title: Feasibility of a Hydraulic Power Assist System for Use in Hybrid Neuroprostheses.
abstract: Feasibility of using pressurized hydraulic fluid as a source of on-demand assistive power for hybrid neuroprosthesis combining exoskeleton with functional neuromuscular stimulation was explored. Hydraulic systems were selected as an alternative to electric motors for their high torque/mass ratio and ability to be located proximally on the exoskeleton and distribute power distally to assist in moving the joints. The power assist system (PAS) was designed and constructed using off-the-shelf components to test the feasibility of using high pressure fluid from an accumulator to provide assistive torque to an exoskeletal hip joint. The PAS was able to provide 21 Nm of assistive torque at an input pressure of 3171 kPa with a response time of 93 ms resulting in 32° of hip flexion in an able-bodied test. The torque output was independent of initial position of the joint and was linearly related to pressure. Thus, accumulator pressure can be specified to provide assistive torque as needed in exoskeletal devices for walking or stair climbing beyond those possible either volitionally or with electrical stimulation alone.
authors.affiliation: Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Foglyano
authors.affiliation: Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
authors.forename: Rudi
authors.initials: R
authors.lastname: Kobetic
authors.affiliation: Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Curtis S
authors.initials: CS
authors.lastname: To
authors.affiliation: Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Bulea
authors.affiliation: Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Schnellenberger
authors.affiliation: Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Musa L
authors.initials: ML
authors.lastname: Audu
authors.affiliation: Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Nandor
authors.affiliation: Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Roger D
authors.initials: RD
authors.lastname: Quinn
authors.affiliation: Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Orthopaedics, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Triolo