Figure 1

University of Michigan Powered Ankle-Foot Orthosis. Schematic shows signal flow from hand-held pushbuttons activated either by a therapist or by the patient. The pushbuttons generate a real-time voltage proportional to the amount of button press. A computer interface converts this voltage to a control signal (0–10 V). The control signal activates solenoid gated pressure valves that regulate the flow of air into and out of artificial pneumatic muscles on the lightweight carbon fiber ankle-foot orthoses. A 24 year old male (ASIA D) practices walking on a treadmill with partial bodyweight support using the hand-held pushbuttons to command plantar flexor torque assistance at his ankles (right).