements technologiques et une étude de faisabilité visant à évaluer l'utilisabilité d'un dispositif de suppléance sensorielle tactile destiné à assister les actions locomotrices d'interception. Nos résultats suggèrent que moyennant une période d'apprentissage, le couplage CBA, naturellement observé lorsque la vision est disponible peut être maintenu lors de l'utilisation de notre dispositif. Nous discutons les résultats préliminaires de cette étude au regard des changements expérimentaux que nous introduirons à l'avenir dans notre programme scientifique

Is perception of self-motion speed a necessary condition for intercepting a moving target while walking?

International audienceWhile it has been shown that the Global Optic Flow Rate (GOFR) is used in the control of self-motion speed, this study examined its relevance in the control of interceptive actions while walking. We asked participants to intercept approaching targets by adjusting their walking speed in a virtual environment, and predicted that the influence of the GOFR depended on their interception strategy. Indeed, unlike the Constant Bearing Angle (CBA), the Modified Required Velocity (MRV) strategy relies on the perception of self-displacement speed. On the other hand, the CBA strategy involves specific speed adjustments depending on the curvature of the target's trajectory, whereas the MRV does not. We hypothesized that one strategy is selected among the two depending on the informational content of the environment. We thus manipulated the curvature and display of the target's trajectory, and the relationship between physical walking speed and the GOFR (through eye height manipulations). Our results showed that when the target trajectory was not displayed, walking speed profiles were affected by curvature manipulations. Otherwise, walking speed profiles were less affected by curvature manipulations and were affected by the GOFR manipulations. Taken together, these results show that the use of the GOFR for intercepting a moving target while walking depends on the informational content of the environment. Finally we discuss the complementary roles of these two perceptual-motor strategies

Prospective control of free-throw in basketball: Validation of a virtual setup and de-correlation methodology

International audiencePrevious basketball studies are unclear on whether free throws are pre-programmed (Vickers, 1996) or regulated online (de Oliveira, Huys, Oudejans, van de Langenberg, & Beek, 2007). In line with the law of control framework (Warren, 1988), we are in favor the second solution. This would imply that visual information concerning the sufficiency of the current movement to score a basket should so as to correct the movement pattern if necessary. While eye-tracking measurements or visual occlusion methodology have provided strong evidences in favor of the online hypothesis, biasing visual perception by mean of virtual reality should ultimately settle the issue

Assistance vibrotactile à l'interception locomotrice de cibles mobiles : étude de faisabilité

International audiencePeut-on assister les actions locomotrices d'interception de cibles mobiles en absence de vision grâce à un dispositif de suppléance sensorielle tactile ? Lorsque la cible à intercepter est visible, une personne peut ajuster sa vitesse de déplacement de façon à annuler le taux de changement de l'angle entre sa direction de déplacement et celle de la cible (constant bearing angle, CBA). Nous présentons ici les développements technologiques et une étude de faisabilité visant à évaluer l'utilisabilité d'un dispositif de suppléance sensorielle tactile destiné à assister les actions locomotrices d'interception. Nos résultats suggèrent que moyennant une période d'apprentissage, le couplage CBA, naturellement observé lorsque la vision est disponible peut être maintenu lors de l'utilisation de notre dispositif. Nous discutons les résultats préliminaires de cette étude au regard des changements expérimentaux que nous introduirons à l'avenir dans notre programme scientifique

Effet du champ de vision sur le comportement de conduite en moto : implication pour la conception des casques

International audienceWhile helmet wearing reduces the severit of injuries in motorcycle crashes, it may also increase the likelihood of getting involved into a traffic accident through a reduction in the rider’s field of view. We thus investigated the perceptual effects of helmet wearing when riding a motorcycle. The task consisted of negotiating curves in a fixed-based motorbike simulator while the helmet visor vertical dimension and need to check the handlebar-mounted speedometer were manipulated. Decreasing the vertical aperture below roughly 30 deg significantly impaired a rider’s ability to maintain their lane position and speed; with the effect of aperture being significantly greater when speedometer checking was required. The present findings help to quantify the tradeoff between physical and perceptual effects in helmet design.Si le port du casque est le moyen le plus efficace pour limiter la gravité des accidents de moto, il pourrait également augmenter le risque d’être impliqué dans un accident puisqu’il limite le champ de vision du motard. Nous avons analysé ici l’effet d’une manipulation du champ de vision sur le comportement de conduite en moto. La tâche consistait à négocier des virages sur un simulateur de moto à base fixe, alors que la hauteur de l’ouverture du casque et la nécessité de contrôler sa vitesse sur un compteur fixé sur le guidon étaient manipulées. Des ouvertures de casque inférieures à 30 deg. environ dégradaient la capacité du conducteur à maintenir sa vitesse et sa position dans la voie; cet effet était d’autant plus marqué dans les conditions impliquant de regarder le compteur de vitesse. Ces résultats ont des implications directes quant à la gestion du compromis entre les contraintes physique et perceptive dans la conception de casques de moto