title: EMG control of a bionic knee prosthesis: exploiting muscle co-contractions for improved locomotor function.
abstract: This paper presents the development and experimental evaluation of a volitional control architecture for a powered-knee transfemoral prosthesis that affords the amputee user with direct control of knee impedance using measured electromyogram (EMG) potentials of antagonist muscles in the residual limb. The control methodology incorporates a calibration procedure performed with each donning of the prosthesis that characterizes the co-contraction levels as the user performs volitional phantom-knee flexor and extensor contractions. The performance envelope for EMG control of impedance is then automatically shaped based on the flexor and extensor calibration datasets. The result is a control architecture that is optimized to the user's current co-contraction activity, providing performance robustness to variation in sensor placement or physiological changes in the residual-limb musculature. Experimental results with a single unilateral transfemoral amputee user demonstrate consistent and repeatable control performance for level walking at self-selected speed over a multi-week, multi-session period of evaluation.
authors.forename: James A
authors.initials: JA
authors.lastname: Dawley
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Fite
authors.forename: George D
authors.initials: GD
authors.lastname: Fulk
mesh_terms: D001186:Artificial Limbs; D001696:Biomechanical Phenomena; D001701:Bionics / Q000295:instrumentation; D004576:Electromyography / Q000379:methods*; D006801:Humans; D007717:Knee / Q000503:physiopathology; D007719:Knee Joint / Q000502:physiology; D007720:Knee Prosthesis; D007866:Leg / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D016138:Walking / Q000502:physiology*