Pen de Touch
Sho Kamuro*1
The University of Tokyo

Kouta Minamizawa*2
The University of Tokyo

Naoki Kawakami*3
The University of Tokyo

Susumu Tachi*4
Keio University

Figure 1: Proposed device“Pen de Touch”

Figure 2: Internal structure

Figure 3: Prototype system

Figure 4: Use of Pen de Touchin a museum

We propose a pen-shaped handheld haptic display that allows
haptic interactions with virtual environments by generatingkinesthetic sensations on the user’s fingers; the user’s movements
are not restricted since the device does not have mechanicallinkages. Unlike conventional haptic displays that provide
vibrations, which are not representative of tactile sensation, ourproposed device, named “Pen de Touch” (Figure 1), provides
kinesthetic sensations to the muscles in the user’s fingers.
1. Introduction
Various handheld haptic displays have been developed, which are
more easy to use than wearable haptic displays because the userneeds to merely grasp the device to enjoy the haptic interactions.
Human haptic sensations include cutaneous sensations of the skinand kinesthetic sensations produced at the joints of fingers andarms. PHANToM [SensAble Technologies Inc.] is an example of atypical handheld haptic display, which enables a user to perceive
kinesthetic sensations with the help of mechanical linkages, which
are driven by multiple motors. However, this device requires to begrounded, restricting the user’s movements within the range of themechanical linkages. Recently developed portable handheld haptic
displays such as wUbi-Pen [Kyung and Lee 2008] and Senstylus[Fiorentino et al. 2005] can provide haptic sensations without
mechanical linkages. Although such ungrounded devices do not
impose restrictions on the motion performed by users, they canprovide only cutaneous sensations or periodic kinesthetic
sensation. The wUbi-Pen requires the use of physical contacts withthe screen surface and does not function if it is moved in mid-air;on the other hand, Senstylus can provide only vibrations, which do
not satisfactorily represent the realistic feeling of touch. The
development of an ungrounded haptic display that can provide
continual kinesthetic sensations has not been reported thus far.
2. Method
Our proposed haptic device is pen-shaped so that the user can holdthe device in the same way as he or she would hold a writing pen.
In order to downsize the device, we developed our device on thebasis of the hypothesis that the kinesthetic sensations on fingers
alone are sufficient to represent the sensations of touch. An
ungrounded device can not apply an external force to the user’shand; therefore, the point of support and the point of application offorce must be located within the hand itself. We fixed thesupporting point as a point on the base of the index finger and*1 e-mail: sho_kamuro@ipc.i.u-tokyo.ac.jp*2 e-mail: kouta_minamizawa@ipc.i.u-tokyo.ac.jp*3 e-mail: naoki_kawakami@ipc.i.u-tokyo.ac.jp*4 e-mail: tachi@tachilab.org

Copyright is held by the author / owner(s).
SIGGRAPH 2009, New Orleans, Louisiana, August 3–7, 2009.
ISBN 978-1-60558-726-4/09/0008

applied forces to the fingertips by changing the length of thepen-shaped device. Therefore, we developed a haptic display for
haptic augmentation, which the user could use and freely move hisor her hands in mid-air without any restrictions that could beintroduced by the use of mechanical linkages. Figure 2 shows themechanism of working of our proposed device. The device
consists of a part from where the pen is held (grip part) and a base
part. When the device is held in a user’s hand, the base part is
fixed to the base of the user’s index finger, which is inserted in aring attached to the base part; the user grasps the grip part by tip of
the index finger, the middle finger, and the thumb. The motion of
the device is measured by using an optical motion capture system.
When the tip of the device touches a virtual object, the grip part ispulled back toward the base part with the help of the motors,
thereby generating the kinesthetic sensations on the skin andmuscles of the user’s fingers. Inside of the base part, three motors
and strings are fixed, which pull each connecting point in the grip
part and control the 3-DOF motion of the grip part, as shown in
Figure 2. The motion parallel to the central axis generates“pushing” or “pecking” sensations on the fingers, and the motion
perpendicular to the central axis generates the sensation of frictionor the sensation of touching an object by the side of the pen.
3. Application
Pen de Touch is a simple device, which can be easily applied tovarious types of conventional virtual reality environments that are
not haptically augmented. Figure 3 shows a prototype haptic
interaction system interacting with a computer graphics character.
Our haptic display device provides the kinesthetic sensations tothe users depending on the contacts between the pen tip and thevirtual character. The virtual character then moves according to thecontacts from the user, thereby making the virtual reality systeminteractive. As a result, the user experiences the feeling ofcommunicating with the character, as it were actually existing in
the real world. The easy accessibility and good representational
ability of our proposed haptic device has encouraged us to further
develop this device for use in practical systems; as the next step inthis direction, we plan to construct a haptic interaction system for
multiple users, which can be used in a public domain such as amuseum (Figure 4).
References
Kyung, K. and Lee, J. 2008. wUbi-Pen: windows graphical user interface
interacting with haptic feedback stylus, ACM SIGGRAPH 2008 New
Tech Demos.
Fiorentino, M., Uva, A. and Monno, G. 2005. The Senstylus: a novel
rumble-feedback pen device for CAD application in Virtual Reality. In
Proceedings of WSCG 2005.