Fig. 1

System overview (a) Picture of a person wearing an ankle-foot orthosis (AFO) with a backpack. (b) The backpack, as a pneumatic power source, comprises a compressor, battery, master board, and both inlet/outlet fans for heat dissipation. (c) The AFO consists of a pneumatic actuator, frame for fixation, and an insole. An air tube is connected between the compressor and pneumatic cylinder. Two ground reaction force (GRF) sensors are located on the toe and heel for gait phase detection. Calf braces placed in the top and the middle of the frame connect the AFO with the human leg and contribute to the high force transmissibility via a stable fixation of the static part of the pneumatic cylinder to the calf. The dial, including the laces in the brace, enables the adjustment of the fixation of the AFO frame to the calf. Supply and discharge solenoid valves are implemented for AFO control based on the GRF sensor signal