Patent ID: 8403997

Claim:
A self-teaching lower limb prosthesis for an above-knee amputee, the prosthesis comprising: an upper limb portion and a lower limb portion connected to each other by a knee joint that allows flexion and extension of the limb portions relative to each other; and a dynamically adjustable knee movement control unit arranged to control flexion and/or extension movements of the knee joint of the prosthesis so as to adjust the rate at which the knee joint swings, wherein the control unit comprises: an electronic storage device storing a target relationship between walking speed and a parameter that is a ratio of (i) a flexed state duration of an amputee's gait during use of the prosthesis to (ii) one of an extended state duration and a total cycle period of the amputee's gait during use of the prosthesis, the relationship defining a plurality of values of the parameter associated with different respective walking speeds, a monitoring system comprising a sensor arranged to sense flexion and extension movements of the knee joint and a processor that receives signals from the sensor and processes the signals to generate monitoring signals representative of walking speed values and values of the parameter occurring during use of the prosthesis at different walking speeds, and an adjustment system arranged to adjust the control unit automatically in response to said monitoring signals indicating deviation of the parameter from the target relationship, such that: when the parameter is below the target relationship at a given walking speed the adjustment system adjusts the control unit to reduce the rate at which the knee joint swings; and when the parameter is above the target relationship at a given walking speed the adjustment system adjusts the control unit to increase the rate at which the knee joint swings.