GROUNDBREAKING SCIENCE
Carrying Your Weight

In pursuit of a super-strength suit, ORNL's François Pin helped identify an energy source and devise a wearable exoskeleton "foot" interface to amplify the wearer's physical strength.

An ORNL developed interface for the foot has produced excellent results. The work could lead to a wearable exoskeleton that will increase the wearer's physical strength.

In Iraq last summer, while enduring blistering heat from the desert sun, young American soldiers sometimes struggled to move while carrying 125-pound backpacks. Last spring, soldiers on aircraft carriers hoisted bombs into fighter jets using long attachments called hernia bars. It seems possible that many of these soldiers will someday undergo hernia, shoulder, and back surgeries.

"In an age of advanced technological developments that has brought satellites, missiles, unmanned aerial and ground vehicles, and high-tech aircraft and weapons, we have put too little emphasis on helping humans in such tasks as lifting heavy objects," says François Pin, an ORNL robotics scientist whose team once developed a robot that enabled a person exerting 10 pounds of force to lift and control a 5000-pound payload. "Many of our construction, manufacturing, and military personnel carry extremely heavy loads. We are injuring our work force. Those injuries are costing the nation billions of dollars in health care and disability insurance."

Pin believes the answer lies in wearable robotics, an emerging technology that could lead to the exoskeleton and ultimately the "super-strength suit." He thinks it is time to focus technological development on human assistance and amplification.

"In just a few years, we could have robots that will help humans in materials handling, manufacturing assembly operations, and rescue operations, such as rubble removal and casualty evacuations," he says. "Wearable robotics will be used to improve the strength and stability of human movements. The technology can help the elderly get out of their chairs more easily and give the handicapped more control of their bodies."

He points out that surgeon-assist robotics are already in use for eye and plastic surgeons to ensure that their movements during surgery are precise, controlled, and tremor-free. In eye surgery, automated laser equipment is used to make precise cuts.

Pin and his colleagues have received funding from the Department of Defense to conduct research toward designing an exoskeleton to make each soldier faster, stronger, and tougher. Building a workable exoskeleton, he says, will require solutions to challenging technological problems.

First, the exoskeleton must be powered by an external energy supply that is safe, silent, light, and not too hot or hazardous. ORNL researchers believe an excellent candidate is a small fuel cell powered by hydrogen generated on demand and in a controlled manner from sodium borohydride through a catalytic reaction.

Second, an actuator is needed to transform the energy into mechanical motion at the joints. The actuator should make the exoskeleton responsive enough to help, rather than hinder, the wearer's movements. "When you stumble," Pin says, "the exoskeleton should help you recover rather than make you fall."

Third, haptic interfaces between the exoskeleton and the human must be just right so that skin is not damaged while precise sensing is achieved. "We decided the best areas for transfer of load are the foot, waist, shoulder, and wrist," Pin says. "We obtained excellent results in our test interface for the foot."

The fourth challenge is to develop high-tech sensing and controls. "Our goal," says Pin, "is to develop wearable robotics that are 'transparent' in the sense that they will augment a human's physical abilities without either being felt or hindering any other function. Our experimental results with our new controls test stand show very smooth tracking of the human's limbs and complete stability during accidental impacts or intentional contacts, such as foot steps, even when carrying backpack loads as heavy as 200 pounds. These results are extremely promising for a variety of applications, particularly smart prosthetics and materials handling."

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