Sonovortex: Rendering Multi-Resolution Aerial Haptics byAerodynamic Vortex and Focused Ultrasound
Satoshi Hashizume

Amy Koike

University of Tsukuba
pota1401@hotmail.co.jp

University of Tsukuba
amy23kik@gmail.com

Takayuki Hoshi

Yoichi Ochiai

The University of Tokyo
star@star.rcast.u-tokyo.ac.jp

University of Tsukuba
wizard@slis.tsukuba.ac.jp

CCS CONCEPTS•Human-centered computing →Haptic devices;

KEYWORDS
haptics, air vortex, focused ultrasound
ACM Reference format:
Satoshi Hashizume, Amy Koike, Takayuki Hoshi, and Yoichi Ochiai. 2017.
Sonovortex: Rendering Multi-Resolution Aerial Haptics by Aerodynamic
Vortex and Focused Ultrasound. In Proceedings of SIGGRAPH ’17 Posters,Los Angeles, CA, USA, July 30 - August 03, 2017, 2 pages.
DOI: 10.1145/3102163.3102178

1INTRODUCTION

Aerial haptic feedback is a popular topic in research fields on realworld-oriented interaction, augmented reality (AR), and virtual reality (VR). Various methods such as magnetic force, ultrasound,and air vortices have been proposed for this purpose.
Aerial haptic display has several advantages: it projects a force
from a distance without physical contact or wearable devices, andit has high programmability. In other words, it can be set and rearranged at an arbitrary position in a 3D space because it does not
require physical actuators.
In the this study, we seek to research new aerial interactions. We
aim to develop a new aerial haptics system to express a wide rangeof feedback. The proposed system (Figure 1) combines aerodynamic and acoustic fields. We use the aerodynamic vortex [Sodhiet al. 2013]from the aerodynamic field, and the focused ultrasound[Hoshi et al. 2010] from the acoustic field to develop this device.

2RELATED WORK

Ultrasonic technology possible to provide tactile sensations in midair without encumbering the user with an actuator when using ultrasound [Hoshi et al. 2010]. The position of the focal point canbe changed using a phased array transducer as it is a representation of tactile behavior. Rendering volumetric haptic shapes is also
possible by using focused ultrasound. MidAir [Monnai et al. 2014]reflects a virtual image in the air and provides tactile feedback using an ultrasonic speaker according to the virtual image and fingerSIGGRAPH ’17 Posters, Los Angeles, CA, USA© 2017 Copyright held by the owner/author(s). This is the author’s version of thework. It is posted here for your personal use. Not for redistribution. The definitive
Version of Record was published in Proceedings of SIGGRAPH ’17 Posters, July 30 August 03, 2017, http://dx.doi.org/10.1145/3102163.3102178.

Figure 1: The Sonovortex device.
location. The imperfection of this method is that the foucused ultrasound force is very weak and only limited focal points can begenerated.
An air jet was chosen intuitively to produce contactless haptic feedback with low accuracy. In [Suzuki and Kobayashi 2005],
virtual objects were represented by air jets from an array of nozzles. Vortex rings have also been applied as a non-contact haptic
feedback system. Air vortices have been used to provide impact inmidair [Sodhi et al. 2013] These previous approaches mainly used
vortex rings to add multi-modal sensation to a conventional display. However both of these methods have low fidelity due to thenon-focusing stimulating area.
This study combines multiple haptics technologies as they help
overcome each other’s disadvantages and improve interaction width.
Cross-Field Aerial Haptics [Ochiai et al. 2016] draw tactile interface in the air by combining ultrasonic waves and laser plasmas.
Cross-Field Haptics [Hashizume et al. 2017] is touch type haptics
device that combined magnetic and electrostatic field.

3 IMPLEMENTATION
Our system is shown in Figure 2. An air vortex is a ring of air thattypically has a toroidal shape and is capable of traveling at highspeeds over large distances. Vortex rings can be formed by pushing
air with a piston through a circular aperture, or hole. How well thevortex is formed depends on the volume of air pushed, the velocityof the piston, and the diameter of the aperture.
The ultrasonic haptics is based on acoustic radiation pressure,which is not vibrational and presses the skin surface. This can beapplied on the skin for a long time but this pressure is relatively

SIGGRAPH ’17 Posters, July 30 - August 03, 2017, Los Angeles, CA, USA

Air cannon

Phased array

Displayed areaFigure 2: Aerodynamic and ultrasound system.

(b)

(a)

？
Displayed area(c)

S. Hashizume et al.

4 APPLICATION
4.1 Locating haptic presentation area
Sonovortex can present high resolution haptic and low resolution
haptic at the same time. In addition, by using an air cannon, haptic presentation can be presented to a wide range that ultrasonicwaves can not provide tactile sense. Since the scope of haptic presentation of ultrasound is narrow, it is hard to understand wheretactile presentation is occurring. However, if we show the route to
the presentation range of the ultrasonic tactile with the air cannon(Figure 3(a)), we can easily reach the place where the ultrasonictactile sense is presented. Guiding a disability parson to a tactile
presentation area is possible.

4.2

Tangible display

Air cannon, which is low resolution haptic presentation method,
can move larger things than ultrasonic waves. Therefore, it is possible to display expressions in which relatively large objects suchas leaves and feathers are moved with an air cannon, and fine items
such as petals and Antennae are moved by ultrasonic waves (Figure 3(b)).

4.3

VR and MRSonovortex can be used for VR and MR. In conventional aerial haptic technology, only a single resolution could be presented. Sonovortex can present multiple resolution haptic simultaneously(Figure3(c)) . Therefore, reproducing tactile sensations such as fine shapeand large motion is possible. In the case of butterflies, fine shapes
such as antennae and feet are represented by ultrasound. Large
movements such as butterfliy’s wing movements are expressed withan air cannon. Besides, we can also express the movement of leavesof plants and the shape of branches.

REFERENCES

Figure 3: Application image.

weak (10-20 mN). The sensation is similar to a laminar air flow
within a narrow area.
It’s different in time to have tactile presentation of the aerodynamic vortex and the focused ultrasound. The focused ultrasoundadvances in the air by the speed of sound. Therefore, the focusedultrasound can express almost simultaneously tactile presentation
with the generation of signal. The speed and the delay of the Aerodynamic vortex is larger than the focused ultrasound. The average
speed of aerodynamic vortex device that we used has been shown
to be 7.2m/s. We applied a delay of 30mms in the focused ultrasound in order to make the aerodynamic vortex and the focusedultrasound reach the user at the same time.

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