Muscle-Wire Glove: Pressure-Based Haptic Interface
Cedric Caremel

Gemma Liu

Keio UniversityTokyo, Japan
cedric@keio.jp

Keio Media Design
Tokyo, Japan
gemmaliu@kmd.keio.ac.jp

George Chernyshov

Kai Kunze

Keio Media Design
Tokyo, Japan
chernyshov@kmd.keio.ac.jp

Keio Media Design
Tokyo, Japan
kai@kmd.keio.ac.jp

ABSTRACTThis work follows a novel approach to information presentation
through haptics using muscle-wire. The muscle-wire is extremely
lightweight, silent and does not require complex circuitry. Its property to shrink in length when an electric current is applied, canhave many interesting applications, some of which we present as a
proof of concept of our vision. In this paper, we describe our initial prototype and a �rst series of user tests that demonstrates thepossibility of representing discrete and continuous informations.

CCS CONCEPTS• Human-centered computing → Haptic devices; • Computer
systems organization → Sensors and actuators;

KEYWORDS
Haptic interface; Soft actuators.
ACM Reference Format:
Cedric Caremel, Gemma Liu, George Chernyshov, and Kai Kunze. 2018.
Muscle-Wire Glove: Pressure-Based Haptic Interface. In IUI’18 Companion:
IUI’18: 23rd International Conference on Intelligent User Interfaces Companion,
March 7–11, 2018, Tokyo, Japan. ACM, New York, NY, USA, 2 pages. https://doi.org/10.1145/3180308.3180361

1INTRODUCTION

The concept of cognitive load, developed by John Sweller in thelate 1980s, may have never been as meaningful as today, as weare overwhelmed with visual and auditory stimuli. The averagemobile user consumes hours of data queries without even noticing,whether it is checking the social network status, bank accountinformations or train timetable. After a prolonged exposure of audiovisual sensory interactions, chronic fatigue, a widespread medicalcondition, can occur. Research suggests that cognitive overload
can be linked as a cause, even among healthy individuals [3]. The
purpose of this experimental setup is to test the viability of haptic
cues in daily life scenarios performing at the level of visual cues for
simple tasks. Not satis�ed with the current solutions provided by
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ACM ISBN 978-1-4503-5571-1/18/03.
https://doi.org/10.1145/3180308.3180361

Figure 1: We investigated di�erent parameters to emulate ahaptic feedback on user’s hand (depicted right). Our target
audience at this stage is researchers and experimenters interested in cognition and perception. In this setup, our objective was to evaluate how can the participants perform cognitive tasks, such as getting informations from daily life objects. The early prototype is depicted on the left.
the current standards in haptic interfaces, requiring the use of either
cumbersome servomotors or noisy vibration motors, we developed
a lightweight, soft and silent actuator based on muscle-wires. Thissetup presents the advantage of being mounted directly on theuser’s �nger, so that any physical object can turn into a source ofinformation. In this paper, we will test the accuracy of this device
in representing the information in di�erent daily scenarios.

2RELATED WORK

There is a vast amount of related work using other modalities
than visual cues for status information [1, 4, 5]. Especially, haptic
feedback is gaining popularity for augmented and virtual reality
use cases. There is some related pioneer work by Minamizawa etal., requiring either motors or air tubes and pumping devices [1, 2].
However, so far we don’t know any work using pressure hapticfeedback with muscle-wire.

3EXPERIMENTAL SETUP

For the actuator part, we developed a glove with 3 segments ofmuscle-wire BMF 150 (BioMetal Fiber, Diameter=0.15 mm, TOKICorporation, Japan) wrapping each phalanx of the index �nger
in a ring-like fashion. Each of the segments is providing pressure
by slightly shrinking and thus squeezing the �nger, resulting ina haptic sensation. The prototype is actuated using 3 IRLML6344

IUI’18 Companion, March 7–11, 2018, Tokyo, JapanC. Caremel et al.

Figure 3: Confusion matrices for the experiment 1(A) and2(B)Figure 2: Actuator-driver PCB layout.

power MOSFETs, connected to a NUCLEO-F446RE STM32 board.
We use 10 KHz PWM signal to drive the MOSFETs. The current
through each segment is restricted to 350-500 mA range at 5V. For
safety reasons each segment is isolated using silicon tubes andis �rmly attached to the glove. Each contraction consists of two
distinct events, thereafter named ’hold’ and ’release’. The time atwhich the events occur can be easily and reliably controlled byvarying the current using PWM or voltage regulation. However,we observed that the tensility property of BMF requires a noncompressible delay between its full ’hold’ and ’release’ states, ofapproximately 500ms.

4APPLICATION CASES

We tested 3 di�erent application scenarios with 8 users (Female:4, Male: 4, Age: 19-27, AVG: 23.75, SD: 2.44). In each scenario we
presented the user with some information 10 times and asked users
to what information did they perceive. Users were wearing ourmuscle-wire enabled device during the whole testing session. 2 outof 8 participants had smaller palm size, so were not able to perceive
some of the nuances, especially in the �rst test.
The �rst case is a "Bank Account Balance" test. We briefed the users
on the device setup and the scale we were using, for instance onestrong, long, ’hold’, on on the proximal and intermedial phalanges,
would be equal to 66% available from the credit allowance; a weak
yet repetitive, short, ’hold’, on all the phalanges, suggested insteadthat the account was empty. In total we used 4 possible conditions.
Then the participants were given a credit card, as soon as the card
was touched, a pulse signal was sent, contracting the rings; then thepractitioner was asking what is the card balance. The test resulted
in 81% accuracy. See Fig.3-A
The second session was a "Timing Reminder" test, each ring on
the �nger representing a train station on the Toyoko-line in Tokyo(main line to our campus): the station closest to campus, Hiyoshi,
was represented as the destination on the distal phalanx; Motosumiyoshi, one station away from Hiyoshi station, on the intermedial phalanx; and MusashiKosugi, the furthest station, on theproximal phalanx. Then the users were asked to imagine a scenario
where they are on a train bound to Hiyoshi, and that they will begiven haptic feedback representing the next station on their way.
Then they were presented with a haptic sensation corresponding
to one of the stations and asked what is the next stop. Users wereable to determine the station correctly in 97.5% cases. See Fig.3-B
The last session, we were trying to emulate a progress bar. It isworth noting that we used only 3 rings on the index �nger to represent values ranging from 1% to 100%. We modulate the value using
the timing of "hold" and "release" events on each phalanx. The sequence representing 100% was the following: 0ms - proximal "hold",
250 ms - intermedial "hold", 500 ms - proximal "release" and distal"hold", 750 ms - intermedial "release", 1000 ms - distal "release". The
sequence consists of 1000 ms in total. For lower percentages thesequence was stopped at the time corresponding to the percentage.
E.g. at 53% percent progress the sequence was interrupted at 530ms.
Participants had a short training session, where they were showed
how would 100%, 75%, 50%, 25% and 15% feel like. After that they
were asked to estimate the progress of 10 sequences of random
length. The results show that the average error is 9.61%, SD: 8.28,
SE: 0.93.

5

CONCLUSION

The most interesting �nding of this work is the ability to provide a"data feel" for continuous progress using only discrete stimulations.
Our motivation was, not only to test our hypothesis that we could
achieve an accurate haptic representation of a dataset, but more
importantly, we were keen to demonstrate that the usage of thislightweight haptic technology for a non audio-visual interface isworth investigating. Indeed, we found out that because musclewire is extremely light and compared to other mechanical devices
feels very natural, so that the awareness of the device was declined,
and the focus on the tactile experience is increased. We would beinterested in the future to redesign the glove into an adjustable onesize-�ts-all device and compare it with other conventional hapticdevices (servomotors, linear resonant actuators).

6

ACKNOWLEDGEMENT

We would like to thank all the participants and Takram. This research is partly supported by JST Presto, Grant No: JP- MJPR16D4.

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