Haptic foot pedal : influence of shoe type, age, and gender on subjective pulse perception

This study investigates the influence of shoe type (sneakers and safety boots), age, and gender on the perception of haptic pulse feedback provided by a prototype accelerator pedal in a running stationary vehicle. Haptic feedback can be a less distracting alternative to traditionally visual and auditory in-vehicle feedback. However, to be effective, the device delivering the haptic feedback needs to be in contact with the person. Factors such as shoe type vary naturally over the season and could render feedback that is perceived well in one situation, unnoticeable in another. In this study, we evaluate factors that can influence the subjective perception of haptic feedback in a stationary but running car: shoe type, age, and gender. Thirty-six drivers within three age groups (≤39, 40-59, and ≥60) took part. For each haptic feedback, participants rated intensity, urgency, and comfort via a questionnaire. The perception of the haptic feedback is significantly influenced by the interaction between the pulse's duration and force amplitude and the participant's age and gender but not shoe type. The results indicate that it is important to consider different age groups and gender in the evaluation of haptic feedback. Future research might also look into approaches to adapt haptic feedback to the individual driver's preferences. Findings from this study can be applied to the design of an accelerator pedal in a car, for example, for a nonvisual in-vehicle warning, but also to plan user studies with a haptic pedal in general

A review of human sensory dynamics for application to models of driver steering and speed control.

In comparison with the high level of knowledge about vehicle dynamics which exists nowadays, the role of the driver in the driver-vehicle system is still relatively poorly understood. A large variety of driver models exist for various applications; however, few of them take account of the driver's sensory dynamics, and those that do are limited in their scope and accuracy. A review of the literature has been carried out to consolidate information from previous studies which may be useful when incorporating human sensory systems into the design of a driver model. This includes information on sensory dynamics, delays, thresholds and integration of multiple sensory stimuli. This review should provide a basis for further study into sensory perception during driving.This work was supported by the UK Engineering and Physical Sciences Research Council (EP/P505445/1) (studentship for Nash).This is the published version. It first appeared from Springer at http://dx.doi.org/10.1007/s00422-016-0682-x

New knowledge and methods for mitigating driver distraction

Driver distraction is the diversion of attention to a non-driving related activity. It has been identified as major cause of accidents. Even as we move away from traditional ‘driver’ and towards highly-automated vehicles, distraction remains an important issue. A distracted driver could still potentially miss a handover of control message from the car, or have a reduced awareness of the traffic environment. With the increased number and complexity of new features being introduced in vehicles, it is becoming more important to understand how drivers interact with them, to understand the benefit they offer in helping the driver to focus on-road, but also to identify their limitations and risks. Thereby it is important to consider that the interaction between human and technology, e.g. driver distraction, can be described by many aspects. To learn the most about the interaction between user and technology, it is important to select a suitable measure and to utilise that measure in best practice, which can be hard to find in literature. This research project is divided into two research streams that investigate the opportunities of new in-vehicle interfaces to mitigate driver distraction and that research how to efficiently identify measures for the ergonomic evaluation of in-vehicle interfaces. Research stream one, comprising four studies, evaluated tactile information as a new interface technology to mitigate distraction in manual and automated cars. Tactile perception requires physical contact between the driver and the device delivering the feedback. It can be decreased by clothing. In the first user trial it was evaluated, for the first time, how shoe type, gender, and age influence the driver’s perception of a tactile pedal. Shoe type did not, but gender, age, and the feedback’s duration and amplitude did influence the perception. In some durations and amplitudes, the feedback was recognised by all participants and was rated highly intense, both aspects a warning should have. Next, it was evaluated how fast people would react to a tactile warning compared to a traditional auditory warning and an auditory-tactile warning. The participants reacted significantly slower to the tactile warning. Following, a tactile warning might not be suitable as an in-vehicle warning. However, adding an auditory component to the tactile warning increases its efficiency and people missed less auditory-tactile compared to auditory warnings. Newly introduced interfaces, such as tactile interfaces, put an effort on drivers to adjust to them and might lead to unsafe interactions. In the third and fourth study, it was investigated how a driver’s trust effects the reaction time and glance behaviour. Trust was not associated with the reaction time towards a tactile warning signal, but it influenced the glances at a voice-navigation interface that was new for the majority of the participants. The findings can be utilised to increase the trust in the interface dialogue and thereby decrease a driver’s time glanced off-road. Research stream two investigated how Human-Machine-Interface (HMI) engineers can be supported in the comparison and selection of measures (e.g. a usability score) to evaluate the ergonomics of in-vehicle devices, for example to measure driver distraction. Industry projects are often restricted by tight deadlines and limited availability of equipment. Measure selection can then become a time critical issue. In published literature, there existed no guidelines to support this task. In four rapid prototyping evaluations, an interface was developed that can aid HMI-engineers in the comparison and selection of measures for an ergonomic evaluation. The tool functions as knowledge management and foresees to inform users about the best practice to utilise a measure, tips to set-up required equipment, and templates for the measure, for example templates for the analysis or electronic versions of questionnaires

Motion cueing in driving simulators for research applications

This research investigated the perception of self-motion in driving simulation, focussing on the dynamic cues produced by a motion platform. The study was undertaken in three stages, evaluating various motion cueing techniques based on both subjective ratings of realism and objective measures of driver performance. Using a Just Noticeable Difference methodology, Stage 1 determined the maximum perceptible motion scaling for platform movement in both translation and tilt. Motion cues scaled by 90% or more could not be perceptibly differentiated from unscaled motion. This result was used in Stage 2‟s examination of the most appropriate point in space at which the platform translations and rotations should be centred (Motion Reference Point, MRP). Participants undertook two tracking tasks requiring both longitudinal (braking) and lateral (steering) vehicle control. Whilst drivers appeared unable to perceive a change in MRP from head level to a point 1.1m lower, the higher position (closer to the vestibular organs) did result in marginally smoother braking, corresponding to the given requirements of the longitudinal driving task. Stage 3 explored the perceptual trade-off between the specific force error and tilt rate error generated by the platform. Three independent experimental factors were manipulated: motion scale-factor, platform tilt rate and additional platform displacement afforded by a XY-table. For the longitudinal task, slow tilt that remained sub-threshold was perceived as the most realistic, especially when supplemented by the extra surge of the XY-table. However, braking task performance was superior when a more rapid tilt was experienced. For the lateral task, perceived realism was enhanced when motion cues were scaled by 50%, particularly with added XY-sway. This preference was also supported by improvements in task accuracy. Participants ratings were unmoved by changing tilt rate, although rapid tilt did result in more precise lane control. Several interactions were also observed, most notably between platform tilt rate and XY-table availability. When the XY-table was operational, driving task performance varied little between sub-threshold and more rapid tilt. However, while the XY-table was inactive, both driving tasks were better achieved in conditions of high tilt rate. An interpretation of these results suggests that without the benefit of significant extra translational capability, priority should be given to the minimisation of specific force error through motion cues presented at a perceptibly high tilt rate. However, XY-table availability affords the simulator engineer the luxury of attaining a slower tilt that provides both accurate driving task performance and accomplishes maximum perceived realism

Reaching Performance in Heathy Individuals and Stroke Survivors Improves after Practice with Vibrotactile State Feedback

Stroke causes deficits of cognition, motor, and/or somatosensory functions. These deficits degrade the capability to perform activities of daily living (ADLs). Many research investigations have focused on mitigating the motor deficits of stroke through motor rehabilitation. However, somatosensory deficits are common and may contribute importantly to impairments in the control of functional arm movement. This dissertation advances the goal of promoting functional motor recovery after stroke by investigating the use of a vibrotactile feedback (VTF) body-machine interface (BMI). The VTF BMI is intended to improve control of the contralesional arm of stroke survivors by delivering supplemental limb-state feedback to the ipsilesional arm, where somatosensory feedback remains intact. To develop and utilize a VTF BMI, we first investigated how vibrotactile stimuli delivered on the arm are perceived and discriminated. We determined that stimuli are better perceived sequentially than those delivered simultaneously. Such stimuli can propagate up to 8 cm from the delivery site, so future applications should consider adequate spacing between stimulation sites. We applied these findings to create a multi-channel VTF interface to guide the arm in the absence of vision. In healthy people, we found that short-term practice, less than 2.5 hrs, allows for small improvements in the accuracy of horizontal planar reaching. Long-term practice, about 10 hrs, engages motor learning such that the accuracy and efficiency of reaching is improved and cognitive loading of VTF-guided reaching is reduced. During practice, participants adopted a movement strategy whereby BMI feedback changed in just one channel at a time. From this observation, we sought to develop a practice paradigm that might improve stroke survivors’ learning of VTF-guided reaching without vision. We investigated the effects of practice methods (whole practice vs part practice) in stroke survivors’ capability to make VTF-guided arm movements. Stroke survivors were able to improve the accuracy of VTF-guided reaching with practice, however there was no inherent differences between practice methods. In conclusion, practice on VTF-guided 2D reaching can be used by healthy people and stroke survivors. Future studies should investigate long-term practice in stroke survivors and their capability to use VTF BMIs to improve performance of unconstrained actions, including ADLs

Visual Perception and Cognition in Image-Guided Intervention

Surgical image visualization and interaction systems can dramatically affect the efficacy and efficiency of surgical training, planning, and interventions. This is even more profound in the case of minimally-invasive surgery where restricted access to the operative field in conjunction with limited field of view necessitate a visualization medium to provide patient-specific information at any given moment. Unfortunately, little research has been devoted to studying human factors associated with medical image displays and the need for a robust, intuitive visualization and interaction interfaces has remained largely unfulfilled to this day. Failure to engineer efficient medical solutions and design intuitive visualization interfaces is argued to be one of the major barriers to the meaningful transfer of innovative technology to the operating room. This thesis was, therefore, motivated by the need to study various cognitive and perceptual aspects of human factors in surgical image visualization systems, to increase the efficiency and effectiveness of medical interfaces, and ultimately to improve patient outcomes. To this end, we chose four different minimally-invasive interventions in the realm of surgical training, planning, training for planning, and navigation: The first chapter involves the use of stereoendoscopes to reduce morbidity in endoscopic third ventriculostomy. The results of this study suggest that, compared with conventional endoscopes, the detection of the basilar artery on the surface of the third ventricle can be facilitated with the use of stereoendoscopes, increasing the safety of targeting in third ventriculostomy procedures. In the second chapter, a contour enhancement technique is described to improve preoperative planning of arteriovenous malformation interventions. The proposed method, particularly when combined with stereopsis, is shown to increase the speed and accuracy of understanding the spatial relationship between vascular structures. In the third chapter, an augmented-reality system is proposed to facilitate the training of planning brain tumour resection. The results of our user study indicate that the proposed system improves subjects\u27 performance, particularly novices\u27, in formulating the optimal point of entry and surgical path independent of the sensorimotor tasks performed. In the last chapter, the role of fully-immersive simulation environments on the surgeons\u27 non-technical skills to perform vertebroplasty procedure is investigated. Our results suggest that while training surgeons may increase their technical skills, the introduction of crisis scenarios significantly disturbs the performance, emphasizing the need of realistic simulation environments as part of training curriculum

Proceedings of the Human Factors and Ergonomics Society Europe Chapter 2014 Annual Conference:Human Factors in high reliability industries

On the occasion of the 2014 Meeting in Lisbon, Portuga

Proceedings of the Human Factors and Ergonomics Society Europe Chapter 2014 Annual Conference:Human Factors in high reliability industries

On the occasion of the 2014 Meeting in Lisbon, Portuga