Continuous Inter-Leg Transitions Between Walking and Stair Ascent/Descent with a Powered Prosthesis
Although powered prosthetic legs have enabled more biomimetic joint kinematics during steady-state activities like walking and stair climbing, transitions between these activities are usually handled by discretely switching controllers without considering biomimicry or the distinct role of the leading leg. This video shows two data-driven, phase-based kinematic control approaches for seamless inter-leg transitions (i.e., initiated by either the prosthetic or intact leg) between walking and stair ascent/descent, assuming high-level knowledge of the upcoming activity. One approach employs a novel continuously-varying kinematic model that interpolates between steady-state activities as an approximate convex combination, and the other approach employs a simple switching-based model with optimized switching timing and tunable smoothing of kinematic discontinuities. Experimental validation with a powered knee-ankle prosthesis used by two high-functioning transfemoral amputee participants demonstrates the continuous controller can provide more biomimetic and uninterrupted kinematic trajectories for both joints during transitions, irrespective of the initiating leg. This research underscores the potential for enabling more natural locomotion for high-functioning prosthetic leg users.
This video is supplemental multimedia for the article:
S. Cheng, C. Laubscher, and R. Gregg, “Controlling Powered Prosthesis Kinematics over Continuous Inter-Leg Transitions Between Walking and Stair Ascent/Descent,” IEEE Trans Neural Systems Rehab Eng, 2024.
This work was supported by the National Institutes of Health.