2025-02-26: Control, Characterization, and Validation of the Efficient Lockable Spring Ankle (ELSA) Prosthesis by Jeanne Evard

The majority of ankle prostheses available today are passive, lacking the net positive energy output of biological ankles, which tends to lead to asymmetric gait and related health issues. Recent advancements in powered prostheses tend to mimic ankle joint behavior, but design constraints like weight, size, and energy efficiency, along with challenges in performance evaluation and control development, remain significant.  

This research focuses on the ELSA prosthesis, a compact and lightweight powered ankle. The first objective of this thesis was to characterize the device specifically examining its power, torque, energy efficiency, and related metrics. Next aims focused on developing and validating a high-level controller for autonomous task detection, as well as evaluating the device versatility across various functions. To accomplish these objectives, we carried out both bench validation and experimental trials with prosthesis users, testing ELSA under a range of conditions.

Overall, this thesis underscores ELSA's potential to replicate ankle dynamics, providing control strategies for daily life adaptability, while identifying areas for improvement and future development.