LEIPZIG, Germany — From an engineering perspective, an exoskeleton has two main characteristics — strength and endurance. The question posed by Homayoon Kazerooni, PhD, professor of mechanical engineering, University of California at Berkley, was how to combine these two properties for the individual. According to Kazerooni, the underlying principal for engineering an exoskeleton is relatively simple: less is more.
“Less is more allows technology to go out of the laboratory and into the market,” he said at the ORTHOPÄDIE + REHA-TECHNIK 2012 International Trade Show and World Congress.
Kazerooni created the Human Universal Load Carrier (HULC), an exoskeleton allowing users to carry loads up to 200 pounds with minimal effort for extended periods of time. Because of the exoskeleton, the user does not feel the weight of the load being carried. The HULC reduces the stress on the knees and the back and eliminates nearly all load forces to the user’s body. The device is not cheap, running as high as $250,000.
As early as 2005, Kazerooni had been interested in creating an exoskeleton for in-home use. But is it possible to create a cheap exoskeleton?
“We changed our military device a great deal,” he said. “We changed the software and made a lot of modifications.”
After testing in California and Virginia, Kazerooni and his team created electronic Lower Extremity Gait Systems (eLEGS). But the device was still expensive and not suited for home use. So what are the compromises engineers must make to create accessible exoskeletons?
“The approach I have been taking the last couple of years is simple and functionally less complex,” he said. “More emphasis on control and less on hardware. That’s the challenge.”
At the World Congress, Kazerooni introduced his modular lightweight exoskeleton for home use. The exoskeleton is 18 pounds and it has four pounds of battery for 3 hours of walking. The price tag is less than $20,000 for the user.
“It’s an affordable system,” he said. “It’s a consumer product.”
Kazerooni H. A novel exoskeleton system for rehabilitation. Presented at the ORTHOPÄDIE + REHA-TECHNIK 2012 International Trade Show and World Congress. May 15-18. Leipzig, Germany.