Researchers at the University of Pittsburgh have received two grants totaling $500,209 from the National Science Foundation to research walking exoskeletons.
Nitin Sharma, PhD, assistant professor of mechanical engineering and material science at the University of Pittsburgh’s Swanson School of Engineering, will lead the research, which aims to create a hybrid system optimizing the benefits of both functional electrical stimulation (FES) and powered exoskeletons. FES uses low-level electrical currents to activate the exoskeleton wearer’s leg muscles, while powered exoskeletons utilize electric motors mounted on an external frame to move the wearer’s joints.
“We are trying to combine electrical stimulation with robotics to design a control system for a hybrid exoskeleton,” Sharma said in a press release. “It is like a hybrid car switching between a gas engine and an electric motor depending on circumstance. The algorithms we are developing determine when to use power from FES and when to use the power from the motors on the frame.”
Sharma and colleagues will investigate control algorithms through two separate projects. “UNS: Optimal Adaptive Control Methods for a Hybrid Exoskeleton” is funded by the General and Age-Related Disabilities Engineering Division of National Science Foundation (NSF) and will focus on using adaptive control algorithms to allocate optimized control inputs to FES and electric motors during single joint movements. Meanwhile, “Coordinating Electrical Stimulation and Motor Assist in a Hybrid Neuroprosthesis Using Control Strategies Inspired by Human Motor Control” is funded by the Civil, Mechanical and Manufacturing Innovation Division of the NSF and will focus on the use of control algorithms to determine the best synergy between FES-induced multi-joint movements and movements aided by a powered exoskeleton.
Both projects also will investigate exoskeleton efficiency to aid manufacturers in developing hybrid models that use FES technology, powered frames and robotics.
“Current exoskeleton research is using devices completely powered by electric motors. They have huge battery packs and can only provide a maximum of about an hour of continuous walking. With FES, you are using a person’s own muscles to make that person walk. FES also has been shown clinically to improve cardio-vascular fitness, increase muscle strength, and prevent atrophy,” Sharma said.