"Long before it's in the papers"
January 27, 2015


Somersaulting robots the next generation of design?

April 26, 2011
Courtesy of the Institute of Physics
and World Science staff

Re­search­ers are try­ing to de­sign ro­bots that mim­ic cater­pil­lars’ abil­ity to curl up and roll with great speed.

Soft-bodied and creepy-crawly ro­bots aren’t new, but these limb­less machines are of­ten very slow—not an ide­al qual­ity for the search-and-res­cue mis­sions for which many such de­vices are de­signed.

Go­QBot starts roll­ing it­self up in prep­a­ra­tion for a som­er­sault. (Cour­te­sy IOP)

Cer­tain cater­pil­lars, though, can curl in­to a wheel and pro­pel them­selves away from preda­tors as­ton­ish­ingly quick­ly. The re­search­ers, from Tufts Un­ivers­ity in Mas­sa­chu­setts, see this as an op­por­tun­ity. Their work is pub­lished April 27 in the jour­nal Bio­in­spira­t­ion & Bio­mimet­ics, along with a vid­eo, al­so on YouTube, of both a cat­er­pil­lar and a pro­to­type ro­bot in ac­tion.

They de­signed a 10 cm (4-inch), soft-bodied ro­bot made of sil­i­cone rub­ber and moved by in­ter­nal coils of al­loyed met­als ca­pa­ble of chang­ing shapes be­fore snap­ping back to their orig­i­nal forms. The de­vice is called Go­QBot be­cause it forms a “Q” shape be­fore roll­ing at over half a me­ter (20 inches) per sec­ond. It’s fit­ted with five infrared-light emit­ters on its side to al­low for sys­tem­at­ic mo­tion track­ing.

In real cater­pil­lars, bal­lis­tic roll­ing only works well in a lim­it­ed range of situa­t­ions be­cause it takes plen­ty of pow­er, of­ten ends un­pre­dictably and is in­ef­fi­cient on rough sur­faces, the develope­rs said. None­the­less, they pre­dict they will be able to mus­ter enough con­trol in their ro­bots to let them wheel with haste in­to a dan­ger zone be­fore wig­gling deepe­r in­to trou­ble spots.

There are many ro­bots that move fast by roll­ing, but they strug­gle to get in­to dif­fi­cult spaces, not­ed Huai-Ti Lin, lead au­thor of the stu­dy.

“Limb­less crawl­ing ro­bots with bal­lis­tic roll­ing ca­pa­bil­ity could be de­ployed more gen­er­ally at a dis­as­ter site such as a tsu­na­mi af­ter­math,” he said. “The ro­bot can wheel to a de­bris field and wig­gle in­to the dan­ger for us.” He added that the bots might be use­ful for “ur­ban res­cue, build­ing in­spec­tion, and en­vi­ron­men­tal mon­i­tor­ing.”

* * *

Send us a comment on this story, or send it to a friend


Sign up for

On Home Page         


  • St­ar found to have lit­tle plan­ets over twice as old as our own

  • “Kind­ness curricu­lum” may bo­ost suc­cess in pre­schoolers


  • Smart­er mice with a “hum­anized” gene?

  • Was black­mail essen­tial for marr­iage to evolve?

  • Plu­to has even cold­er “twin” of sim­ilar size, studies find

  • Could simple an­ger have taught people to coop­erate?


  • F­rog said to de­scribe its home through song

  • Even r­ats will lend a help­ing paw: study

  • D­rug may undo aging-assoc­iated brain changes in ani­mals

Researchers are trying to design robots that mimic caterpillars’ ability to curl up and roll with great speed. Soft-bodied and creepy-crawly robots aren’t new, but these limbless machines are often very slow—not an ideal quality for the search-and-rescue missions for which many such devices are designed. Certain caterpillars, though, can curl into a wheel and propel themselves away from predators astonishingly quickly. The researchers, from Tufts University in Massachusetts, see this as an opportunity. Their work is published April 27 in the journal Bioinspiration & Biomimetics, along with a video, also on YouTube, of both a caterpillar a prototype robot in action. They designed a 10 cm (4-inch), soft-bodied robot, called GoQBot, made of silicone rubber and moved by internal coils of alloyed metals capable of changing shapes before snapping back to their original forms. The device is called GoQBot because it forms a “Q” shape before rolling at over half a meter (20 inches) per second. It’s fitted with five infrared-light emitters on its side to allow for systematic motion tracking. In real caterpillars, ballistic rolling only works well in a limited range of situations because it takes plenty of power, often ends unpredictably and is inefficient on rough surfaces, the developers said. Nonetheless, they predict they will be able to muster enough control in their robots that they can wheel with haste into a danger zone before wiggling deeper into trouble spots. There are many robots that move fast by rolling, but they struggle to get into difficult spaces, noted Huai-Ti Lin, lead author of the study. “Limbless crawling robots with ballistic rolling capability could be deployed more generally at a disaster site such as a tsunami aftermath,” he said. “The robot can wheel to a debris field and wiggle into the danger for us.” He added that the bots might be useful for “urban rescue, building inspection, and environmental monitoring.”