Exoskeleton

Engineering Discovery Days 2024

Katie Landwehr News, Outreach , , , ,

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

Katie Landwehr Media, News , , , ,

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

Katie Landwehr Media, News , ,

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.

AM Spomer, BC Conner, MH Schwartz, ZF Lerner, KM Steele (2023) “Audiovisual biofeedback amplifies plantarflexor adaptation during walking among children with cerebral palsy”

Katie Landwehr JournalArticle, MotorControl, News, Publications , , , , , ,

Journal Article in Journal of NeuroEngineering and Rehabilitation

Biofeedback is a promising noninvasive strategy to enhance gait training among individuals with cerebral palsy (CP). Commonly, biofeedback systems are designed to guide movement correction using audio, visual, or sensorimotor (i.e., tactile or proprioceptive) cues, each of which has demonstrated measurable success in CP.

Figure 1. Experimental Protocol. Audiovisual (AV) biofeedback on soleus activity was provided for the more-affected limb alongside an auto-adjusting target score. Sensorimotor (SM) biofeedback was provided for the more-affected limb using an untethered ankle exoskeleton designed to impart a resistive ankle torque through stance, proportional to baseline values. Participants completed three data collection visits (pre-acclimation, post-acclimation, and follow-up), during which they walked with both biofeedback systems independently and in combination. Trials were pseudo-randomized within and between visits to ensure that feedback modalities were presented to each participant in a different order and control for fatigue and learning effects. Each trial was 10 min long and separated into baseline, feedback, and washout phases. All data analysis was performed for early (strides 1–30), mid (strides 91–110), and late (strides 181–210) feedback phases and washout (strides 1–30). Mean soleus activity for individual strides (purple dots) was normalized to baseline activity. Between the pre-acclimation and post-acclimation visits, participants completed four, 20-min acclimation sessions where they received additional practice with both systems

Aim: The aim of this study is to evaluate how the modality of biofeedback may influence user response which has significant implications if systems are to be consistently adopted into clinical care.

Method: In this study, we evaluated the extent to which adolescents with CP (7M/1F; 14 [12.5,15.5] years) adapted their gait patterns during treadmill walking (6 min/modality) with audiovisual (AV), sensorimotor (SM), and combined AV + SM biofeedback before and after four acclimation sessions (20 min/session) and at a two-week follow-up. Both biofeedback systems were designed to target plantarflexor activity on the more-affected limb, as these muscles are commonly impaired in CP and impact walking function. SM biofeedback was administered using a resistive ankle exoskeleton and AV biofeedback displayed soleus activity from electromyography recordings during gait. At every visit, we measured the time-course response to each biofeedback modality to understand how the rate and magnitude of gait adaptation differed between modalities and following acclimation.

Results: Participants significantly increased soleus activity from baseline using AV + SM (42.8% [15.1, 59.6]), AV (28.5% [19.2, 58.5]), and SM (10.3% [3.2, 15.2]) biofeedback, but the rate of soleus adaptation was faster using AV + SM biofeedback than either modality alone. Further, SM-only biofeedback produced small initial increases in plantarflexor activity, but these responses were transient within and across sessions (p > 0.11). Following multi-session acclimation and at the two-week follow-up, responses to AV and AV + SM biofeedback were maintained.

Interpretation: This study demonstrated that AV biofeedback was critical to increase plantarflexor engagement during walking, but that combining AV and SM modalities further amplified the rate of gait adaptation. Beyond improving our understanding of how individuals may differentially prioritize distinct forms of afferent information, outcomes from this study may inform the design and selection of biofeedback systems for use in clinical care.