Cross-Field Haptics: Push-Pull Haptics Combined with
Magnetic and Electrostatic Fields
Satoshi Hashizume∗, Kazuki Takazawa, Amy Koike, Yoichi Ochiai
University of Tsukuba

Figure 1: (a) The user feels the paramecium caudatum sensation from the surface; (b) Electromagnet array layer; (c) Magnetic fluid layer;(d) Conductive electrode layer
Keywords: haptic devices, cross-field, magnetorheological fluid,
electrovibration

on a film that covers MRF to generate adsorption force from theelectrostatic field to develop this device.

Concepts: •Human-centered computing → Haptic devices;

We compared tactile sensation for single field and multiple fields.
Through verification, it was determined that haptics feedback using
multiple fields provides a wide range of tactile sensations comparedwith that using a single field. By combining different types of force(e.g., pull and push) simultaneously, the proposed system can display various textures. To the best of our knowledge, this is early
study that combines multi-field physical quantities to render haptic textures. The electrostatic and magnetic fields do not influenceeach other. Further, from the experiment, it was determined that thefields do not influence each other’s tactile presentation.

1Introduction

The representation of texture is a major concern during fabricationand manufacturing in many industries. Thus, the approach for fabricating everyday objects and the digital expression of their textures
before fabrication process has become a popular research area. Although it is easy to change the texture of objects in the digital world(i.e. just setting texture parameters), it is difficult to achieve this in
the real world.
Tactile feedback allows displaying texture and affordance of contacts to users. In conventional studies, interaction using tactile
feedback has been actively researched. Most haptic feedback systems currently being studied are categorized into two areas; wearable or non-wearable devices. Tactile feedback using wearable devices often uses force feedback devices, e.g., users wear the feedback devices on their arm or fingertips. Wearable devices can provide strong tactile feedback and tactile presentation for any condition. However, it is difficult to implement larger wearable devices to mount on the user. On the other hand, tactile feedback
with non-wearable devices mainly utilizes environmental-type tactile displays such as magnetic field, electrostatic field and acoustic
fields. Because the user does not necessarily wear the device, theuser’s load becomes a low-level load.
In present study, we aim to research new material interactions as
environmental-type tactile display. We aim to develop a new tactile
display to express various textures. The proposed system physically deforms and changes the physical force between the finger
and the device. To achieve this, we combine magnetic and electrostatic fields. We utilize magnetorheological fluid (MRF) which is
flexible liquid affected by the magnetic field, and electrovibration∗ e-mail:s1513110@u.tsukuba.ac.jp
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c 2016 Copyright held by the owner/author(s).
the owner/author(s). ⃝SIGGRAPH ’16, July 24-28, 2016, Anaheim, CA,
ISBN: 978-1-4503-4371-8/16/07
DOI: http://dx.doi.org/10.1145/2945078.2945108

2 Related Works
MRF is mainstream medium for tactile presentation used with magnetic field. MRF is a fluid that changes viscosity as per the given
magnetic field. It is possible to express the softness of the object bychanging the viscosity of the magnetic fluid and it is also possible
to express bumpy through fluid vibrations. MudPad [Jansen et al.
2010] which use MRF, has a very low reaction time and can provideinstant multi-point feedback for multitouch inputs. In this study, weemploy MRF and magnetic field to render “push” haptic feedback.
Adding to MRF, we present haptic feedback using a techniquecalled electrovibration [Mallinckrodt et al. 1953] as “pull” haptic
feedback. Electrovibration creates a rubbery feeling when dragging a dry finger over a conductive surface covered with a thin insulating layer excited with a high voltage signal. TeslaTouch [Bauet al. 2010] uses electrovibration, which adds a signal to an electrode. Am interaction display and a touch display were developed
using electrode without a power unit. REVEL [Bau et al. 2012]
employs TeslaTouch for AR. Electrovibration can provide haptic
feedback without using a complicated actuator and device. However, it is necessary to move a finger because tactile presentationis related to the electrostatic force generated between a finger andthe surface. Therefore, it is impossible to provide one point haptic
feedback such as button.
This study combines multiple haptics technologies as they help
overcome each otherfs disadvantages and help improve interaction
width. Cross-Field Aerial Haptics [Ochiai et al. 2016] draw tactileinterface in the air by combining ultrasonic waves and laser plasmas. Cross-field haptics is not a widely studied in haptic areas. To
explore haptic display areas, we decided to use the electrostatic andmagnetic fields simultaneously. The magnetic field generates forceInsulator
Conductive Electrode
Mgnetic Fluid
Electromagnet Arry

Projector
CameraPC

Figure 3: Wool texture rendering (left) and reproduction of theheart motion (right)
electrode with a signal generator based on a tracked coordinate.

Signal Generator
Haptics Device

Figure 2: System Overview
to push up and down using MRF. The electrostatic field generates
force go down in the right and left directions using electrovibration. The top, bottom, right and left directions can be produced by
combining the power generated to pull with the power generated topush.

3Implementation

The device consists of an electromagnet array layer, a magnetic
fluid layer, and a conductive electrode layer (upper Figure 2). MRF
is a liquid whose viscosity changes in response to a magnetic field.
When no magnetic field is provided, the MRF acts as a Newtonian
fluid such as water. However, in non-Newtonian fluids (Binghamfluids) such as butter, if a magnetic field is provided the viscosity islinearly controllable using a magnetic field. MRF is controled using
an electromagnet. Further, to ensure that a groove of the magnetic
field is not created on the screen, 12 coils (three vertical and fourhorizontal) are laid on the 12 mm×17 mm screen. In this study wefocused on the upward force of MRF. When viscosity changes, theforce pushing up the finger by vibration created by switching themagnetic field in the electromagnet.
Electrostatic force part uses a conductive electrode. This part ofsystem provides haptic feedback using electrostatics adhesion. Further, it also provides high-voltage electric vibration to the electrode.
When a body is connected to GND and an electrode is struck, force
is generated. Force is generated in the direction where a movement is resisted; therefore, the frictional force is generated. In thisstudy, a transparent conductive film on the electrode, the insulation
coating agent (Hayacoat), was applied as the insulating layer. The
insulator is pitched by the electrode and the finger, and therefore,
electric current does not flow into the human body. Even if it flows
into the human body, it is restricted to 0.5 mA electric current, as
there are constant current diodes of 0.5 mA on the GND side that isconnected to the human body.
Arduino DUE and a personal computer are used for the control of acircuit (lower Figure 2). A finger that attached a marker is tracked
with a camera, and the tracking position is used as input. A projector sends the image to a device based on the location of the trackedfinger. An electronic signal is sent to the electromagnet and the4 Application
Application to express various texture is possible (Figure 3 left). Inorder to do this, we change the frequency of the signal which add
to electrode and electromagnet. TeslaTouch express texture using
friction, our application express texture using the force of magnetic
fluid in addition to friction.
Cross-field haptics can express the body tissue such as the heart andthe liver (Figure 3 right). In the medical field such as the operations,accurate movement to match the state of the body tissue is essential. The exact behavior is performed easily if the body tissue canbe expressed. To reproduce the organs, the texture of the surface,viscosity such as softness, and vibration such as pulsation is a needto express. Texture can expressed in electrovibration, the viscosityand vibration expressed using the MRF.
We understood that width of the sense of touch presentation spreadfrom an experiment of cross-field haptics. The haptics feedback
only for electrovibration can not provide tactile for a immobile finger, although this display can provide tactile for a immobile finger
by combining electrovibration with MRF. However, there are someproblems. Because of vibration by the MRF is big, friction feelingof electrovibration may be lost. It is necessary to regulate electricity
to add to an electromagnet.

References
BAU , O., P OUPYREV, I., I SRAR , A., AND H ARRISON , C. 2010.
Teslatouch: Electrovibration for touch surfaces. In Proceedingsof the 23Nd Annual ACM Symposium on User Interface Software
and Technology, ACM, New York, NY, USA, UIST ’10, 283–292.
BAU , O., P OUPYREV, I., L E G OC , M., G ALLIOT, L., AND G LIS SON , M. 2012. Revel: Tactile feedback technology for augmented reality. In ACM SIGGRAPH 2012 Emerging Technologies, ACM, New York, NY, USA, SIGGRAPH ’12, 17:1–17:1.
JANSEN , Y., K ARRER , T., AND B ORCHERS , J. 2010. Mudpad:
Tactile feedback and haptic texture overlay for touch surfaces.
In ACM International Conference on Interactive Tabletops andSurfaces, ACM, New York, NY, USA, ITS ’10, 11–14.
M ALLINCKRODT, E., H UGHES , A. L., AND S LEATOR , W. 1953.
Perception by the skin of electrically induced vibrations. Science118, 3062, 277–278.
O CHIAI , Y., K UMAGAI , K., H OSHI , T., H ASEGAWA , S., AND
H AYASAKI , Y. 2016. Cross-field aerial haptics: Rendering haptic feedback in air with light and acoustic fields. In Proceedingsof the 2016 CHI Conference on Human Factors in Computing
Systems, ACM, New York, NY, USA, CHI ’16, 3238–3247.