Auto-Adjusting Transtibial Prosthetic Socket
A second-generation auto-adjusting prosthetic socket for people with transtibial amputation. Three motor-driven panels continuously maintain prosthetic fit by detecting and responding to residual limb volume changes throughout the day.
Overview
The Problem
Residual limb volume fluctuates continuously throughout the day, causing prosthetic sockets to fit poorly over time. The consequences are pervasive: pain, skin breakdown, instability, and often prosthesis abandonment altogether. The traditional fix is manually adding or removing prosthetic socks, which is imprecise, disruptive, and socially awkward.
The Solution
ADAPT 2 uses inductive distance sensors embedded in the socket wall to continuously detect limb-to-socket clearance. A microcontroller interprets this data and drives three motor-actuated panels (two anterior, one posterior) to expand or contract as needed. Adjustments are gradual enough that users typically do not notice them, yet effective enough to maintain fit across an entire day of varied activity.
Key Outcomes
- ●Auto-adjusting fit during walking validated in peer-reviewed studies; 13-participant take-home study completed
- ●Extended controller coverage toward the full range of daily activities beyond walking
My Role
Research Engineer II
(Assembly, Controls Development & Human Subjects Testing)
Impact & Results
ADAPT 2 builds on a validated research program that has demonstrated automatic prosthetic fit management during walking in peer-reviewed research and real-world take-home studies. My work extended that capability toward the full range of daily activity, targeting the ~90–95% of wear time that existing systems do not adequately address.
Clinical Reach
13-participant take-home study completed, validating auto-adjusting fit during real-world daily use
Patent Portfolio
Named inventor on multiple pending patent applications (University of Washington, filed 2024–2025)
Extended Coverage
Advanced auto-adjustment from walking toward the full range of daily activities: sitting, standing, transitioning, and weight-shifting
Key Takeaways
- ●End-to-end ownership of a complex embedded medical device: assembly, firmware, testing, and analysis
- ●Developing control systems that must generalize across diverse users, activity profiles, and real-world conditions
- ●Translating participant feedback and sensor data into concrete hardware and software improvements across iterations
- ●Running take-home studies that expose failure modes and usability gaps invisible in lab-controlled testing
Skills Developed
Research & Publications
The following papers document the research program that ADAPT 2 builds on. I joined after these specific studies were completed; my work directly extended and advanced these findings.
Sanders JE, Vamos AC, Mertens JC, et al. “An adaptive prosthetic socket for people with transtibial amputation.” Scientific Reports 2024; 14: 11168.DOI: 10.1038/s41598-024-61234-9
Weathersby EJ, Vamos AC, Larsen BG, et al. “Performance of an auto-adjusting prosthetic socket during walking with intermittent socket release.” J Rehabil Assist Technol Eng 2022; 9.
Weathersby EJ, Garbini JL, Larsen BG, et al. “Automatic control of prosthetic socket size for people with transtibial amputation: Implementation and evaluation.” IEEE Trans Biomed Eng 2021; 68(1): 36–46.
Mertens JC, Price CA, Baumann ME, et al. “Testing an adjustable prosthetic socket in a simulated military environment.” J Rehabil Assist Technol Eng 2025.
Named inventor on multiple pending patent applications (University of Washington). Applications filed 2024–2025 are not yet publicly available — the USPTO typically publishes ~18 months after filing. An earlier related application is publicly available: US20200345520 — "Motorized Adjustable Socket For Amputee Prosthesis Users And Methods For Use Thereof" — Sanders JE et al.
Interested in working together?