While other exoskeletons are focusing on getting a wheelchair user walking again, the people at Berkeley Bionics are doing this while trying to mimic the natural human gait with their exoskeleton eLEGS (Exoskeleton Lower Extremity Gait System.). This is not an easy task.
Why is it important to mimic the human gait? Humans step first on the heel when walking, and then roll onto the ball of the foot and toes. A study done in Utah has shown that this normal human movement is much more efficient than, for example, walking constantly on the balls of the feet or on the toes.
But more than just being efficient, the natural human gait is more comfortable than any other type of movement. And if the long term goal of the exoskeleton is to allow a wheelchair user to walk in a normal manner, reproducing the human gait will be essential.
According to Katherine Strausser from UC Berkeley, in an article in Technology Review, eLegs is the first exoskeleton to reproduce the human gait:
"Other mobile exoskeletons--like those developed by companies such as Rex Bionics or Cyberdene--don't try to emulate a natural gait, Strausser says. Because walking is a dynamic motion that is essentially falling forward, Strausser says, many designs opt for a shuffle instead of a natural gait, because "it's safer and a lot easier." However, emulating a natural gait mimics the efficiency of natural walking and doesn't strain the hips, Strausser says."
Tim Swift, a UC Berkeley graduate student in the mechanical engineering department said in an interview with the local UC Berkeley newspaper, the Daily Cal, that mimicking the normal walking traits of a healthy human is one of the primary objectives of the device and also one of its primary difficulties. "There's a reason nobody else has done this before, and that's because nobody knows how to do it," he said.
Read more about exoskeletons for wheelchair users.