Tactile Sensation with High Density Pin Matrix
Hands-on Demo Available
Masashi NAKATANI
Hiroyuki KAJIMOTO
Naoki KAWAKAMI
Susumu TACHIThe University of Tokyo
Correspondence tonakatani@star.t.u-tokyo.ac.jp

Motivation and Background
There is a variety of existing been a lot of pin-matrix type tactile displays

KGS

AIST

NIST, 2002

NHK, 2005

What kind of sensations are representable by a dynamic type tactile display?

2.0
1.0

Pop Up!
nakatani et al.,2004

How small of a pin interval is sufficient for conveying tactile information?
Investigate the tactile sensation producedwith an (Ultra) HIGH resolution & FAST response pin matrix tactile display

・Pin motion is strictly vertical・Pins sample the height informationfrom the texture and present tactile
information without any delay

1mm Bakelite

18.6

φ0.8Wagner,
2002

Most of them are Static Presentation / Very few have Dynamic presentation

10m

φ0.9Pawluk,
1998

We developed a pin matrix with a dense pin arrangement, which is driven
mechanically by moving in over the presented texture.

Our solution

φ0.8

Optacon,Bliss,1970

10mm
PM 1P. I. = 1.0 mm

0.45mm

Fig.1 Dimensions of the pin-rod

PM 2
P. I. = 1.5 mm

30mm(P. I. : Pin Interval)

Fig. 2 Profile of the Pin Matrix

Fig. 3 Three types of the Pin Matrix using in the experiment

Experiment 1

Can human recognize the shape withusing a pin matrix?
・Stimuli in psychophysical experiment- an ideal measuring & displaying system

PM 3
P. I. = 2.0 mm

Experiment 2Is edge-perception enhanced by thejumping of the pin-rod?
・Developed driving system

Experiment 3
How important is the pin-interval?
・Comparison with pin-rods with a small tip6mm6mm

0.1mm

0.6mm

0.5mm

1.0mm

1.5mm

1.0mm

tip diameteris 0.5mm

0.1mm
16mm

16mm

16mm

10mm

24mm

(a)

(b)

(c)

(d)

(e)

Etched object shapeSliding underneathFig. 5 Driving a pin-matrix by moving a texture

Fig.4 Shapes using through the experiment

ResultResultThe smaller pin-interval is,
the higher the recognition rates subjects hadBare
FingerPM1(1.0mm)

PM2(1.5mm)

PM3(2.0mm)

Blank

(a)

(b)

(c)

(d)

(e)

100%

100%

100%

100%

100%

100%

100%
83%
100%

83%
83%
33%

33%
17%
33%

67%50%
0%

100%
33%
17%

83%
83%
50%

・Most subjects observed exaggerated edges ofthe shape (spatial derivative effect?)・Some subjects misunderstood the convex
shape and concave shape.

Displacement (mm)・Thin seals (0.11mm) shaped as (a)-(e) are
pasted on to a smooth acrylic board.
・The subjects scanned assigned pin matrix(PM 1, 2, 3) over a prescribed texture.

・Fix the Pin Matrix and driving each pin-rod
・Measured pin-rods movement with a laser
displacement sensor

PM 2PM 4Fig. 7 Additional experiment for evaluating thespace between the pin-rods

Result・Almost all subjects misunderstood PM1and PM4, but not PM1 and PM2.
・The spatial sampling frequency (pininterval) is more important than the spacing
between contact areas.

0.140
0.120
0.100
0.080
0.060

Discussion & Future vision

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Engineering Applications

0-0.0200PM 1100200300

400500Time (ms)

600

700

・Height difference is only 〜 10μm
・Vertical velocity may be predominant
for pin matrix tactile display* Optimal design of a pin matrix type tactile display forinteracting with computer graphics

Scientific Research* Investigate the relative importance of verticaldisplacement for tactile sensation* Research on Active touch vs. Passive touch