A Universal Ankle–Foot Prosthesis Emulator for Human Locomotion Experiments

Robotic prostheses have the potential to significantly improve mo-bility for people with lower-limb amputation. Humans exhibit com-plex responses to mechanical interactions with these devices, however, and computational models are not yet able to predict such responses meaningfully. Experiments therefore play a critical role in development, but have been limited by the use of product-like prototypes, each requiring years of development and special-ized for a narrow range of functions. Here we describe a robotic ankle–foot prosthesis system that enables rapid exploration of a wide range of dynamical behaviors in experiments with human sub-jects. This emulator comprises powerful off-board motor and con-trol hardware, a flexible Bowden cable tether, and a lightweight instrumented prosthesis, resulting in a combination of low mass worn by the human (0.96 kg) and high mechatronic performance compared to prior platforms. Benchtop tests demonstrated closed