A Case Study on Vestibular Sensations in Driving Simulators

Motion platforms have been used in simulators of all types for several decades. Since it is impossible to reproduce the accelerations of a vehicle without limitations through a physically limited system (platform), it is common to use washout filters and motion cueing algorithms (MCA) to select which accelerations are reproduced and which are not. Despite the time that has passed since their development, most of these algorithms still use the classical washout algorithm. In the use of these MCAs, there is always information that is lost and, if that information is important for the purpose of the simulator (the training simulators), the result obtained by the users of that simulator will not be satisfactory. This paper shows a case study where a BMW 325Xi AUT fitted with a sensor, recorded the accelerations produced in all degrees of freedom (DOF) during several runs, and data have been introduced in mathematical simulation software (washout + kinematics + actuator simulation) of a 6DOF motion platform. The input to the system has been qualitatively compared with the output, observing that most of the simulation adequately reflects the input to the system. Still, there are three events where the accelerations are lost. These events are considered by experts to be of vital importance for the outcome of a learning process in the simulator to be adequat

Phase-Linking and the Perceived Motion during Off-Vertical Axis Rotation

Human off-vertical axis rotation (OVAR) in the dark typically produces perceived motion about a cone, the amplitude of which changes as a function of frequency. This perception is commonly attributed to the fact that both the OVAR and the conical motion have a gravity vector that rotates about the subject. Little-known, however, is that this rotating-gravity explanation for perceived conical motion is inconsistent with basic observations about self-motion perception: (a) that the perceived vertical moves toward alignment with the gravito-inertial acceleration (GIA) and (b) that perceived translation arises from perceived linear acceleration, as derived from the portion of the GIA not associated with gravity. Mathematically proved in this article is the fact that during OVAR these properties imply mismatched phase of perceived tilt and translation, in contrast to the common perception of matched phases which correspond to conical motion with pivot at the bottom. This result demonstrates that an additional perceptual rule is required to explain perception in OVAR. This study investigates, both analytically and computationally, the phase relationship between tilt and translation at different stimulus rates—slow (45°/s) and fast (180°/s), and the three-dimensional shape of predicted perceived motion, under different sets of hypotheses about self-motion perception. We propose that for human motion perception, there is a phase-linking of tilt and translation movements to construct a perception of one’s overall motion path. Alternative hypotheses to achieve the phase match were tested with three-dimensional computational models, comparing the output with published experimental reports. The best fit with experimental data was the hypothesis that the phase of perceived translation was linked to perceived tilt, while the perceived tilt was determined by the GIA. This hypothesis successfully predicted the bottom-pivot cone commonly reported and a reduced sense of tilt during fast OVAR. Similar considerations apply to the hilltop illusion often reported during horizontal linear oscillation. Known response properties of central neurons are consistent with this ability to phase-link translation with tilt. In addition, the competing “standard” model was mathematically proved to be unable to predict the bottom-pivot cone regardless of the values used for parameters in the model

A Mixed Method Approach to Collegiate Aviation Self-Assessment of G-Load on Landing: Pilot Perception Versus Reality

Because there is no universal definition of a hard landing, pilots themselves must determine if a landing was hard enough to require an unscheduled maintenance inspection. Large, transport category aircraft are equipped with flight data monitoring (FDM) as a secondary data source that can help pilots determine if a hard landing occurred, but FDM is not commonplace in general aviation. It is important for a pilot to be able to differentiate between a firm landing that does not cause damage to the aircraft and hard landing that potentially could cause damage to the aircraft by means of vestibular, visual, and proprioceptive cues. Self-assessment of these cues helps pilots determine if the landing should be considered a hard landing. Self-assessments are subjective and depending upon metacognitive level, a pilot may fall prey to self-serving bias. To determine if self-serving bias is present in the aviation domain, participants completed a survey on landing perceptions. Additionally, flight data monitoring equipment provided actual landing data. Results suggest that self-serving bias is not common in the aviation domain unlike existing literature suggests. Many participants were unable to accurately perceive landing G-load, indicating that FDM equipment provides reliable data

Etude des lois de commande de la plateforme de simulation de conduite et influence sur le mal de simulateur

La simulation de conduite est fortement utilisée dans la recherche et le développement pour l'industrie automobile. Les simulateurs de conduite sont utilisés pour évaluer les prototypes véhicules pour la dynamique du véhicule et les systèmes d'aide à la conduite. Cependant, l'utilisation des simulateurs de conduite induit une problématique scientifique qui peut limiter son développement. En raison de son principe même, le simulateur de conduite ne restitue pas des mouvements du véhicule à l'échelle 1. Ce verrou cause des phénomènes de mal du simulateur qu'il est important d'étudier.Cette thèse propose d'étudier des méthodes et outils à mettre en œuvre dans les simulateurs de conduite statique ou dynamique. De cette mise en œuvre, des études sur le mal du simulateur sont menées grâce à des mesures objectives (via un capteur de suivi de mouvement, plate-forme de stabilité du corps, électromyographie) et subjectives (par l'intermédiaire de questionnaires). Des solutions algorithmiques et matérielles sont proposées et évaluées dans le contexte de la simulation de conduite.Les approches proposées dans cette thèse pour réduire le mal du simulateur sont:- Elaborer et évaluer les algorithmes de contrôle de la plate-forme mobile hexapode: sept algorithmes différents sont mis en œuvre.- Mesurer les effets liés au mal de simulateur sur les sujets aux niveaux vestibulaire, neuromusculaire et posturale.- Evaluer l'influence de l'implication des sujets sur le mal de simulateur (conducteurs et passagers).Simulation has been intensively involved nowadays in research and development for automotive industry. Driving simulators are one of those simulation techniques which are used to evaluate the prototypes for the vehicle dynamics and driving assistance systems. However with the driving simulator, there is a lock associated with its use. Because representing a permanent scenario as scale 1 is quite difficult. Because of that difficulty, motion/simulator sickness is an inevitably important topic to study.This thesis proposes to explore methods and tools to implement in static or dynamic simulators. In this implementation, studies of simulator sickness are conducted with objective measures (via a motion tracking sensor, platform for body stability, electromyography) and subjective (through questionnaires). These algorithmic or hardware solutions studies should be defined and applied at simulators. The proposed approaches to reduce or avoid simulator sickness in this thesis are:- Building control algorithms of motion hexapod platform: seven different algorithms are implemented.- Measuring the effects of inertia on subjects at vestibular, neuromuscular and postural levels.- Assessing the involvement of subjects (drivers and passengers).PARIS-Arts et Métiers (751132303) / SudocSudocFranceF

Visually induced motion sickness

At times, people exposed to moving visual scenes may perceive themselves as moving even though they are, in fact, stationary. This sensation is sometimes experienced by people sitting in a railway carriage, in a station, when a neighbouring train slowly pulls away. Rather than sensing that the other train is leaving the station, they have the compelling feeling that their own train is moving in the opposite direction. This phenomenon, the feeling of moving brought about solely by a change in the visual scene, is called vection. Sustained exposure to moving visual scenes may not only produce vection, but can also provoke signs and symptoms of motion sickness such as dizziness, sweating, stomach awareness, and nausea and these adverse effects are now generally termed "visually induced motion sickness" (VIMS). VIMS is frequently reported in a variety of simulated or virtual environments such as flight and driving simulators, as well as in other contexts, such as at the cinema. It not only constitutes a nuisance to the user of these technologies, but also limits the usability of these technologies. Unlike other forms of motion sickness, such as seasickness, little is known about what conditions, or what aspects of moving visual scenes, are particularly provocative. Furthermore, research conducted thus far has generally investigated rotational motion patterns that are not representative of motion typically encountered in the real world. As a consequence, the work presented here has investigated the interrelationship between visual stimulus characteristics, VIMS, and vection during simulated forward and backward selfmotion (Le. along the fore-and-aft axis). In the first study, individuals were exposed to moving visual scenes that induced an illusion of motion in the fore-and-aft axis. These were presented either at a constant speed, or at a sinusoidally varying speed. Although varying the speed was expected to lead to higher levels of VIMS, this was not observed. The absence of an increased level of VIMS was hypothesised to be a consequence of the particular frequency employed (0.025 Hz). The frequency dependence of VI MS was then tested in a series of experiments. Noting that amplitude and acceleration covaried with frequency, it was found that within the range 0.025 - 1.6 Hz, VIMS peaked at 0.2 Hz. Using motion profiles with varying amplitude and acceleration, studies employing angular motion stimulation, on the other hand, had previously shown a peak in VIMS to occur at a frequency of approximately 0.06 Hz. This suggests that results obtained with angular motion stimulation cannot be extrapolated to scenarios involving linear motion stimulation in the fore-and-aft axis. The studies thus far isolated the effect of stimulus characteristics by preventing eye movements from occurring by means of fixation. A further study was conducted with the express purpose of investigating the effect of gaze shifting. It was found that the level of VIMS significantly increased with fixation away from the focus of expansion of a radial display. This suggests that the visual stimulus interacts differently with different portions of the retina. Real-world motion scenarios generally entail motion along different axes simultaneously. Most studies into VIMS have been restricted to single-axis motion and, although VIMS is assumed to increase with more complex motion scenarios, little is known about how VIMS changes with·increasing complexity. Comparing single- versus dual-axis motion, it was unexpectedly found that dualaxis motion did not lead to higher levels of VIMS, challenging the generally held assumption that VIMS is proportional to the degree of sensory conflict. The feasibility of predicting the incidence of VIMS based on an individual's motion sickness history as assessed by the revised Motion Sickness Susceptibility Questionnaire (MSSQ) was finally explored. Correlation coefficients were comparable to those observed with true motion suggestive of a common underlying mechanism between different forms of motion sickness. For the prediction of individual behaviour, the MSSQ was found to be of limited value in its current form. . A general finding was that vection consistently preceded the occurrence of VIMS, in line with the idea that vection is a necessary condition for VIMS to occur. This implies that future displays optimising the simulation of self-motion are likely to result in higher levels of VIMS. In addition, the findings that frequency, gaze direction, and multi-axis motion affected VIMS differently with simulated motion in the fore-and-aft axis as compared to angular motion profiles, indicate that angular motion commonly used to study VIMS may be of limited value.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Visually induced motion sickness

At times, people exposed to moving visual scenes may perceive themselves as moving even though they are, in fact, stationary. This sensation is sometimes experienced by people sitting in a railway carriage, in a station, when a neighbouring train slowly pulls away. Rather than sensing that the other train is leaving the station, they have the compelling feeling that their own train is moving in the opposite direction. This phenomenon, the feeling of moving brought about solely by a change in the visual scene, is called vection. Sustained exposure to moving visual scenes may not only produce vection, but can also provoke signs and symptoms of motion sickness such as dizziness, sweating, stomach awareness, and nausea and these adverse effects are now generally termed "visually induced motion sickness" (VIMS). VIMS is frequently reported in a variety of simulated or virtual environments such as flight and driving simulators, as well as in other contexts, such as at the cinema. It not only constitutes a nuisance to the user of these technologies, but also limits the usability of these technologies. Unlike other forms of motion sickness, such as seasickness, little is known about what conditions, or what aspects of moving visual scenes, are particularly provocative. Furthermore, research conducted thus far has generally investigated rotational motion patterns that are not representative of motion typically encountered in the real world. As a consequence, the work presented here has investigated the interrelationship between visual stimulus characteristics, VIMS, and vection during simulated forward and backward selfmotion (Le. along the fore-and-aft axis). In the first study, individuals were exposed to moving visual scenes that induced an illusion of motion in the fore-and-aft axis. These were presented either at a constant speed, or at a sinusoidally varying speed. Although varying the speed was expected to lead to higher levels of VIMS, this was not observed. The absence of an increased level of VIMS was hypothesised to be a consequence of the particular frequency employed (0.025 Hz). The frequency dependence of VI MS was then tested in a series of experiments. Noting that amplitude and acceleration covaried with frequency, it was found that within the range 0.025 - 1.6 Hz, VIMS peaked at 0.2 Hz. Using motion profiles with varying amplitude and acceleration, studies employing angular motion stimulation, on the other hand, had previously shown a peak in VIMS to occur at a frequency of approximately 0.06 Hz. This suggests that results obtained with angular motion stimulation cannot be extrapolated to scenarios involving linear motion stimulation in the fore-and-aft axis. The studies thus far isolated the effect of stimulus characteristics by preventing eye movements from occurring by means of fixation. A further study was conducted with the express purpose of investigating the effect of gaze shifting. It was found that the level of VIMS significantly increased with fixation away from the focus of expansion of a radial display. This suggests that the visual stimulus interacts differently with different portions of the retina. Real-world motion scenarios generally entail motion along different axes simultaneously. Most studies into VIMS have been restricted to single-axis motion and, although VIMS is assumed to increase with more complex motion scenarios, little is known about how VIMS changes with·increasing complexity. Comparing single- versus dual-axis motion, it was unexpectedly found that dualaxis motion did not lead to higher levels of VIMS, challenging the generally held assumption that VIMS is proportional to the degree of sensory conflict. The feasibility of predicting the incidence of VIMS based on an individual's motion sickness history as assessed by the revised Motion Sickness Susceptibility Questionnaire (MSSQ) was finally explored. Correlation coefficients were comparable to those observed with true motion suggestive of a common underlying mechanism between different forms of motion sickness. For the prediction of individual behaviour, the MSSQ was found to be of limited value in its current form. . A general finding was that vection consistently preceded the occurrence of VIMS, in line with the idea that vection is a necessary condition for VIMS to occur. This implies that future displays optimising the simulation of self-motion are likely to result in higher levels of VIMS. In addition, the findings that frequency, gaze direction, and multi-axis motion affected VIMS differently with simulated motion in the fore-and-aft axis as compared to angular motion profiles, indicate that angular motion commonly used to study VIMS may be of limited value.EThOS - Electronic Theses Online ServiceGBUnited Kingdo