People paralyzed below the waist who thought they would never take another step could gain some independence thanks to a new exoskeleton, U.S. researchers say.

A powered exoskeleton that enables people with severe spinal cord injuries to stand, walk, sit and climb stairs could be available commercially by 2014, Vanderbilt University reported Tuesday.

Created at the school's Center for Intelligent Mechatronics, its light weight and compact size could give users an unprecedented degree of independence, its developers said.

"You can think of our exoskeleton as a Segway with legs," Michael Goldfarb, professor of physical medicine and rehabilitation, said. "If the person wearing it leans forward, he moves forward. If he leans back and holds that position for a few seconds, he sits down. When he is sitting down, if he leans forward and holds that position for a few seconds, then he stands up."

The 27-pound exoskeleton straps tightly around the torso, and rigid supports are strapped to the legs and extend from the hip to the knee and from the knee to the foot.

The hip and knee joints are driven by computer-controlled electric motors powered by advanced batteries.

A number of researchers have been working on wearable exoskeletons, including a spinoff derived from NASA's Robonaut 2 program that has yielded a 57-pound robotic device would be used as an in-space exercise machine for astronauts to supply resistance against leg movement but could also be used to potentially helping some individuals walk for the first time.

Similar to the Vanderbilt device, it is worn over the legs with a harness that reaches up the back and around the shoulders, with four motorized joints at the hips and the knees

Brian Shaffer, who was completely paralyzed from the waist down in an automobile accident in 2010, has has been testing the Vanderbilt apparatus.

"It's unbelievable to stand up again. It takes concentration to use it at first but, once you catch on, it's not that hard: The device does all the work," he said.

"My kids have started calling me 'Ironman.'"