1.
A Thin Stretchable Interface
for Tangential Force Measurement
Keio University1 / The University of Tokyo2
JST ERATO IGARASHI Design Interface Project3
Yuta Sugiura1,3, Masahiko Inami1,3 and Takeo Igarashi2,3

2.
Interaction with Skin
• People have long made use of their skin to
communicate intentions and emotions to each
other via touching.

3.
Skin-like Interface
• Our interface is
– thin, stretchable, simple configuration and provide
natural haptic feedback like a skin.
• It gives the ability of skin to daily objects
externally.
Smart phone
Home appliance
Furniture Robot

4.
Using this, we can...
• Enable more natural communication with
computer systems.
– Adding skin for robots
– New game controller
– Sensing body movement

5.
Highlights
1) Measurement of stretch of thin
materials using photoreflectors
2) Packaged small sensor module
3) Multi-sensor system that
determines the tangential forces
4) Example applications

6.
Highlights
1) Measurement of stretch of thin
materials using photoreflectors
2) Packaged small sensor module
3) Multi-sensor system that
determines the tangential forces
4) Example applications

7.
Components of the Interface
• Thin stretchable material such as stocking
• Using photoreflector that consist of
– Infra-red LED
– Phototransistor
Phototransistor
Infra-red LED
PhotoreflectorStocking

8.
Photoreflector Stocking
Emitted Light
Reflected Light
Normal condition Material is stretched
Measuring Stretch of Stocking
Transmissivity
Light
• Emitted light pass through the material
when the material is stretched.

9.
Comparison of Sensing Methods
• Strain gauge
– The soft properties is changed.
• Image based sensing [Soap, Baudish 2007]
– Measuring the material’s relative translational
displacement
• Photoreflector (Our approach)
– Measuring the density of material
– Thin
– Low-cost and easily fabrication

10.
Measurement Experiment
• 20 denier stocking
• Pull the stocking by 2mm each time
• Release the stocking
• Measuring 30 times to check the hysteresis
Digital Force GaugePhotoreflector
Stocking

11.
Highlights
1) Measurement of stretch of thin
materials using photoreflectors
2) Packaged small sensor module
3) Multi-sensor system that
determines the tangential forces
4) Example applications

12.
Small Sensor Module
• One photoreflector
• Battery and
Microcontroller are
embedded.
• Coin size
• Wireless
Li-Po Battery (50mA)
Battery
Connector
Photoreflector
Microcontroller
Bluetooth

13.
Highlights
1) Measurement of stretch of thin
materials using photoreflectors
2) Packaged small sensor module
3) Multi-sensor system that
determines the tangential forces
4) Example applications

14.
Multi-sensor System that
Determines the Tangential Forces
Tangential force
Pinch-in
Pinch-out
• Multiple photoreflectors are placed under the
material.

15.
Combination with Conventional
Pressure Sensors
• Detecting normal force and tangential
forces
On pressure sensor array On FuwaFuwa sensor
[Sugiura 2011]

16.
Highlights
1) Measurement of stretch of thin
materials using photoreflectors
2) Packaged small sensor module
3) Multi-sensor system that
determines the tangential forces
4) Example applications

17.
Smart Phone – Flat Type
• Normal touch (Capacitive sense) → Location of object
• Pressure (Skin Interface) → Rotation of object

18.
Smart Phone – Curved Type
• Curved type supports pinching dragging, and
releasing gestures.

19.
Audio Control
• Volume and channel are controlled.

20.
Robot Skin
• Eyes look towards the dragging direction.
• Robot become happy with the pinching action.

21.
Simple Breathing Sensor
• It measures the stretch of a belt placed around
chest.

22.
Other Possible Applications
• As a chair cloth
– Detecting the posture of sitting,
especially slipping
• Sensing muscle movement and
edema
– Continuous human body monitoring

23.
Limitations
• Affected by ambient light such as
sunlight.
• Affected by the user’s hand or
other object.
• Durability of thin material

24.
Related Research
Sheer Gesture,
[Harrison 2012]
Robot Skin,
[Ohmura 2006]
Force Gesture,
[Heo 2011]
Khronos Projector,
[Cassinelli 2005]
GelForce,
[Kamiyama 2006]
rSkin,
[Perner-Wilson 2010]

25.
Conclusion: Enabling Skin-like
Properties in Daily Objects
• Our interface is
– thin, stretchable, simple configuration and
provide natural haptic feedback like a skin.
• Highlights
1) Measurement of stretch of thin materials
using photoreflectors
2) Packaged sensor module
3) Multi-sensor system that determines the
tangential forces
4) Example applications
yuta.sugiura@gmail.com, http://sugiur.com