SAM

The role of motion platform on postural instability and head vibration exposure at driving simulators

AYKENT, Baris — Tue, 01 Jan 2013 00:00:00 GMT

The role of motion platform on postural instability and head vibration exposure at driving simulators AYKENT, Baris; PAILLOT, Damien; KEMENY, Andras; MERIENNE, Frédéric This paper explains the effect of a motion platform for driving simulators on postural instability and head vibration exposure. The sensed head level-vehicle (visual cues) level longitudinal and lateral accelerations (ax,sensed = ax_head and ay,sensed = ay_head, ayv = ay_veh and ayv = ay_veh) were saved by using a motion tracking sensor and a simulation software respectively. Then, associated vibration dose values (VDVs) were computed at head level during the driving sessions. Furthermore, the postural instabilities of the participants were measured as longitudinal and lateral subject body centre of pressure (XCP and YCP, respectively) displacements just after each driving session via a balance platform. The results revealed that the optic-head inertial level longitudinal accelerations indicated a negative non-significant correlation (r = −.203, p = .154 > .05) for the static case, whereas the optic-head inertial longitudinal accelerations depicted a so small negative non-significant correlation (r = −.066, p = .643 > .05) that can be negligible for the dynamic condition. The XCP for the dynamic case indicated a significant higher value than the static situation (t(47), p < .0001). The VDVx for the dynamic case yielded a significant higher value than the static situation (U(47), p < .0001). The optic-head inertial lateral accelerations resulted a negative significant correlation (r = −.376, p = .007 < .05) for the static platform, whereas the optic-head inertial lateral accelerations showed a positive significant correlation (r = .418, p = .002 < .05) at dynamic platform condition. The VDVy for the static case indicated a significant higher value rather than the dynamic situation (U(47), p < .0001). The YCP for the static case yielded significantly higher than the dynamic situation (t(47), p = .001 < 0.05).

Influence of a new discrete-time LQR-based motion cueing on driving simulator

AYKENT, Baris — Tue, 01 Jan 2013 00:00:00 GMT

Influence of a new discrete-time LQR-based motion cueing on driving simulator AYKENT, Baris; PAILLOT, Damien; KEMENY, Andras; MERIENNE, Frédéric This study proposes a method and an experimental validation to analyze dynamics response of the simulator's cabin and platform with respect to the type of the control used in the hexapod driving simulator. In this article, two different forms of motion platform tracking control are performed as a classical motion cueing algorithm and a discrete-time linear quadratic regulator (LQR) motion cueing algorithm. For each situation, vehicle dynamics and motion platform level data are registered from the driving simulation software. In addition, the natural frequencies of the roll accelerations are obtained in real-time by using FFT. The data are denoised by using wavelet 1D transformation. The results show that by using discrete-time LQR algorithm, the roll acceleration amplitudes that correspond to the natural frequencies and the total roll jerk have decreased at the motion platform level. Also, the natural frequencies have increased reasonably by using the discrete LQR motion cueing (1.5–2.2 Hz) compared with using the classical algorithm (0.4–1.5 Hz) at the motion platform, which is an indicator of motion sickness incidence avoidance. The literature shows that lateral motion (roll, yaw, etc.) in the frequency range of 0.1–0.5 Hz induces motion sickness. Furthermore, using discrete-time LQR motion cueing algorithm has decreased the sensation error (motion platform–vehicle (cabin) levels) two times in terms of total roll jerk. In conclusion, discrete-time LQR motion cueing has reduced the simulator sickness more than the classical motion cueing algorithm depending on sensory cue conflict theory.

Influence of Inertial Stimulus on Visuo-Vestibular Cues Conflict for Lateral Dynamics at Driving Simulators

AYKENT, Baris — Tue, 01 Jan 2013 00:00:00 GMT

Influence of Inertial Stimulus on Visuo-Vestibular Cues Conflict for Lateral Dynamics at Driving Simulators AYKENT, Baris; PAILLOT, Damien; KEMENY, Andras; MERIENNE, Frédéric This paper explains the effect of having an inertial stimulus (motion platform) for driving simulators on proximity to the reality for the sensed lateral dynamics with respect to the measurements and the perceptual fidelity using a questionnaire technique. To assess this objectively, the vestibular and vehicle level lateral accelerations (ay,sensed=ay_ vest, ayv =ay_veh ) were saved by using a motion tracking sensor and SCANeR studio software respectively. A confidence interval of 95% was chosen to test the correlations (Pearson’s correlation) and to fit models for the distributions of the visual-vestibular lateral accelerations with the multiple linear regression between the conditions of static (N=16) and dynamic (N=21) platform cases in terms of visuo-vestibular level lateral accelerations for the group of subjects (N=37). The results showed that the dynamic platform provides a higher lateral dynamics reality (positive correlation with an incidence of 90.48% for N=21) compared to the static configuration (negative correlation with an incidence of 50% for N=16) from Pearson’s correlation and a better fitted model and a lower visuo-vestibular cues’ conflict for the dynamic (R2 =0.429, the model is positive sloped, N=21) condition comparing to the static one (R2 =0.072, the model is negative sloped, N=16) from the multiple linear regression models. A two-tailed Mann Whitney U test yielded that the Ucomputed (2139)>Uexpected (1300.5) as p<0.0001, there was a significant difference between the sensed lateral acclerations for the static and dynamic platform cases. Disorientation related perception had positive correlations with the vestibular sensed lateral accelerations for the static condition whereas they were negatively correlated in the dynamic case. As conclusion, the dynamic platform presented a reduced level of motion sickness depending on the sensory conflict theory and the perception fidelity studies approved that dizziness was found to have a significant positive correlation with the vestibular level measured lateral acceleration in the static platform (r=0.293, p=0.037<0.05). Version éditeur de cet article : Aykent B, Merienne F, Paillot D, Kemeny A (2013) Influence of Inertial Stimulus on Visuo-Vestibular Cues Conflict for Lateral Dynamics at Driving Simulators. J Ergonomics 3: 113. doi:10.4172/2165-7556.1000113

A LQR washout algorithm for a driving simulator equipped with a hexapod platform : the relationship of neuromuscular dynamics with the sensed illness rating

AYKENT, Baris — Sun, 01 Jan 2012 00:00:00 GMT

A LQR washout algorithm for a driving simulator equipped with a hexapod platform : the relationship of neuromuscular dynamics with the sensed illness rating AYKENT, Baris; PAILLOT, Damien; KEMENY, Andras; MERIENNE, Frédéric This study proposes a method and an experimental validation to analyze dynamics response of the drivers with respect to the type of the control used in the hexapod driving simulator. In this article, two different forms of motion platform tracking control have been performed: - Classical motion cueing algorithm - LQR motion cueing algorithm For each situation, the EMG (electromyography) data have been registered from arm muscles of the drivers (flexor carpi radialis, brachioradialis). In addition, the acceleration based illness ratings (IR) have been computed. In order to process the data of the EMG and IR, the linear regression with a significance level of 0.05 has been assigned. Three cases have been evaluated: 1) Time exposure neuromuscular dynamics and vestibular–vehicle level conflict illness ratings 2) Time exposure neuromuscular dynamics and vestibular level sensed illness ratings 3) Impulse dynamics effect between the neuromuscular (EMG) and the vestibular dynamics (IR) The results have showed that: a) The vibration exposure condition: When the total RMS acceleration frequency weighted average IR increases, the EMG average total power increases too by driving the classical motion cueing algorithm. However, in contrast to this, the EMG average RMS total power decreases while the IR increases during the LQR motion cueing algorithm. b) Impulse effect condition: As the IR augments; the EMG average RMS total power also increases for the optimal motion cueing algorithm but it decreases for the classical algorithm.

Study of the Influence of Different Washout Algorithms on Simulator Sickness for a Driving Simulation Task

AYKENT, Baris — Sat, 01 Jan 2011 00:00:00 GMT

Study of the Influence of Different Washout Algorithms on Simulator Sickness for a Driving Simulation Task AYKENT, Baris; PAILLOT, Damien; FANG, Zhou; KEMENY, Andras; MERIENNE, Frédéric This paper deals with the effects of different washout algorithms used for Stewart platforms on subjective and objective ratings. Washout algorithms are used to represent vehicle dynamics in a restricted spatial place. An adaptive washout algorithm was realized to control the hexapod platform, depending on the specific force error in longitudinal, lateral and vertical directions, in order to compare user‟s experience with those in the case of classical algorithm. In this study, the simulator sickness has been evaluated for three algorithms in dynamic driving simulator situation in objective and subjective way.

Institut Image – Le2i

MARSH, William Eric — Thu, 01 Jan 2015 00:00:00 GMT

Institut Image – Le2i MARSH, William Eric; AYKENT, Baris; MARTINEZ, Jean-Luc; MERIENNE, Frédéric Institut Image is a department of Arts et Métiers ParisTech developing virtual reality (VR) for teaching, research, and innovation. The research team is composed of 30 people (teacher- researchers, engineers, PhD students) and is part of Le2i laboratory (CNRS lab). Institut Image hosts a master research program (15 students) and innovates through its technological platform PeTRiiV. Research activities are developed in strong relationship with industry. Several collaborative research programs are performed, including the VARI3 and Si2M projects presented briefly in this paper.

Effect of Closed-Loop Motion Cueing Algorithm for a Six-Degrees-of-Freedom Dynamic Simulator on Pupil Diameter as a Driver Stress Factor

AYKENT, Baris — Mon, 01 Jan 2018 00:00:00 GMT

Effect of Closed-Loop Motion Cueing Algorithm for a Six-Degrees-of-Freedom Dynamic Simulator on Pupil Diameter as a Driver Stress Factor AYKENT, Baris; PAILLOT, Damien; KEMENY, Andras; MERIENNE, Frédéric This paper describes the contribution of the closed-loop control of the motion platform (six degrees of freedom: longitudinal, lateral, and vertical displacements; pitch, roll, yaw) and motion platform’s three-dimensional (3D) displacement scale factor (SF) (0.2 and 1.0) on eye pupil diameter (PD) as an objective measure of driver cognitive load. Longitudinal, lateral, and vertical accelerations as well as longitudinal, lateral, and vertical positions from the center of gravity (CG) of the vehicle were registered through the driving simulation software SCANeRstudio® from OKTAL. Closed-loop control decreases the driver mental load. This type of closed-loop control can be used to decrease the driver mental load.

The Influence of the feedback control of the hexapod platform of the SAAM dynamic driving simulator on neuromuscular dynamics of the drivers

AYKENT, Baris — Sun, 01 Jan 2012 00:00:00 GMT

The Influence of the feedback control of the hexapod platform of the SAAM dynamic driving simulator on neuromuscular dynamics of the drivers AYKENT, Baris; PAILLOT, Damien; KEMENY, Andras; MERIENNE, Frédéric Multi sensorial cues (visual, auditory, haptic, inertial, vestibular, neuromuscular) [Ang2] play important roles to represent a proper sensation (objectively) and so a perception (subjectively as cognition) in driving simulators. Driving simulator aims at giving the sensation of driving as in a real case. For a similar situation, the driver has to react in the same way as in reality in terms of ‘self motion’. To enable this behavior, the driving simulator must enhance the virtual immersion of the subject in the driving situation. The subject has to perceive the motion of his own body in the virtual scene of the virtual car as he will have in a real car. For that reason, restituting the inertial cues on driving simulators is essential to acquire a more proper functioning [Kol20]. Simulation sickness has been one of the main research topics for the driving simulators. It was assessed between dynamic and static simulators [Cur7], [Wat32]). For a braking maneuver, [Sie29] stated that if the motion platform is activated the bias in reaching increased levels of decelerations was reduced strongly comparing to inactivated platform case. However, there has been lack in publications of vehicle-vestibular cue conflict based illness rating approach and its correlation with the neuromuscular dynamics for that kind of research. In order to reduce the simulator sickness, the difference between the accelerations through the visual and the vestibular cues have to be minimized (cost function minimization via model reference adaptive control, in this paper). Because of the fact that, this paper addresses the simulator motion sickness as a correlated function of this deviation for the both cues with the perception questionnaires as well as the EMG analysis results for the subjects who joined in those experiments. Due to the restricted workspace, it is not possible to represent the vehicle dynamics continuously with scale 1 to 1 on the motion platform [Moo22]. Nevertheless, the most desired aim is to minimize the deviation of the sensed accelerations between the represented dynamics as realistic as possible depending on the driving task. The perception of the driving is very difficult to evaluate in that context. This is the reason; the motion sickness is not easy to study as well. This research work has been performed under the dynamic operations of the SAAM driving simulator as an open-loop and a closed-loop controlled tracking of the hexapod platform of the SAAM dynamic driving simulator. It is obvious that inertial restitution addresses a significant role to maintain a developed fidelity of the driver behaviors on diving simulators The dynamic simulators are being used since the mid 1960s (Stewart platform) [Ste1] firstly for the flight simulators, then the use has spread to the automotive applications. The utilization scope diversifies from driver training to research purposes such as; vehicle dynamics control, advanced driving assistance systems (ADAS), motion and simulator sickness, etc. The dynamic driving simulator SAAM (Simulateur Automobile Arts et Métiers) involves a 6 DOF (degree of freedom) motion system. It acts around a RENAULT Twingo 2 cabin with the original control instruments (gas, brake pedals, steering wheel). The visual system is realized by an approximate 150° cylindrical view. Within the cabin for the employment of extensive measuring techniques (XSens motion tracker, and Biopac EMG (electromyography) device [Acq10]) prepared, which have been already used with numerous attempts such as sinus steer test, NATO chicane, etc. The visual accelerations of translations (longitudinal X, lateral Y and vertical Z axes) as well as the visual accelerations of roll and pitch, which correspond to the vehicle dynamics, were taken into account for the control. Then the platform positions, velocities and accelerations were controlled and fed back to minimize the conflict between the vehicle and the platform levels. The research question about this paper explains a comparative study between an open and a closed loop controlled platform in order to determine the spent power by the muscles to maintain the vehicle pursuing among the pylons. For the evaluation and the validation procedure [Kim19], [Wat32], [Rey27], [Kem17], [Che5], [Pic25], [Acq1], the scenario driven on the simulator SAAM with an open and a closed loop controlled platform to describe the impact of the feedback control. Some results from a case study will be illustrated in the scope of this research with real time controls of the platform at a longitudinal velocity of 60 km/h. The results of this study will be discussed also statistically to obtain the distribution of the dynamics behavior for a group of the participants. This research has been undertaken at ENSAM Institut Image, in collaboration with RENAULT.

Simulation sickness comparison between a limited field of view virtual reality head mounted display (Oculus) and a medium range field of view static ecological driving simulator (Eco2)

AYKENT, Baris — Wed, 01 Jan 2014 00:00:00 GMT

Simulation sickness comparison between a limited field of view virtual reality head mounted display (Oculus) and a medium range field of view static ecological driving simulator (Eco2) AYKENT, Baris; YANG, Zhao; KEMENY, Andras; MERIENNE, Frédéric In this article, an experimental procedure is presented in order to evaluate the role of having HMD oculus and (Eco2 driving simulator) in terms of driving simulation sickness. The driving simulation sickness is investigated with respect to SSQ (simulator sickness questionnaire) and vestibular dynamics (head movements) of the driver participants for a specific driving scenario. The scenario of driving task is created by using open source “iiVR (institut image virtual reality)” software which is developed by Institut Image Arts et Métiers ParisTech. The experiments are executed in static mode for the driving simulators.

Motion sickness evaluation and comparison for a static driving simulator and a dynamic driving simulator

AYKENT, Baris — Wed, 01 Jan 2014 00:00:00 GMT

Motion sickness evaluation and comparison for a static driving simulator and a dynamic driving simulator AYKENT, Baris; CHRISTOPHE, GUILLET; PAILLOT, Damien; KEMENY, Andras; MERIENNE, Frédéric This paper deals with driving simulation and in particular with the important issue of motion sickness. The paper proposes a methodology to evaluate the objective illness rating metrics deduced from the motion sickness dose value and questionnaires for both a static simulator and a dynamic simulator. Accelerations of the vestibular cues (head movements) of the subjects were recorded with and without motion platform activation. In order to compare user experiences in both cases, the head-dynamics-related illness ratings were computed from the obtained accelerations and the motion sickness dose values. For the subjective analysis, the principal component analysis method was used to determine the conflict between the subjective assessment in the static condition and that in the dynamic condition. The principal component analysis method used for the subjective evaluation showed a consistent difference between the answers given in the sickness questionnaire for the static platform case from those for the dynamic platform case. The two-tailed Mann–Whitney U test shows the significance in the differences between the self-reports to the individual questions. According to the two-tailed Mann–Whitney U test, experiencing nausea (p = 0.019 < 0.05) and dizziness (p = 0.018 < 0.05) decreased significantly from the static case to the dynamic case. Also, eye strain (p = 0.047 < 0.05) and tiredness (p = 0.047 < 0.05) were reduced significantly from the static case to the dynamic case. For the perception fidelity analysis, the Pearson correlation with a confidence interval of 95% was used to study the correlations of each question with the x illness rating component IRx, the y illness rating component IRy, the z illness rating component IRz and the compound illness rating IRtot. The results showed that the longitudinal head dynamics were the main element that induced discomfort for the static platform, whereas vertical head movements were the main factor to provoke discomfort for the dynamic platform case. Also, for the dynamic platform, lateral vestibular-level dynamics were the major element which caused a feeling of fear.