SAN ANTONIO — A speaker at the American Orthotic Prosthetic Association National Assembly discussed the current state of wearable robotics and how they can be improved.
Kevin Hollander, PhD, founder and director of product development at SpringActive, a biomechanics, robotics and systems design company in Tempe, Ariz., said there are three main problems with traditional exoskeletons – poor fit, biomechanics and lack of intuitive control.
“Control must be continuous in nature. State-based controls lead to mistakes or missed switches,” he said. “Controls must also be time invariant. Time dependency leads to lag in response to changing conditions.”
Hollander added that poor fit could lead to loss of energy transfer, locking out of wearer joints, pinching, skin abrasions and general discomfort.
“The goal of a wearable device is to apply torque to its user,” he said. “In order to do that, it must be properly attached, able to maintain proper joint alignment, portable and lightweight.”
At SpringActive, he said researchers are working to develop more compliant actuation through mechanical springs. They have designed a prototype with 99.9% efficiency and a 300,000 W/kg power to weight ratio.
“Our controllers typically update approximately 1,000 times every second,” Hollander said. “But even if state detection is at 99%, 1 out of 100 steps will lead to a potential fall.”
He said the team will continue to explore novel control methods and plans to develop devices for obesity, elderly assistance and diabetic neuropathy in the future. – by Shawn M. Carter
Hollander K. Paper C10. Presented at: American Orthotic and Prosthetic Association National Assembly; Oct. 7-10, 2015; San Antonio.
Disclosure: Hollander reports he is founder and director of product development for SpringActive.