title: An ankle-foot orthosis powered by artificial pneumatic muscles.
abstract: We developed a pneumatically powered orthosis for the human ankle joint. The orthosis consisted of a carbon fiber shell, hinge joint, and two artificial pneumatic muscles. One artificial pneumatic muscle provided plantar flexion torque and the second one provided dorsiflexion torque. Computer software adjusted air pressure in each artificial muscle independently so that artificial muscle force was proportional to rectified low-pass-filtered electromyography (EMG) amplitude (i.e., proportional myoelectric control). Tibialis anterior EMG activated the artificial dorsiflexor and soleus EMG activated the artificial plantar flexor. We collected joint kinematic and artificial muscle force data as one healthy participant walked on a treadmill with the orthosis. Peak plantar flexor torque provided by the orthosis was 70 Nm, and peak dorsiflexor torque provided by the orthosis was 38 Nm. The orthosis could be useful for basic science studies on human locomotion or possibly for gait rehabilitation after neurological injury.
authors.affiliation: Department of Movement Science, University of Michigan, Ann Arbor, MI 48109-2214, USA.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Ferris
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Czerniecki
authors.forename: Blake
authors.initials: B
authors.lastname: Hannaford
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D032701:Biomimetics / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005684:Gait / Q000502:physiology*; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D009989:Orthotic Devices; D012212:Rheology / Q000295:instrumentation*; D013314:Stress, Mechanical