A 2D haptic glyph method for tactile arrays : Design and evaluation

Abstract

We present a new framework for information cue rendering on 2D vibrotactile arrays, and we describe an experiment that investigated the feasibility of our approach. The methods are broadly applicable, but our work is motivated by the potential for a tactile array to provide an additional useful channel for information such as location cues related to dataset features or remote user behaviors in visualization systems. Our experiment measured the accuracy with which three basic haptic glyph parameters (position, direction, and an intensity profile) communicated information to users. Results show that multiple parameters can be communicated simultaneously by a glyph, although with reduced accuracy in some cases. In these cases, we give insight into relevant effects to guide the design of improved glyphs. Besides these results, novel contributions of our work are the general information cue approach for 2D arrays (2D haptic glyphs) and the extension of graphical visualization techniques to haptics (glyphs, spatial anti-aliasing, gamma correction). INTRODUCTIONWe present methods for information cue rendering on 2D vibrotactile arrays. To date, most methods have been ad-hoc, with minimal generality. In contrast, the haptic glyph method presented here, combined with our previous rendering work [1], provides a framework that is applicable to a range of 2D array configurations and encompasses and generalizes many of the cues that have been rendered on 2D arrays in past research. Futhermore, it extends previous approaches by considering information cues that encode multiple channels of (potentially) continually-changing information. As an example, we discuss the use of a low-cost palm-sized vibrotactile array to provide information about location and behavior of remote users in a collaborative VR system, i.e., a tactile version of a heads-up map. We briefly introduced the 2D haptic glyph concept in [2], but extend it in this paper and present the first experimental results. The new experiment investigated the feasibility of haptic glyphs by measuring the accuracy with which three parameters could be communicated. Results are promising, especially considering the limitations of the low-cost experiment apparatus and the use of novice subjects. More importantly, results provide specific insight into possible problems and corresponding remedies. MOTIVATION: EXAMPLE APPLICATIONThe use of low-cost vibrotactile elements (tactors) is increasingly common in haptics research and applications. Small vibrating DC motors and Piezo speakers have been used to construct haptic displays with low power requirements, low cost, low weight, portability, and simple implementation. Commonly-explored configurations include elements placed in clothing or used to build arrays on the backs of seats to communicate shape, orientation, direction, or attention cues for both real and virtual environments, e.g., [3][4][5][6]. Experimental studies have verified that such cues can be communicated. Figure 1 shows a 2D vibrotactile array prototype used to tes...

Designing Vibrotactile Codes to Communicate Verb Phrases

“…Borst and Asutay [2005] constructed a low-resolution vibrotactile array with a vibration motor [Vibration Motor 2012] as a means to communicate a sense of touch. They constructed a thirty-element vibrotactile array as a means to communicate sketches [Lipari and Borst 2010; Borst and Baiyya 2009]. We have used a vibration motor and a methodology similar to Borst and Asutay [2005] to construct our tactile display.…”

“…The first method is to use one tactile actuator with temporal-order encoding or different waveforms to represent information [Maclean and Enriquez 2003]. The second method is to increase the number of tactile actuators and use different patterns (shapes) to represent information [Borst and Baiyya 2009]. Usability of the tactile medium depends on the ability of users to distinguish the tactile codes represented by waveforms/shapes [MacLean 2008].…”

A user centric model to design tactile codes with shapes and waveforms

“…Borst et al [3] constructed a low resolution vibrotactile array with vibration motor [1] as a means to communicate a sense of touch. They constructed a 30 element vibrotactile array as a means to communicate sketches which act like touch [12,4]. We have used vibration motor and a methodology similar to Borst et al [3] to construct our tactile display.…”

“…The first method is to use one tactile actuator and temporal order encoding or different waveforms to represent information [13]. The second method is to increase the number of tactile actuators and use different patterns (shapes) to represent information [4]. Usability of a tactile interface depends on the ability of users to distinguish the tactile codes represented by waveforms/shapes [14].…”

BuzzWear

“…Sensory saltation is affected by several factors such as the two-point discrimination threshold in the distance between actuators(TPDT), inter stimuli interval (ISI), saltatory area, and repetition [11]. Borst and Baiyya [3] investigated the recognition accuracy of three parameters (position, direction, and intensity) in a two-dimensional tactile display and revealed that people can interpret multiple parameters in combination.…”