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Engineering Professor Demonstrates Robotic Ankles

DN Staff

June 24, 2010

3 Min Read
Engineering Professor Demonstrates Robotic Ankles

Hugh Herr can phone his ankles.

An associate professor at theMIT-Harvard Div. of Heath Sciences and Technology, he can do that because,after losing his legs 28 years ago, he refused to accept the state of the artin prosthetic technology.

"Sadly, most people with disablingconditions are not well-served by technology," Herr says. "But I predict thatin the twilight years of this century, disabilities will be eliminated."

During a keynote speech at theFreescale Technology Forum (FTF) yesterday, Herr rolled up his pant legs beforea crowd of more than a thousand engineers and bounded up and down the stairs ofthe stage at the Grand Lakes Hotel in Orlando. That's an activity that might bedifficult for individuals with conventional prosthetic legs, as well as formany with "normal" human legs.

But it's not hard for Herr. Using aspringy robotic ankle mechanism that would make Iron Man jealous, Herr hasdeveloped an artificial joint like none that's ever existed.

"When I walk slowly, the computerknows it," Herr says, ambling across the stage. "But when I go up, I get morereflexive power because it knows I'm climbing the stairs."

His ankles are able to do thatbecause he's endowed them with biomechatronic components - a motor, spring, lithium-ionbattery, 12 different sensors and five microcontrollers from Freescale Semiconductor Inc. To reprogram thesoftware in his ankles, he merely contacts their RF transceivers by phone. It'sthe ultimate in artificial limbs, in some ways better than the originals.

Herr was motivated to design thenew limbs after frostbite rendered his legs useless below the knees following amountain climbing incident in 1982. After both legs were amputated, Herr'sengineering motivation went into high gear. He now looks for solutions to allmanner of disabilities, from brain and spinal cord injuries to limbamputations.

"From my experience, I realize thattechnology has the ability to heal, to rehabilitate," he says.

Herr imagines a future whereindividuals wear exoskeletons. He foresees a world in which robotic carpets andfurniture incorporate the ability to soften the blow when the elderly fall. Hepredicts amputees will don robots and then control them with neural interfaces.He even believes that robotic systems will enable commuters to run to work,while barely breaking a sweat. Studies, he says, have proven that when the forceof gravity is reduced by 75 percent, the metabolic rates associated withwalking and running drop by 33 and 72 percent, respectively.

"We think that in the future, peoplewill wear robots when they walk or run," he says. "Why? To save their knees andhips."

His company, IWalk, intends to fit robotic limbs to injuredsoldiers returning from Afghanistanand Iraq.Herr says the robotic limbs will enable the soldiers to enjoy a freedom ofmovement that's remarkably close to what they had before being injured.

"I get calls from people who,through injuries, have lost capabilities," Herr says. "They ask, 'Would itbenefit me to amputate my limb and use a robot?' Remarkably, the answer is moreand more a 'yes.'"

Some day, Herr says, the answerwill always be a resounding yes. To make that day a reality, though, he must keepworking and advancing the state of the art.

"A long time ago, conventionalwisdom would have said, 'Hugh, give up; accept the technology as it is,'" herecalls. "But I'm not going to accept it as it is."

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