Note:

A tactile display system has been built with 25 contactors in a 5 × 5 array with 2mm spacing, designed to stimulate the fingertip. The drive mechanism for each contactor is a piezoelectric bimorph, allowing the display to use in functional magnetic resonance imaging experiments (fMRI). The amplitude and frequency of stimulation can be pre-set, and each contactor can be activated separately using a personal computer. The tactile produce a wide variety of time-varying spatial patterns of touch stimulation. The sensation is “natural” and the participants do not find the experience unpleasant. The psychophysics experiment and the first fMRI experiment involved identification of various patterns on the display: the tactile stimulus was stationary or moved in a circle or in a “random” trajectory with no obvious shape. Response was by push buttons. The second fMRI experiment focused on the relationship between the speed of tactile motion and the corresponding activation in the brain, using stimuli moving in a circular trajectory on the tactile display at various speeds in the range 2.9 to 77.9 mm s –1. In the psychophysics experiment, the mean identification score was 80% after only a few minutes’ practice. The results of the first fMRI experiment showed highly significant activations in primary and secondary somatosensory cortices for contrasts of circle or random stimuli with the rest condition; low significant activations in SI and SII were observed for the contrast of stationary stimuli with rest. Broca's area was found to be activated for circle and random stimulation but not for stationary stimulation. Results from the second fMRI experiment showed small speed-sensitive activations in the left side of the brain, mostly in the primary somatosensory cortex. The conclusion in present study was our tactile system can produce different types of tactile patterns and it works inside MRI scanner.

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"This thesis presents an effective approach to study tactile based mobile robot navigation. A Matlab simulator, which can simulate the properties of the tactile sensors, the environment, and the motion of the robot, is developed. The simulator uses an abstraction model of a compliant tactile sensor to represent an array of sensors covering the robot. The tactile sensor can detect normal and shear forces. The simulator has been used by a set of human subjects to drive a robot in an indoor environment to capture data. The details of the implementation and the data collected are presented in this thesis. From the data, some contact features can be extracted. Regarding the features, this thesis uses the Gaussian classifier and Gaussian mixture model to classify the data and build the feature classification model. Comparing the classification results of these two methods, the Gaussian mixture model has better performance. Applying the feature classification model, some contact objects can be detected, such as wall and corner. Based on this classification tool, a simple navigation problem can be solved successfully."

Thesis (Ph. D.)--Ohio State University, 2006. / Full text release at OhioLINK's ETD Center delayed at author's request

Multi-function interfaces have become increasingly pervasive and are frequently used in contexts which pose multiple demands on a single sensory modality. Assuming some degree of modularity in attentional processing and that using a different sensory channel for communication can reduce interference with critical visual tasks, one possibility is to divert some information through the touch sense. The goal of this Thesis is to advance our knowledge of relevant human capabilities and embed this knowledge into haptic communication design tools and procedures, in the interest of creating haptically supported interfaces that decrease rather than add to their users’ sensory and cognitive load. In short, we wanted to create tools and methods that would allow the creation of haptic signals (accomplished via display of either forces or vibrations) extending beyond the one bit of communication offered by current pagers and cellular phone buzzers. In our quest to create information-rich haptic signals we need to learn how to create signals that are differentiable. We also need to study ways to assign meanings to these signals and make sure that they can be perceived clearly when presented one after another even in environments where their recipient might be involved with other tasks. These needs frame the specific research goals of this thesis. Most of the results described here were obtained through the study of tactile (in the skin) rather than proprioceptive (force feedback) stimuli. We begin by presenting several methods to create, validate and contrast tactile stimulus dissimilarity data and investigate the design of a waveform intended to be a tactile perceptual intermediate between a square waveform and a triangle waveform. Next, we explore methods to create and test tactile signal-meaning associations and document a surprising ability of participants to exhibit high recall of quickly learned associations at two weeks in a first examination of longitudinal recall of tactile stimuli. We then present methods to measure tactile stimulus masking and identify crucial perceptual thresholds relating to stimulus temporal spacing in an exploration into the masking effects of common-onset vibrotactile stimuli. Finally, we present methods to test haptic and multimodal perception in simulated scenarios including a method to simulate and control cognitive workload; and provide evidence that the commonly-used device of multimodal signal reinforcement can adversely impact performance in an ongoing primary task. The research presented in this Thesis has implications for the design of signals to be used in displays that are emerging in embedded computing environments such as cars, games, cellular phones, and medical devices.

Intensive care IS a stressful environment and this thesis addresses the controversy as to whether tactile stimulation can mitigate the negative influences in ventilated preterms. There is an underlying assumption throughout the thesis that the pre term infant in intensive care experiences and is able to manifest physical and/or psychological pain. Preterms (n=75) were recruited with parental consent against strict entry criteria. A pre-test, post-test time series, counterbalanced design was used to evaluate the impact of an intervention to alleviate pain. The intervention [Touching and Caressing, Tender in Caring (T AC-TIC)] was compared with a control condition (spontaneous activity). Indicators of pain represented in the experiments were immunologic, physiological, and neurobehavioural. Data were analysed using parametric and non-parametric tests. The ontogeny of the secretory Immune system was investigated (n=70) using an enzyme-linked immunosorbant assay for Secretory Immunoglobulin A (SIgA). Ventilated preterms had significantly lower SIgA than infants requiring no mechanical ventilation. Breast milk fed preterms showed increased SIgA compared to other modes of nutrition. TACTIC increased SIgA in a subsample of ventilated preterms (n=35) with no changes following the control condition. Cardiovascular responses remained stable throughout T AC-TIC and spontaneous activity. No changes in gastric pH were observed in a sub-sample of 18 preterms. A neurobehavioural checklist was used to analyse videos for pain and comfort behaviours (n=29). Significantly more comfort behaviours were reported during T AC-TIC. Analysis of behavioural state indicated that more time was spent inactive sleep during than after TAC-TIC. No differences In state occurred between TAC-TIC and control condition. A ventilated subsample (n=25) of the original cohort was subjected to analysis at individual level for determination of congruence between simultaneously measured outcome variables. T AC-TIC produced increases more often in two or three variables. Pilot work has also been conducted addressing further controversies in tactile stimulation. The results are discussed within the theoretical frameworks of Gottlieb's hierarchical systems model, and Adamson-Macedo's Equilibrium model

Multi-function interfaces have become increasingly pervasive and are frequently used in contexts which pose multiple demands on a single sensory modality. Assuming some degree of modularity in attentional processing and that using a different sensory channel for communication can reduce interference with critical visual tasks, one possibility is to divert some information through the touch sense. The goal of this Thesis is to advance our knowledge of relevant human capabilities and embed this knowledge into haptic communication design tools and procedures, in the interest of creating haptically supported interfaces that decrease rather than add to their users’ sensory and cognitive load. In short, we wanted to create tools and methods that would allow the creation of haptic signals (accomplished via display of either forces or vibrations) extending beyond the one bit of communication offered by current pagers and cellular phone buzzers. In our quest to create information-rich haptic signals we need to learn how to create signals that are differentiable. We also need to study ways to assign meanings to these signals and make sure that they can be perceived clearly when presented one after another even in environments where their recipient might be involved with other tasks. These needs frame the specific research goals of this thesis. Most of the results described here were obtained through the study of tactile (in the skin) rather than proprioceptive (force feedback) stimuli. We begin by presenting several methods to create, validate and contrast tactile stimulus dissimilarity data and investigate the design of a waveform intended to be a tactile perceptual intermediate between a square waveform and a triangle waveform. Next, we explore methods to create and test tactile signal-meaning associations and document a surprising ability of participants to exhibit high recall of quickly learned associations at two weeks in a first examination of longitudinal recall of tactile stimuli. We then present methods to measure tactile stimulus masking and identify crucial perceptual thresholds relating to stimulus temporal spacing in an exploration into the masking effects of common-onset vibrotactile stimuli. Finally, we present methods to test haptic and multimodal perception in simulated scenarios including a method to simulate and control cognitive workload; and provide evidence that the commonly-used device of multimodal signal reinforcement can adversely impact performance in an ongoing primary task. The research presented in this Thesis has implications for the design of signals to be used in displays that are emerging in embedded computing environments such as cars, games, cellular phones, and medical devices.

No description available.