A tactile communication system for navigation

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (leaves 42-43).A vibrotactile display for use in navigation has been designed and evaluated. The arm and the torso, which offer relatively large and flat surface areas, were chosen as locations for the displays. The ability of subjects to identify patterns of vibrotactile stimulation on the arm and torso was tested in a series of experiments using the vibrotactile displays. A variety of patterns of stimulation was evaluated to determine which was most effective, and the efficacy of two types of motors (pancake and cylindrical) was compared. The arm display was tested with sedentary subjects in the laboratory, and the torso display was tested both in the laboratory with sedentary subjects and outdoors with active subjects. The results indicated that identification of the vibrotactile patterns was superior on the torso as compared to the forearm, with subjects achieving 99-100% accuracy with seven of the eight patterns presented. The torso display was equally effective for both sedentary and active subjects.by Erin M. Piateski.S.M

A Vibrotactile Display Design, evaluation and Fabrication

Vision and audition are the two best understood modalities which humans use to interact with the outside world. These modalities can provide highly precise spatial and temporal information. Thus, the field of human-computer interface design has focused much of their study and design on these modalities. On the other hand, the sense of touch has been largely ignored despite the fact that it is an essential part of human ability to interact with the environment. We are interested to identify key findings on how to use tactile technology effectively to design and fabricate a tactile interface. We intend to design a wearable tactile interface which can assist Unmanned Aerial Vehicles (UAV) operators in supervisory control and monitoring tasks. Tactile displays are usually comprised of vibratory stimulators which are arranged in specific formation based on the application of the display. Quantitative properties of a vibrating tactor which was used as the vibratory stimulator in our tactile interface were investigated and evaluated in this study. We executed a series of experiments to investigate the intensity of vibrations that the vibrating tactor can generate when it is being activated through different electrical signals. Driving signals were different in terms of waveform, frequency and amplitude. By applying the outcomes of our experiments, and using the available guidelines for the design of tactile displays, we proposed some methods for displaying flight dynamics (Roll, Pitch and Yaw) of a UAV through a tactile display which is structured in form of a vest. Due to the relative infancy of this branch of information presentation, and also the lack of thorough discussion within the scientific community we need to execute further experiments to evaluate the performance of the suggested tactile display

Effectiveness of Vibration-based Haptic Feedback Effects for 3D Object Manipulation

This research explores the development of vibration-based haptic feedback for a mouse-like computer input device. The haptic feedback is intended to be used in 3D virtual environments to provide users of the environment with information that is difficult to convey visually, such as collisions between objects. Previous research into vibrotactile haptic feedback can generally be split into two broad categories: single tactor handheld devices; and multiple tactor devices that are attached to the body. This research details the development of a vibrotactile feedback device that merges the two categories, creating a handheld device with multiple tactors. Building on previous research, a prototype device was developed. The device consisted of a semi-sphere with a radius of 34 mm, mounted on a PVC disk with a radius of 34 mm and a height of 18 mm. Four tactors were placed equidistantly about the equator of the PVC disk. Unfortunately, vibrations from a single tactor caused the entire device to shake due to the rigid plastic housing for the tactors. This made it difficult to accurately detect which tactor was vibrating. A second prototype was therefore developed with tactors attached to elastic bands. When a tactor vibrates, the elastic bands dampen the vibration, reducing the vibration in the rest of the device. The goal of the second prototype was to increase the accuracy in localizing the vibrating tactor. An experiment was performed to compare the two devices. The study participants grasped one of the device prototypes as they would hold a computer mouse. During each trial, a random tactor would vibrate. By pushing a key on the keyboard, the participants indicated when they detected vibration. They then pushed another key to indicate which tactor had been vibrating. The procedure was then repeated for the other device. Detection of the vibration was faster (p < 0.01) and more accurate (p < 0.001) with the soft shell design than with the hard shell design. In a post-experiment questionnaire, participants preferred the soft shell design to the hard shell design. Based on the results of the experiment, a mould was created for building future prototypes. The mould allows for the rapid creation of devices from silicone. Silicone was chosen as a material because it can easily be moulded and is available in different levels of hardness. The hardness of the silicone can be used to control the amount of damping of the vibrations. To increase the vibration damping, a softer silicone can be used. Several recommendations for future prototypes and experiments are made

‘Subtle’ Technology: Design for Facilitating Face-to-Face Interaction for Socially Anxious People

PhD thesisShy people have a desire for social interaction but fear being scrutinised and rejected. This conflict results in attention deficits during face-to-face situations. It can cause the social atmosphere to become ‘frozen’ and shy persons to appear reticent. Many of them avoid such challenges, taking up the ‘electronic extroversion’ route and experiencing real-world social isolation. This research is aimed at improving the social skills and experience of shy people. It establishes conceptual frameworks and guidelines for designing computer-mediated tools to amplify shy users’ social cognition while extending conversational resources. Drawing on the theories of Social Objects, ‘natural’ HCI and unobtrusive Ubiquitous Computing, it proposes the Icebreaker Cognitive-Behavioural Model for applying user psychology to the systems’ features and functioning behaviour. Two initial design approaches were developed in forms of Wearable Computer and evaluated in a separate user-centred study. One emphasised the users’ privacy concerns in the form of a direct but covert display of the Vibrosign Armband. Another focused on low-attention demand and low-key interaction preferences – rendered through a peripheral but overt visual display of the Icebreaker T-shirt, triggered by the users’ handshake and disguised in the system’s subtle operation. Quantitative feedback by vibrotactile experts indicated the armband effective in signalling various types of abstract information. However, it added to the mental load and needed a disproportionate of training time. In contrast, qualitative-based feedback from shy users revealed unexpected benefits of the information display made public on the shirt front. It encouraged immediate and fluid interaction by providing a mutual ‘ticket to talk’ and an interpretative gap in the users’ relationship, although the rapid prototype compromised the technology’s subtle characteristics and impeded the users’ social experience. An iterative design extended the Icebreaker approach through a systematic refinement and resulted in the Subtle Design Principle implemented in the Icebreaker Jacket. Its subtle interaction and display modalities were compared to those of a focal-demand social aid, using a mixed-method evaluation. Inferential analysis results indicated the subtle technology more engaging with users’ social aspirations and facilitating a higher degree of unobtrusive experience. Through the Icebreaker model and Subtle Design Principle, together with the exploratory research framework and study outcome, this thesis demonstrates the advantages of using subtle technology to help shy users cope with the challenges of face-to-face interaction and improve their social experience.RCUK under the Digital Economy Doctoral Training scheme, through MAT programme, EPSRC Doctoral Training Centre EP/G03723X/1

Tactile and Crossmodal Change Blindness and its Implications for Display Design.

Data overload, especially in the visual channel, and associated breakdowns in monitoring already represent a major challenge in data-rich environments. One promising means of overcoming data overload is through the introduction of multimodal displays, i.e., displays which distribute information across various sensory channels (including vision, audition, and touch). This approach has been shown to be effective in offloading the overburdened visual channel and thus reduce data overload. However, the effectiveness of these displays may be compromised if their design does not take into consideration limitations of human perception and cognition. One important question is the extent to which the tactile modality is susceptible to change blindness. Change blindness refers to the failure to detect even large and expected changes when these changes coincide with a “transient” stimulus. To date, the phenomenon has been studied primarily in vision, but there is limited empirical evidence that the tactile modality may also be subject to change blindness. If confirmed, this raises concerns about the robustness of multimodal displays and their use. A series of research activities described in this dissertation sought to answer the following questions: (1) to what extent, and under what circumstances, is the sense of touch susceptible to change blindness, (2) does change blindness occur crossmodally between vision and touch, and (3) how effective are three different display types for overcoming these phenomena. The effect of transient type, transient duration, and task demands were also investigated in the context of Unmanned Aerial Vehicle (UAV) control, the selected domain of application. The findings confirmed the occurrence of intramodal tactile change blindness, but not crossmodal change blindness. Subsequently, three countermeasures to intramodal tactile change blindness were developed and evaluated. The design of these countermeasures focused on supporting four of the five steps required for change detection and was found to significantly improve performance compared to when there was no countermeasure in place. Overall, this research adds to the knowledge base in multimodal and redundant information processing and can inform the design of multimodal displays not only for UAV control, but also other complex, data-rich domains.PhDIndustrial & Operations EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/108870/1/salu_1.pd

Prosthetic Control and Sensory Feedback for Upper Limb Amputees

Hand amputation could dramatically degrade the life quality of amputees. Many amputees use prostheses to restore part of the hand functions. Myoelectric prosthesis provides the most dexterous control. However, they are facing high rejection rate. One of the reasons is the lack of sensory feedback. There is a need for providing sensory feedback for myoelectric prosthesis users. It can improve object manipulation abilities, enhance the perceptual embodiment of myoelectric prostheses and help reduce phantom limb pain. This PhD work focuses on building bi-directional prostheses for upper limb amputees. In the introduction chapter, first, an overview of upper limb amputee demographics and upper limb prosthesis is given. Then the human somatosensory system is briefly introduced. The next part reviews invasive and non-invasive sensory feedback methods reported in the literature. The rest of the chapter describes the motivation of the project and the thesis organization. The first step to build a bi-directional prostheses is to investigate natural and robust multifunctional prosthetic control. Most of the commerical prostheses apply non-pattern recognition based myoelectric control methods, which offers only limited functionalities. In this thesis work, pattern recognition based prosthetic control employing three commonly used and representative machine learning algorithms is investigated. Three datasets involving different levels of upper arm movements are used for testing the algorithm effectiveness. The influence of time-domain features, window and increment sizes, algorithms, and post-processing techniques are analyzed and discussed. The next three chapters address different aspects of providing sensory feedback. The first focus of sensory feedback process is the automatic phantom map detection. Many amputees have referred sensation from their missing hand on their residual limbs (phantom maps). This skin area can serve as a target for providing amputees with non-invasive tactile sensory feedback. One of the challenges of providing sensory feedback on the phantom map is to define the accurate boundary of each phantom digit because the phantom map distribution varies from person to person. Automatic phantom map detection methods based on four decomposition support vector machine algorithms and three sampling methods are proposed. The accuracy and training/ classification time of each algorithm using a dense stimulation array and two coarse stimulation arrays are presented and compared. The next focus of the thesis is to develop non-invasive tactile display. The design and psychophysical testing results of three types of non-invasive tactile feedback arrays are presented: two with vibrotactile modality and one with multi modality. For vibrotactile, two types of miniaturized vibrators: eccentric rotating masses (ERMs) and linear resonant actuators (LRAs) were first tested on healthy subjects and their effectiveness was compared. Then the ERMs are integrated into a vibrotactile glove to assess the feasibility of providing sensory feedback for unilateral upper limb amputees on the contralateral hand. For multimodal stimulation, miniature multimodal actuators integrating servomotors and vibrators were designed. The actuator can be used to deliver both high-frequency vibration and low-frequency pressures simultaneously. By utilizing two modalities at the same time, the actuator stimulates different types of mechanoreceptors and thus h