# Intuitive Control of a Hybrid Prosthetic Leg During Ambulation

> **NIH NIH R01** · REHABILITATION INSTITUTE OF CHICAGO D/B/A SHIRLEY RYAN ABILITYLAB · 2020 · $603,828

## Abstract

Project Summary/Abstract
Most individuals with lower limb amputations use passive prostheses, which do not provide energy to assist with
activities such as stair or ramp ascent or sit-to-stand transitions. This limits mobility, in particular for those with
above-knee amputations. Powered leg prostheses could improve the mobility and community participation of
such individuals; however, these devices are heavy, and current control systems require the user to manually
transition between different ambulation activities, which is cumbersome. With prior R01 funding, we developed
an adaptive, hierarchical pattern recognition control system that uses data from sensors on the prosthesis, and
incorporates electromyographic (EMG) signals from the user, depending on their reliability, to determine user
intent and enable safe prosthesis control with automatic, seamless transitions between ambulation activities. A
mobile application allows for rapid tuning of the prosthesis and enables the user to choose between manual or
automatic transitions. With other funding, we developed a novel prosthetic leg that can operate in passive mode
—during level-ground walking or in active mode—during activities such as stair climbing or sit-to-stand
transitions. This approach enables smaller, lighter motors, transmissions, and batteries, making our Hybrid Leg
significantly lighter and quieter than other powered devices. Our long-term objective is to develop clinically viable
technologies to improve the quality of life for lower limb amputees. A lightweight powered prosthesis with a safe,
intuitive control system may increase mobility—facilitating employment, leisure, and community participation
activities—and reduce the physical and psychological consequences of low activity. We will compare the Hybrid
Leg with subjects' passive devices in both in-lab and home environments. In Aim 1, we will transition our adaptive
control system to the Hybrid Leg, train users to walk with this device while the experimenter manually transitions
the device between activity modes, and collect sensor data and EMG signals to create a user-specific pattern
recognition control system. We will then determine the classification accuracy of this system. Aims 2 and 3
together constitute a randomized clinical trial, with AB-BA design, comparing the Hybrid leg with subjects' own
passive devices. In Aim 2, we will provide advanced community-mobility training for either the subject's passive
leg or the Hybrid leg, in random order, to meet both subject-specific and general activity goals necessary for
community ambulation, and complete a full biomechanical assessment of ambulation activities such as stair or
ramp ascent/descent and sit-to-stand transitions with that leg. In Aim 3, subjects will use the same leg for 4
weeks in their home and community, where activity and community participation will be monitored by a custom
smartphone–based app. We will compare the number of steps taken and number of transi...

## Key facts

- **NIH application ID:** 9987337
- **Project number:** 5R01HD079428-07
- **Recipient organization:** REHABILITATION INSTITUTE OF CHICAGO D/B/A SHIRLEY RYAN ABILITYLAB
- **Principal Investigator:** Levi John Hargrove
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $603,828
- **Award type:** 5
- **Project period:** 2014-09-06 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9987337

## Citation

> US National Institutes of Health, RePORTER application 9987337, Intuitive Control of a Hybrid Prosthetic Leg During Ambulation (5R01HD079428-07). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9987337. Licensed CC0.

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