Comparison of Balance Recovery Among Current Control Strategies for Robotic Leg Prostheses

Over the past two decades, a number of control strategies have been developed for powered transfemoral prostheses. These strategies have in common that they help restore gait in amputee locomotion. However, it remains unclear how well they support balance recovery after disturbances. Here, we first present a comparison of balance recovery performance among current controls for powered transfemoral when their users are subjected to unexpected ground slips. While some controls perform better than others in this comparison, they all suffer from a limited awareness of both the environment and the user’s intent, which inevitably leads to catastrophic failures and eventual falls. We then introduce our current efforts toward more interactive prosthesis controls that continuously adapt to changes in the environment and user intent. In initial work, we find that such continuous adaptations substantially improve gait robustness, encouraging a more aggressive research agenda toward real-time reactive leg prosthesis controls.