title: Angular-velocity control approach for stance-control orthoses.
abstract: Currently, stance-control knee orthoses require external control mechanisms to control knee flexion during stance and allow free knee motion during the swing phase of gait. A new angular-velocity control approach that uses a rotary-hydraulic device to resist knee flexion when the knee angular velocity passes a preset threshold is presented. This angular-velocity approach for orthotic stance control is based on the premise that knee-flexion angular velocity during a knee-collapse event, such as a stumble or fall, is greater than that during walking. The new hydraulic knee-flexion control device does not require an external control mechanism to switch from free motion to stance control mode. Functional test results demonstrated that the hydraulic angular-velocity activated knee joint provided free knee motion during walking, engaged upon knee collapse, and supported body weight while the end-user recovered to a safe body position. The joint was tested to 51.6 Nm in single loading tests and passed 200,000 repeated loading cycles with a peak load of 88 Nm per cycle. The hydraulic, angular velocity activation approach has potential to improve safety and security for people with lower extremity weakness or when recovering from joint trauma.
authors.affiliation: Institute for Rehabilitation Research and Development, Ottawa Hospital Rehabilitation Centre, Ottawa, ON, K1H 8M2, Canada. elemaire@ottawahospital.on.ca
authors.forename: Edward D
authors.initials: ED
authors.lastname: Lemaire
authors.forename: Louis
authors.initials: L
authors.lastname: Goudreau
authors.forename: Terris
authors.initials: T
authors.lastname: Yakimovich
authors.forename: Jonathan
authors.initials: J
authors.lastname: Kofman
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D019544:Equipment Failure Analysis; D006801:Humans; D007595:Joint Prosthesis; D008297:Male; D008954:Models, Biological; D009989:Orthotic Devices; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D011474:Prosthesis Design; D012371:Robotics / Q000295:instrumentation* / Q000379:methods; D055815:Young Adult