Driver Inattention During Vehicle Automation: How Does Driver Engagement Affect Resumption Of Control?

This driving simulator study, conducted as part of the EC-funded AdaptIVe project, investigated the effect of level of distraction during automation (Level 2 SAE) on drivers’ ability to assess automation uncertainty and react to a potential collision scenario. Drivers’ attention to the road was varied during automation in one of two driving screen manipulation conditions: occlusion by light fog and occlusion by heavy fog. Vehicle-based measures, drivers’ eye movements and response profiles to events after an automation uncertainty period were measured during a highly automated drive containing one of these manipulations, and compared to manual driving. In two of seven uncertainty events, a lead vehicle braked, causing a critical situation. Drivers' reactions to these critical events were compared in a between-subjects design, where the driving scene was manipulated for 1.5 minutes. Results showed that, during automation, drivers’ response profile to a potential collision scenario was less controlled and more aggressive immediately after the transition, compared to when they were in manual control. With respect to screen manipulation in particular, drivers in the heavy fog condition collided with the lead vehicle more often and also had a lower minimum headway compared to those in the light fog condition

Optic flow speed modulates guidance level control: New insights into two-level steering

© 2016 American Psychological Association. Responding to changes in the road ahead is essential for successful driving. Steering control can be modeled using 2 complementary mechanisms: guidance control (to anticipate future steering requirements) and compensatory control (to stabilize position-in-lane). Drivers seem to rapidly sample the visual information needed for steering using active gaze patterns, but the way in which this perceptual information is combined remains unclear. Influential models of steering capture many steering behaviors using just 'far' and 'near' road regions to inform guidance and compensatory control respectively (Salvucci & Gray, 2004). However, optic flow can influence steering even when road-edges are visible (Kountouriotis, Mole, Merat, & Wilkie, 2016). Two experiments assessed whether flow selectively interacted with compensatory and/or guidance levels of steering control, under either unconstrained gaze or constrained gaze conditions. Optic flow speed was manipulated independent of the veridical roadedges so that use of flow would lead to predictable understeering or oversteering. Steering was found to systematically vary according to flow speed, but crucially the Flow-Induced Steering Bias (FISB) magnitude depended on which road-edge components were visible. The presence of a guidance signal increased the influence of flow, with the largest FISB in 'Far' and 'Complete' road conditions, whereas the smallest FISB was observed when only 'Near' road-edges were visible. Gaze behaviors influenced steering to some degree, but did not fully explain the interaction between flow and road-edges. Overall the experiments demonstrate that optic flow can act indirectly upon steering control by modulating the guidance signal provided by a demarcated path

The role of gaze and road edge information during high speed locomotion.

Robust control of skilled actions requires the flexible combination of multiple sources of information. Here we examined the role of gaze during high-speed locomotor steering and in particular the role of feedback from the visible road edges. Participants were required to maintain one of three lateral positions on the road when one or both edges were degraded (either by fading or removing them). Steering became increasingly impaired as road edge information was degraded, with gaze being predominantly directed towards the required road position. When either of the road edges were removed, we observed systematic shifts in steering and gaze direction dependent upon both the required road position and the visible edge. A second experiment required fixation on the road center or beyond the road edges. The results showed that the direction of gaze led to predictable steering biases, which increased as road edge information became degraded. A new steering model demonstrates that the direction of gaze and both road edges influence steering in a manner consistent with the flexible weighted combination of near road feedback information and prospective gaze information

The influence of visual flow and perceptual load on locomotion speed

Visual flow is used to perceive and regulate movement speed during locomotion. We assessed the extent to which variation in flow from the ground plane, arising from static visual textures, influences locomotion speed under conditions of concurrent perceptual load. In two experiments, participants walked over a 12-m projected walkway that consisted of stripes that were oriented orthogonal to the walking direction. In the critical conditions, the frequency of the stripes increased or decreased. We observed small, but consistent effects on walking speed, so that participants were walking slower when the frequency increased compared to when the frequency decreased. This basic effect suggests that participants interpreted the change in visual flow in these conditions as at least partly due to a change in their own movement speed, and counteracted such a change by speeding up or slowing down. Critically, these effects were magnified under conditions of low perceptual load and a locus of attention near the ground plane. Our findings suggest that the contribution of vision in the control of ongoing locomotion is relatively fluid and dependent on ongoing perceptual (and perhaps more generally cognitive) task demands

Robot Guided ‘Pen Skill’ Training in Children with Motor Difficulties

Motor deficits are linked to a range of negative physical, social and academic consequences. Haptic robotic interventions, based on the principles of sensorimotor learning, have been shown previously to help children with motor problems learn new movements. We therefore examined whether the training benefits of a robotic system would generalise to a standardised test of ‘pen-skills’, assessed using objective kinematic measures [via the Clinical Kinematic Assessment Tool, CKAT]. A counterbalanced, cross-over design was used in a group of 51 children (37 male, aged 5-11 years) with manual control difficulties. Improved performance on a novel task using the robotic device could be attributed to the intervention but there was no evidence of generalisation to any of the CKAT tasks. The robotic system appears to have the potential to support motor learning, with the technology affording numerous advantages. However, the training regime may need to target particular manual skills (e.g. letter formation) in order to obtain clinically significant improvements in specific skills such as handwriting

Numerical investigation of VOC levels in the area of petrol stations

In the area of petrol stations several Volatile Organic Compounds (VOCs) leak into the atmosphere due to the evaporation of liquid fuels, especially of gasoline that is predominantly composed of light hydrocarbons. The aim of the present study is to investigate the spatial distribution of various VOCs when leaked into the atmosphere in the area of a petrol station. The study is based on numerical simulations. The effect of wind speed and direction, as well as of air temperature has been studied. Gasoline components of different properties have been studied (e.g. pentane, iso-octane, o-xylene, toluene, benzene), as well as ethanol that is considered a new fuel blend component that can be found in different fractions in new gasoline blends worldwide. The area of flammable cloud near the source of the leak is investigated for various atmospheric conditions taking into account the lower and higher flammable limits of each compound. Lastly, the exposure to gasoline vapour is studied taking into consideration the recommended occupational exposure limits of various organisations

Performance on the Detection Response Task during driving: Separating the manual and cognitive element of the secondary task

The Detection Response Task (DRT) is designed to measure driver distraction from secondary tasks. This driving simulator study compared drivers’ performance on the head mounted version of the DRT during dual task conditions (DRT + driving) with performance in a tertiary task setting (DRT + driving + secondary task). Three secondary tasks were used, requiring: nonvisual, visual, or visuomanual resources. The 1-back (Easy) and countback in 7s (Difficult) tasks were used as two levels of a nonvisual task. For the visual and visuomanual task, a visual search display was presented on the simulator screen, which overlapped with the back of a lead car. Response to this task was either verbal (visual) or via buttons on the steering wheel (visuomanual). Results showed DRT to be sensitive to the different difficulty levels of the nonvisual task. DRT performance did not distinguish between different perceptual demands of the visual task, but was affected by the manual load of the visuomanual task. Understanding the role of task pace in these studies is thought to be an important factor and further work using different visual tasks is also required to appreciate the value of the DRT in evaluating the distracting effects of in-vehicle HMI

Study of the stell/slag interface instability and the influence of injected gas in the continuous casting of steel

Main objective of this work is the development of a time-dependent Finite Volume (FV) numerical model to analyse the hydrodynamic behaviour of the steel/slag interface in the Continuous Casting (CC) of steel. The Eulerian representation of the flowfield in the mould region, driven by the Submerged Entry Nozzle (SEN) jets supplying the steel, is accompanied by a Lagrangian representation of gas bubble tracks. Coupling of the gas and liquid fields modifies the flow and consequently interface stability. Due to the cost and risk involved in actual casting measurements, the numerical model has been validated against water-model experiments, using Laser Doppler Anemometry (LDA) technology to obtain time-dependent velocity data and video to capture the interface dynamics. In the experiment, silicon oil mimics the protective slag layer; water the liquid steel and air injected through the SEN imitates the argon gas used in an actual caster. LDA measurements - taken over 600s real time - identify low frequency oscillations in the flow. To uncover the source of these oscillations and reproduce the same information in the model, long transient 3D simulations are necessary. Standard Volume of Fluid (VOF) techniques (Donor-Acceptor, Van Leer, Level-Set-Methods) are normally used to analyse interface motion. However, since these are in general explicit, very small time steps are needed, leading to extremely long computations. In this study, interface motion is modelled using an implicit Counter Diffusion Method (CDM) formulation (Pericleous et al. 2008) reducing computational time by an order of magnitude. Qualitative comparison of the results against water model visualizations explains several observed phenomena and highlights the effects of different process parameters (casting speed, gas flowrate, oil layer thickness). Quantitative comparison is against LDA data for the mean value and standard deviation of the horizontal velocity component and its frequency spectrum. The study suggests that the observed frequencies are related to the turnover time of the two main recirculation loops that appear in the CC mould following the collision of the SEN jets and the narrow faces of the mould. With the inclusion of heat transfer and solidification, the numerical model addresses the full three-phase problem of a real caster. In particular, the model investigates the influence of argon buoyancy on the steel flow pattern in an industrial configuration. The predicted results compare favourably with available measurements, where the flowfield shows a change in the overall steel velocity pattern from a single roll to a double roll as the relative amount of gas increases. The model in addition predicts the solidified skin thickness and heat distribution across the slag layer as a function of casting parameters

Experimental and numerical investigation of the transient meniscus behaviour in a continuous caster

This is a project to develop a dynamic CFD model of the continuous caster mould region with the aid of an experimental water-model configuration. The emphasis will be on hydrodynamic aspects of the slag/steel interface behaviour and in particular the effects of injected gas bubbles on interface stability. The model includes an improved implicit Counter Diffusion Method (CDM) interface-tracking scheme for numerical efficiency and a Lagrangian representation of argon bubble tracks. In the water model, an oil layer is used to represent the slag. Qualitative evaluation of the results against water model visualizations explains the main flow patterns observed, and validates the predicted deformation of the meniscus. Quantitative comparison against LDA velocity measurements is provided at seven measurement positions and the nature of observed wave action is analyzed by its spectral pattern. The dominant frequencies measured are correlated against the turnover time of the top and bottom recirculation regions in the caster for various SEN casting velocities and gas flow rates. The effect of gas is seen to have an important influence on the flowfield in general, but also on interface behaviour and on the frequencies observed. This influence is also seen in the case of a real industrial continuous caster, where velocity measurements and simulations show a change in the steel velocity pattern from a “single roll” to a “double roll” as the relative amount of gas increases