Exoskeleton

ASB 2024 Recap

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Steele Lab members, Charlotte Caskey, Victoria (Tori) Landrum, and Megan Ebers, attended the American Society of Biomechanics Annual Meeting (ASB) in Madison, WI from August 5-8, 2024.

Charlotte gave a poster presentation on the “Effect of spinal stimulation and interval treadmill training on gait mechanics in children with cerebral palsy”

Tori also gave a poster presentation on the “Impact of a Resistive Exoskeleton on Fatigue in Children with Cerebral Palsy”

Megan co-hosted a Symposia Session titled, “Can machine learning reveal the next generation of neural and biomechanical processes governing human movement?” with Steele Lab Alumni, Michael Rosenberg. In Megan’s talk, “A machine learning approach to quantify individual gait responses to ankle exoskeletons,” she discussed how neural network-based discrepancy modeling can be used to isolate the dynamics governing changes in gait with ankle exoskeletons.

Engineering Discovery Days 2024

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The University of Washington College of Engineering re-launched Engineering Discovery Days this spring. Discovery Days has been a signature outreach event for over 100 years, providing fun and enriching hands-on experiences for students, teachers, and families from across the state. Discovery Days is also an opportunity for our community of UW Engineering students, staff, and faculty to share their passion for engineering with the next generation of innovators.

The UW Biomechanics Faculty put together an exhibit titled “Biomechanics Assemble! From Exoskeletons to Cytoskeletons” with the goal of demonstrating how we study movement and forces in humans and cells at UW.

Two people stand outside, one with a robotic leg, holding a sign reading, "The Human Body: The Ultimate Machine." Both wear "Engineering" shirts. Trees and an event tent are in the background.
A person wearing an exoskeleton suit stands facing a small group of people in a room with various individuals and equipment.
Two people engaged in a discussion while one is wearing a 3D printed prosthetic hand.
Two people fist bumping. One person is wearing a 3D printed prosthetic hand.
A person in a lab wearing an exoskeleton, ready to teach students about biomechanics research.
A woman instructing a child how to use a 3D printed prosthetic hand to pick up a small bottle
A group of students standing around while one is wearing a 3D printed prosthetic hand
A group of students standing around while one is wearing a 3D printed prosthetic hand

The Steele Lab along with the Ingraham Lab hosted two booths. Each booth featured hand-on activities and games for students to engage with.

The first booth features an ensemble of exoskeletons and assistive devices, including the Biomotum Spark and 3D printed prosthetic hands.

The second booth featured two games for students to engage with, including “Myodino” using Delsys EMG sensors, and “UltraLeap Ring Sorting” VR game using the UltraLeap hand tracking technology.

In this lab, we think the human body is “The Ultimate Machine” and we were so excited to share HOW we study the human body at Discovery Days 2024.

A woman showing a young student how to play the game "MyoDino" by activating forearm muscles
A man placing an EMG sensor on the forearm of a young student
A small group of people standing around watching a student play MyoDino on a laptop
A small group of students standing around looking at a laptop as a woman explains how to play the "UltraLeap Ring Sorting"
A small group of students standing a laptop while a student plays the "UltraLeap Ring Sorting"
A small group of students standing a laptop while a person wearing an exoskeleton plays the "UltraLeap Ring Sorting"

Dr. Alyssa Spomer on “Gears of Progress” Podcast

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Gears of Progress Episode 7 featured Alyssa Spomer on biofeedback tech to improve motor control ankle exoskeletons, and work as a clinical scientist at Gillette Children's Hospital.“Gears of Progress” Episode Seven featured Steele Lab Alumni, Dr. Alyssa Spomer on biofeedback tech to improve motor control ankle exoskeletons, and work as a clinical scientist at Gillette Children’s Hospital.

Gears of Progress Logo with three gears featuring assistive devices

Name: Gears of Progress

Platforms: Spotify, Apple Podcasts, Amazon Music, Castbox

Release frequency: bi-weekly on Fridays

Theme: Podcast about research and innovations in rehabilitation engineering and assistive technologies aimed to improve accessibility for people with disabilities. Every episode will feature engineers, medical professionals, end-users, and organizations who focus on improving the health and well-being of individuals with disabilities. We will be covering topics such as emerging tech, outcome measures, medical practice, public policy, accessibility education, and so much more!

Twitter: https://twitter.com/GearsOfProgress

Dr. Kim Ingraham on “Gears of Progress” Podcast

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Gears of progress Episode 5 featured Kim Ingraham. “Gears of Progress” Episode Five featured Steele Lab Alumni, Dr. Kim Ingraham on personalized controllers for lower-limb assistive robotics, powered mobility devices for kids, and a path to a faculty position.

Gears of Progress Logo with three gears featuring assistive devices

Name: Gears of Progress

Platforms: Spotify, Apple Podcasts, Amazon Music, Castbox

Release frequency: bi-weekly on Fridays

Theme: Podcast about research and innovations in rehabilitation engineering and assistive technologies aimed to improve accessibility for people with disabilities. Every episode will feature engineers, medical professionals, end-users, and organizations who focus on improving the health and well-being of individuals with disabilities. We will be covering topics such as emerging tech, outcome measures, medical practice, public policy, accessibility education, and so much more!

Twitter: https://twitter.com/GearsOfProgress

MC Rosenberg, JL Proctor, KM Steele (2024) “Quantifying changes in individual-specific template-based representations of center-of-mass dynamics during walking with ankle exoskeletons using Hybrid-SINDy”

Katie Landwehr JournalArticle, News, Publications , , ,

Journal Article in Scientific Reports

Ankle exoskeletons alter whole-body walking mechanics, energetics, and stability by altering center-of-mass (CoM) motion. Controlling the dynamics governing CoM motion is, therefore, critical for maintaining efficient and stable gait. However, how CoM dynamics change with ankle exoskeletons is unknown, and how to optimally model individual-specific CoM dynamics, especially in individuals with neurological injuries, remains a challenge.

Depictions of walking conditions, phase variables, and example template state variables. (A) Two-dimensional depictions of template model applied to human walking without and with ankle exoskeletons (left). The phase portrait (right) defined a phase variable, , used to cluster kinematically similar measurements for model fitting. Colors denote gait phases corresponding to first and second double-limb support, single-limb support, and swing of the right leg. (B) Stride-averaged global CoM position, velocity, and acceleration for an exemplary unimpaired adult in the anterior–posterior, vertical, and mediolateral directions. The three exoskeleton conditions are shown in panels (B) and (C): shoes-only (solid lines), zero-stiffness exoskeletons (K0; dashed lines), and stiff exoskeletons (KH; dotted lines). (C) Template position and velocity states used to fit the template signatures were defined by sagittal- and frontal-plane leg angles, and leg length.Aim: Evaluate individual-specific changes in CoM dynamics in unimpaired adults and one individual with post-stroke hemiparesis while walking in shoes-only and with zero-stiffness and high-stiffness passive ankle exoskeletons.

Methods: To identify optimal sets of physically interpretable mechanisms describing CoM dynamics, termed template signatures, we leveraged hybrid sparse identification of nonlinear dynamics (Hybrid-SINDy), an equation-free data-driven method for inferring sparse hybrid dynamics from a library of candidate functional forms.

Results: In unimpaired adults, Hybrid-SINDy automatically identified spring-loaded inverted pendulum-like template signatures, which did not change with exoskeletons (p > 0.16), except for small changes in leg resting length (p < 0.001). Conversely, post-stroke paretic-leg rotary stiffness mechanisms increased by 37–50% with zero-stiffness exoskeletons.

Interpretation: While unimpaired CoM dynamics appear robust to passive ankle exoskeletons, how neurological injuries alter exoskeleton impacts on CoM dynamics merits further investigation. Our findings support Hybrid-SINDy’s potential to discover mechanisms describing individual-specific CoM dynamics with assistive devices.