Electrotactile feedback applications for hand and arm interactions: A systematic review, meta-analysis, and future directions

Haptic feedback is critical in a broad range of human-machine/computer-interaction applications. However, the high cost and low portability/wearability of haptic devices remain unresolved issues, severely limiting the adoption of this otherwise promising technology. Electrotactile interfaces have the advantage of being more portable and wearable due to their reduced actuators' size, as well as their lower power consumption and manufacturing cost. The applications of electrotactile feedback have been explored in human-computer interaction and human-machine-interaction for facilitating hand-based interactions in applications such as prosthetics, virtual reality, robotic teleoperation, surface haptics, portable devices, and rehabilitation. This paper presents a technological overview of electrotactile feedback, as well a systematic review and meta-analysis of its applications for hand-based interactions. We discuss the different electrotactile systems according to the type of application. We also discuss over a quantitative congregation of the findings, to offer a high-level overview into the state-of-art and suggest future directions. Electrotactile feedback systems showed increased portability/wearability, and they were successful in rendering and/or augmenting most tactile sensations, eliciting perceptual processes, and improving performance in many scenarios. However, knowledge gaps (e.g., embodiment), technical (e.g., recurrent calibration, electrodes' durability) and methodological (e.g., sample size) drawbacks were detected, which should be addressed in future studies.Comment: 18 pages, 1 table, 8 figures, under review in Transactions on Haptics. This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessible.Upon acceptance of the article by IEEE, the preprint article will be replaced with the accepted versio

Electrotactons: designing and evaluating electrotactile cues

Electrotactile feedback is a novel haptic feedback modality that can be used to evoke a desired level of alertness and emotion or convey multidimensional information to the user. However, there is a lack of research investigating its basic design parameters and how they can be used to create effective tactile cues. This thesis investigates the effect of Electrotactile feedback on the subjective perception of specific sensations, such as urgency, annoyance, valence and arousal, to find the number of distinguishable levels in each sensation. These levels are then used for designing structured, abstract, electrotactile messages called Electrotactons. These have potential benefits over vibration-based cues due to the greater flexibility of the actuators. Experiments 1, 2 & 4 investigated the effects of manipulating the basic electrotactile parameters pulse width, amplitude and pulse frequency on perceived sensations. The results showed that all parameters have a significant effect on the perceived sensations, except for pulse frequency not having an effect on valence. Also, pulse frequencies of 30 PPS and above did not influence the perceived sensations. Experiment 3 investigated the use of pulse width, amplitude and pulse frequency to convey three types of information simultaneously encoded into an electrotactile cue. This was the first attempt to design Electrotactons using the basic parameters of electrotactile feedback. The results showed overall recognition rates of 38.19% for the complete Electrotactons. For the individual component parameters, pulse width had a recognition rate of 71.67%, amplitude 70.27%, and pulse frequency 66.36%. Experiment 5 investigated intensity and pulse frequency to determine how many distinguishable levels could be perceived. Results showed that both intensity and pulse frequency significantly affected perception, with four distinguishable levels of intensity and two of pulse frequency. Experiment 6 investigated the use of intensity and pulse frequency from in Experiment 5 to improve the design of Electrotactons on three body locations using two different size electrodes. The results showed overall recognition rates of up to 65.31% for the complete Electrotactons. For the individual component parameters, intensity had a recognition rate of 68.68%, and pulse frequency 94.41%. These results add significant new knowledge about the parameter space of electrotactile cue design and help designers select suitable properties to use when creating electrotactile cues