Flexible Sensors Make Robot Skin

Roland Piquepaille writes "In recent years, lots of efforts have been made to give robots the ability to hear and see. But what about the sense of touch? Unlike us, robots don't have sensitive skin. But this is about to change. By using organic, or plastic, field-effect transistors as pressure sensors deposited on a flexible material, researchers at the University of Tokyo have created an artificial skin which will give robots the sense of touch. The prototype has a density of 16 sensors per square centimeter, far from the 1,500 of our fingertips. When this density increases and when the problem of the reliability of this kind of transistors is solved, the researchers say this artificial skin will also be used for car seats or gym carpets. Expect to see them in four or five years. More details and a picture of a robotic hand using organic transistors as pressure sensors."

Comments

Roland Piquepaille writes nothing

[Anonymous Coward]

he just plaigarises other peoples content

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Roland Piquepaille writes nothing

[Anonymous Coward]

he just plaigarises other peoples content and sells it on his blog

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Complaining Robots

[A Boy and His Blob]

Oh great, one more thing for Marvin to complain about.

I think you ought to know I'm feeling very depressed, and my leg hurts too.

Article repost and image

[Anonymous Coward]

http://radio.weblogs.com/0105910/images/flexible_s kin.jpg
Flexible Sensors Make Robot Skin

In recent years, lots of efforts have been made to give robots the ability to hear and see. But what about the sense of touch? Unlike us, robots don't have sensitive skin. But this is about to change. By using organic, or plastic, field-effect transistors as pressure sensors deposited on a flexible material, researchers at the University of Tokyo have created an artificial skin which will give robots the sense of touch . The prototype has a density of 16 sensors per square centimeter, far from the 1,500 of our fingertips. When this density increases and when the problem of the reliability of this kind of transistors is solved, the researchers say this artificial skin will also be used for car seats or gym carpets. Expect to see them in four or five years. Read more...

Here are selected excerpts from the Technology Research News article.

Researchers from the University of Tokyo have devised pressure-sensor arrays that promise to give objects like rugs and robots the equivalent of one aspect of skin -- pressure sensitivity.

The researchers' pressure sensor arrays are built from inexpensive organic, or plastic, transistors on a flexible material. This allows for dense arrays that can be used over large areas.

The arrays could be used in pressure-sensitive coverings in hospitals, homes, gyms and cars to monitor people's health and performance, and eventually as skin that would give robots the means to interact more sensitively with their surroundings, said Takao Someya, an associate professor of electrical engineering at the University of Tokyo.

The sensor skin works even when rolled around a cylinder as small as 4 millimeters in diameter, said Someya. The researchers' prototype is an eight-centimeter-square sheet containing a 32-by-32 array of organic sensors -- a density of 16 sensors per square centimeter. In contrast, humans have 1,500 pressure sensors per square centimeter in the fingertips, though far fewer in most other places.

Here is a picture of a robotic hand using organic transistors as pressure sensors. (Credit: Takao Someya)

And what are possible applications?

The active-matrix design allows the arrays to be smart enough to enable specific sensors at certain feedback points to, for instance, monitor the heart and breathing rate of a hospital patient who has fallen to the floor, said Someya. The skin could measure whether an elderly patient is just taking a rest, or needs help, he said.

The skin could also be used in car seats to monitor drivers' mental and physical conditions, Someya said. "Our large-area pressure [sensing abilities] would be helpful" in obtaining information through drivers seats, he said.

And, of course, we'll see home robots able to pick an egg in the fridge.

The research work has been published by the Proceedings of the National Academy of Sciences on July 6, 2004, under the title "A large-area, flexible pressure sensor matrix with organic field-effect transistors for artificial skin applications." Here is a link to the abstract .

Re:Prosthetics

[Impeesa]

Exactly - by applying sensations straight to the skin, you're whitewashing a huge number of nerves with the same sensation. With such inefficient input to the nervous system, you'd have pads and stuff all the way up your arm just to transmit the kind of data this skin could generate. It can't be used efficiently until we can more accurately send signals to just a small number of nerves at once.

Re:yeah, right!

[blakestah]

You can sense the difference between two and one point on your skin when they are separated by a little less than a mm.

Low threshold mechanoreceptors, of two different types, each have about 1/mm2 density in the fingertip, or about 100/sq cm. These two types are different in temporal sensitivity and dynamic range, but allow sensation of skin deflections from a few microns to a few millimeters - roughly three orders of magnitude range.

16 will not allow a reasonable assessment of surface texture. It will not allow you to discriminate 100 grit from 200 grit sandpaper. It will not allow you to read Braille, or find the right key in your pocket.

But certainly it will allow lots of function.

Re:Why this is not going to help much + a better w

[Animats]

The problem is not that you can't do it. It's that the market is so dinky that tooling up to do it isn't worth it.

It should be feasible to make integrated silicon strain gauge/amplifier/interface chips, embed them in a flexible printed circuit, and laminate them into a skin-like laminate with appropriate tough, soft, and hard layers. But the processes involved are all high-volume ones - it's hard to do this economically in small volume. And there's no market for a process that turns out big rolls of this stuff.

There's a lot of stuff in robotics that's like that. Linear motors and laser scanners both cost about 20x what they should. because the volume is tiny. Even basic servomotos and servo amps cost 5x as much as they should, based on parts cost.

It's getting better, though. More and more parts needed in robotics are becoming off the shelf. I run a DARPA Grand Challenge team, and over the last year, many of the components you need for that have become far more available.

Re:God solved this problem with hair

[uglyduckling]

Utter rubbish.

I'm a med student - I had to respond to this one. There are 6 types of tactile receptors, of which nerve endings attached to hairs are one. Hairs provide basic information about movement - the wind or your clothes moving past your skin etc.

The tips of your fingers are hairless. That's obvious - look at them under a magnifying glass or microscope if you have one. Fine touch sensation is provided by Tactile Discs and Tactile Corpuscles located in the ("live") skin of the dermis. The skin is not made exclusively of "dead" cells, but of many layers, and the ("dead") epidermis at the surface is quite capable of transmitting movement down to these cells.

You can check all of this out if you want.

People have hair on their heads mainly for insulation (get a crew cut in the middle of winter if you want to prove this!) although I agree that hair on the head has a limited use in avoiding collisions. I suspect that subjective loss of sensation in the face after shaving is due to the trauma of having run a blade over your skin, and the stinging sensation from the damage to hair follicles.