Water walking robots

जुलाई 20, 2007 at 9:10 अपराह्न टिप्पणी छोड्नुहोस्

 
JESUS BUGS:  So called due to their water-walking skills, water striders even mate on water [bottom]. Their mechanical counterpart, a STRIDE bug [top], is no pushover either.

As if signing books and performing surgery on patients were not enough, robots can now walk on water surface too.This insectlike mechanical robots with four to sixteen legs. The “bugs,” two to six inches long and weighing a few grams, can scoot over water, thanks to engineers at Carnegie Mellon University (CMU).  What started as a class project three years ago ended up, reports IEEE Transactions on Robotics. Called STRIDE, for surface tension based robotic insect dynamic explorer, the robots use water’s surface tension to amble on their spindly legs exactly like water striders, the insects that motivated the challenge.

Surface tension, the force that produces the lovely teardrop shape of dripping water, also resists surface ruptures. That is why, for example, a thin sewing needle can be placed on a slip of tissue paper on water, and the needle will stay afloat even after the tissue becomes waterlogged and sinks. This is very different from the buoyant force that keeps ships floating, because unlike a ship, the needle is in fact on average denser than water and will sink if gently nudged downward. This experiment works better if the needle has a hydrophobic—or water repellent—coating such as Teflon (like the surface of nonstick pans).

CMU’s water-walking robots use the force of surface tension on Teflon-coated legs a few hundred microns thick and two to four inches in length to keep themselves above water. To move and turn, they use “a sculling motion, [where] during the front stroke the leg is in the air, and during the reverse stroke the leg is pushing water [but] never breaking the water surface,” says principal investigator Metin Sitti. This is exactly how water-striders move, although their peak speeds are around five feet per second, compared with several inches a second for these robots.

Science Image
FLOATING CURRENCY:  Surface tension keeps a coin from sinking. A gentle downward nudge will break the water’s surface and sink the coin, because the metal is denser than the water.

What limits their speed? Although the robots pump their legs much faster than the insects (40 times a second , as opposed to no more than 10 for the insect), the strokes are much shorter and, moreover, the robots are a hundred times heavier than the insects. “If you scale down the system, you become much more power-efficient and agile,” Sitti says about the insects’ superior speed.

But a higher speed isn’t the only goal; a single water-strider leg can support 15 times the body weight of the insect, whereas a mosquito leg on water can support 23 times its body weight — compared with only about half a body weight per leg for a robotic bug. Furthermore, insects routinely sink below water’s surface due to rain or turbulence, but always manage to resurface . Both of these impressive abilities are due to microscopic hairs on their legs, which, in addition to making their legs more hydrophobic, also trap air that acts like a buoyancy cushion or life jacket. Sitti is trying to mimic that feature using hair from geckos’ feet on his robots’ legs; microfabrication of synthetic hairs may come later. He is also trying to use non-Teflon coatings that are more hydrophobic, like that used on Gore-Tex boots.

These bugs “are really cheap to manufacture on a large scale, because they’re really simple,” Sitti explains, which makes them prime targets for several applications. Besides their educational and entertainment value, these robots can be used for environmental monitoring of still-water ecosystems like ponds and marshes. They can walk on water as shallow as a tenth of an inch, and carry sensors that transmit information back to the shore, functioning as minimally invasive probes, and opening up a whole new form of bugging.

Source-ScientificAmerian

Entry filed under: Creative, engineering, technology. Tags: .

20 Richest Women from Entertainment Actress undresses to protect animals

जवाफ लेख्नुहोस्

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Trackback this post  |  Subscribe to the comments via RSS Feed


नेपालको समय र तापमान

छिमेकिको दैलोमा चिहाउने कि ?

RSS नेपाल प्लस

  • ईटालीको ब्यापारिक मेलामा नेपालीपनि
    इटालीको उत्तरपूर्वी शहर पादोभा संपन्न छ । सुसंस्क्रित छ । यहाँ वार्षिक रुपमा ब्यापारिक मेला लाग्छ । अहिले एशियाली अर्थात तिनको भाषामा ओरिएन्टल मेला लागिरहेको छ । यसको अर्थ एशियाली हस्तकला, संस्क्रिति र ब्यापारिक सामग्रिलाई प्रोत्साहन गर्ने, चिनाउने हो । यसमा थोरै नेपालीले भाग लिएका छन् । एभेरस्ट क्राफ्टका तर्फबाट एन आर एन स्विजरल्याण्डका पूर्व […] […]
    admin

RSS अनलाइन खसखस

  • फिरफिरे, बुद्धिसागरको नयाँ उपन्यास बजारमा आउने तयारी गर्दा कभर फोटो बिवाद
    बुद्धिसागरको नयाँ उपन्यास "फिरफिरे" बजारमा आउने तयारी गर्दा कभर फोटो बिवाद शुरु भएको छ । स्टक फोटोलाइ कभरमा राख्दा चोरिको भएको वा प्रयोगको लागि पुर्ण अधिकार नभएको अनलाइन सोसल मिडियहरुमा शंका गरिएका थिए ।त्यस्ता शंकाहरुको जवाफमा बुद्धिसागरले कसैले मुद्धा हालिदिएमा सृजनात्मक चोरीमा धेरै फाइन तिर्नु पर्ने हुनाले आफुले त्यस्तो जोखिम नउठाउने बताएका छन् […]
    noreply@blogger.com (RB)

RSS हाम्रो ब्लग

  • An error has occurred; the feed is probably down. Try again later.

RSS The road to Nowhere goes everywhere….

  • प्लाष्टिकका झोला:प्रतिबन्ध कि पुनर्प्रशोधन?
    एक महिनाजति पहिलेपोखराबाटप्रकाशितहुनेएउटादैनिकमाछापिएको एउटा समाचारको शीर्षक थियो ‘पोखरामा प्लाष्टिकका झोला तथा गिलास मुक्त नगर घोषणाको तयारी पुन: शुरु’। उक्त समाचारको शिर्षकले मेरो मनमा दुईवटा वैकल्पिक अर्थ सुझाएको थियो। पहिलो, पोखरामा यस्तो घोषणा पहिल्यै गरिसकिएको तर त्यो असफल भएको र यसैले फेरि घोषणा गर्न आवश्यक परेको। दोश्रो, पहिला तयारी गरेर पनि घोषणा गर […]
    Basanta

RSS मेरो बिचार र अभिव्यक्तिको साझा चौतारी

  • के भएको थियो ९० सालको भूकम्पमा ?
    यही वैशाख १२, १३ र २९ का ठूला भूकम्प र त्यस बीचमा गएका सयौं का परकम्प र ‘धक्का’ सँगै नेपालमा घटेका विगतका ठूला भूकम्पको बारेका खोज र कौतूहल पनि बढेको छ । भूकम्प मूलतः प्राकृतिक घटना भएपनि ठूला भूकम्पहरू एउटा “अविस्मरणीय खाटा”का रूपमा देशको इतिहासमा रहन्छन् । अहिलेको विनाशकारी भूकम्पभन्दा अगाडिको कुरा गर्ने हो भने ९० साल अर्थात् सन १९३४ को भूकम्प नै नेपालको ल […]
    Dilip Acharya

मेरो ढुकुटी

अनलाईन कती जना ?

who's online

यो साइट १४ अप्रिल २००७ देखी

Web Page Counter
Free Web Counters

औ पटक हेरी सकिएको छ ।

Calander

जुलाई 2007
M T W T F S S
« Jun   Aug »
 1
2345678
9101112131415
16171819202122
23242526272829
3031