title: Preliminary evaluation of a powered lower limb orthosis to aid walking in paraplegic individuals.
abstract: This paper describes a powered lower-limb orthosis that is intended to provide gait assistance to spinal cord injured (SCI) individuals by providing assistive torques at both hip and knee joints. The orthosis has a mass of 12 kg and is capable of providing maximum joint torques of 40 Nm with hip and knee joint ranges of motion from 105° flexion to 30° extension and 105° flexion to 10° hyperextension, respectively. A custom distributed embedded system controls the orthosis with power being provided by a lithium polymer battery which provides power for one hour of continuous walking. In order to demonstrate the ability of the orthosis to assist walking, the orthosis was experimentally implemented on a paraplegic subject with a T10 complete injury. Data collected during walking indicates a high degree of step-to-step repeatability of hip and knee trajectories (as enforced by the orthosis) and an average walking speed of 0.8 km/hr. The electrical power required at each hip and knee joint during gait was approximately 25 and 27 W, respectively, contributing to the 117 W overall electrical power required by the device during walking. A video of walking corresponding to the aforementioned data is included in the supplemental material.
authors.affiliation: Vanderbilt University, Nashville, TN 37235, USA. ryan.farris@vanderbilt.edu
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Farris
authors.forename: Hugo A
authors.initials: HA
authors.lastname: Quintero
authors.forename: Michael
authors.initials: M
authors.lastname: Goldfarb
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D011211:Electric Power Supplies; D004581:Electronics; D004867:Equipment Design; D005684:Gait; D006615:Hip / Q000033:anatomy & histology / Q000502:physiology; D006801:Humans; D007717:Knee / Q000033:anatomy & histology / Q000502:physiology; D007866:Leg / Q000033:anatomy & histology / Q000502:physiology; D035002:Lower Extremity / Q000033:anatomy & histology / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009622:Noise; D009989:Orthotic Devices; D010264:Paraplegia / Q000534:rehabilitation*; D013119:Spinal Cord Injuries / Q000534:rehabilitation; D016138:Walking / Q000502:physiology*