This study investigated automobile drivers' ability to localize auditory and haptic (touch) alarms in terms of speed and accuracy. Thirty-two subjects, balanced across age (20-30 years old and 60-70 years old) and gender, participated in the study. Subjects were screened for minimum hearing of 40 dB for 500 Hz through 4000 Hz auditory tones, and maximum bilateral hearing differences of 10 dB. The experiment consisted of subjects identifying the target location of an alarm while driving a 2001 Buick LeSabre at 55 mph in light traffic. Four alarm modes were tested: 1) an auditory broadband alarm, 2) a haptic seat, 3) a combination of the haptic and the auditory alarm modes, and 4) a combination of the haptic alarm mode with a non-directional auditory alarm played from the front speakers of the vehicle. The alarms were evoked from eight target locations: the front-left, front, front-right, right, back-right, back, back-left, and left. The target locations of the auditory alarm mode existed around the interior of the car cabin using the vehicle's stock sound system speakers. The haptic alarm target locations existed in the bottom of the driver seat using an eight-by-eight grid of actuators. The experimenter evoked the alarms while subjects drove along a two-lane highway, and the alarms were not associated with any actual collision threat. Subjects were instructed to quickly identify the location of the alarm by calling them out, while being as correct as possible. Their choice response time and target location selection was recorded. The alarms were presented approximately every minute during fifteen-minute intervals over the duration of two and a half hours. Subjects completed questionnaires regarding their preference to the alarm modes. Under the conditions investigated, subjects localized the haptic alarm mode faster and more accurately than the auditory alarm mode. Subjects performed equally well with the haptic alarm mode and the two auditory and haptic combination alarm modes in terms of speed and accuracy in identifying their location. Subjects did express a preference for the addition of the auditory component to the haptic alarm mode, perhaps owing to a heightened sense of urgency. However, subjects preferred the haptic alarm mode on its own in response to hypothetical false alarm questions, perhaps because it was less annoying. Alarm mode discriminability was believed to affect localization accuracy and response time owing to its effect on the likelihood of correctly identifying a target location and the attention resources required to differentiate adjacent target locations. / Master of Science

abstract: The world’s population is currently 9% visually impaired. Medical sciences do not have a biological fix that can cure this visual impairment. Visually impaired people are currently being assisted with biological fixes or assistive devices. The current assistive devices are limited in size as well as resolution. This thesis presents the development and experimental validation of a control system for a new vibrotactile haptic display that is currently in development. In order to allow the vibrotactile haptic display to be used to represent motion, the control system must be able to change the image displayed at a rate of at least 30 frames/second. In order to achieve this, this thesis introduces and investigates the use of three improvements: threading, change filtering, and wave libraries. Through these methods, it is determined that an average of 40 frames/second can be achieved. / Dissertation/Thesis / Masters Thesis Engineering 2018

abstract: One type of assistive device for the blind has attempted to convert visual information into information that can be perceived through another sense, such as touch or hearing. A vibrotactile haptic display assistive device consists of an array of vibrating elements placed against the skin, allowing the blind individual to receive visual information through touch. However, these approaches have two significant technical challenges: large vibration element size and the number of microcontroller pins required for vibration control, both causing excessively low resolution of the device. Here, I propose and investigate a type of high-resolution vibrotactile haptic display which overcomes these challenges by utilizing a ‘microbeam’ as the vibrating element. These microbeams can then be actuated using only one microcontroller pin connected to a speaker or surface transducer. This approach could solve the low-resolution problem currently present in all haptic displays. In this paper, the results of an investigation into the manufacturability of such a device, simulation of the vibrational characteristics, and prototyping and experimental validation of the device concept are presented. The possible reasons of the frequency shift between the result of the forced or free response of beams and the frequency calculated based on a lumped mass approximation are investigated. It is found that one of the important reasons for the frequency shift is the size effect, the dependency of the elastic modulus on the size and kind of material. This size effect on A2 tool steel for Micro-Meso scale cantilever beams for the proposed system is investigated. / Dissertation/Thesis / Doctoral Dissertation Systems Engineering 2019

This thesis research is concerned with the exploration, design, and validation of novel haptic technologies and signals that feel natural and meaningful in a calm and pleasant way. Our ultimate goal is to expand the possibilities of human-machine interaction by developing a single tactile display and a set of signals through a systematic design approach. It is generally a challenge to evoke a broad range of emotions with vibrotactile stimulation, especially at low signal intensities. During the first part of this thesis research, three types of prototypes were developed and explored using novel haptic technologies. The first was a circular array braille display consisting of eight small six-pin braille modules. The forty-eight pins were arranged in a circular shape to deliver circular tactile information such as time and direction. The second was a braille stick consisting of sixteen six-pin braille modules arranged in a row. The entire display could be easily grasped in the hand so that tactile information can be easily accessible. The third was a 3-by-3 electroactive polymer actuator array driven at high voltages that gives a subtle “tapping” feel on the skin. However, each of the three prototypes suffered from a limited range of expression and was not pursued further.<br> After the initial prototyping efforts, a 2-by-2 vibrotactile display, the palmScape, was conceived and developed. Custom-designed stimulation patterns based on natural phenomena that feel calm and pleasant were designed and implemented with the palmScape. We use text labels to set the context for the vibrotactile icons that attempt to capture and expresses natural metaphors through variations in signal amplitude, frequency, duration, rhythm, modulation, spatial extent, as well as slow movements. Fourteen participants evaluated twenty vibrotactile icons by rating the perceived valence and arousal levels. The twenty stimuli included sixteen custom-designed vibrotactile icons from this thesis research and four reference patterns from two published studies. The results show that our custom-designed patterns were rated at higher valence levels than the corresponding reference signals at similar arousal ratings. Five of the sixteen vibrotactile icons from this research occupied the fourth quadrant of the valence-arousal space that corresponds to calm and pleasant signals. These findings support the validity of the palmScape display and our signal design approach for achieving a calm and pleasant experience and the possibility of reaching a broader range of expressiveness with vibrotactile signals.<br> Future studies will continue with the design of signals that can express a broader range of metaphors and emotions through the palmScape, and build an emotional evaluation database that can be combined with other modalities. Our work can be further expanded to support an immersive experience with naturalistic-feeling vibrotactile effects and broaden the expressiveness of human-computer interfaces in media consumption, gaming, and other communicative application domains.