# Enhancing Voluntary Motion in Broad Patient Populations with Modular Powered Orthoses

> **NIH NIH R01** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2021 · $1,767,419

## Abstract

PROJECT ABSTRACT
The overall goal of this project is to develop modular, lower-limb, powered orthoses that fit to user-specific
weakened joints and control force/torque in a manner that enhances voluntary motion in broad patient
populations. Conventional orthoses tend to immobilize joints, and emerging powered orthoses constrain
voluntary motion by using highly geared electric motors and/or control methods that force the user to follow a
specific gait pattern. Consequently, these devices have not seen widespread success across populations with
weakened voluntary control due to stroke, advanced age, or musculoskeletal disorders. These heterogeneous
populations require partial, not full, assistance of user-specific muscle groups during daily activities. However,
there is a fundamental gap in knowledge about how to design and control powered orthoses to assist the user
without constraining their motion. The central hypothesis of this project is that high-torque, low-inertia motor
systems controlled with energetic objectives will enable modular powered orthoses to partially assist the joints.
High-torque electric motors combined with minimal transmissions can be freely rotated (i.e., backdriven) by
human joints, allowing the use of an emerging torque control method called energy shaping to reduce the
perceived weight/inertia of the body during any motion. By mounting these modular actuators to commercial
orthoses, this technology will be easily prescribed/configured by clinicians. The project aims are as follows:
Aim 1: Develop design paradigm to enable backdrivable, modular powered orthoses.
Hypothesis: A torque-dense “pancake” motor with a low gear ratio will provide high output torque, low backdrive
torque, low acoustic noise, and energy efficiency in lightweight, powered orthosis joint modules.
Aim 2: Develop torque control paradigm to facilitate voluntary motion assistance in orthoses.
Hypothesis: Modular joint configurations of partial-assist orthoses will provide torque assistance by selectively
offloading mass and inertia in the human body through energy shaping.
Aim 3: Establish feasibility of assisting different populations with modular powered orthoses.
Hypothesis: Assisting lower-limb musculature with modular powered orthoses will improve functional outcomes
in subjects with chronic stroke or sarcopenia, and improve lifting/lowering posture in able-bodied subjects.
 This project will be technologically significant to the design of modular powered orthoses for enhancing
voluntary motion, scientifically significant to understanding how to control body energetics to partially assist
different joints in a task-invariant manner, and clinically significant to the widespread adoption of powered
orthoses to restore mobility in broad populations with weakened voluntary control. The flexible assistance
offered by this modular orthosis technology will have a profound impact on mobility and quality of life for tens
of millions of Americans, as nearly...

## Key facts

- **NIH application ID:** 10190208
- **Project number:** 1R01EB031166-01
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Robert D Gregg
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $1,767,419
- **Award type:** 1
- **Project period:** 2021-09-22 → 2026-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10190208

## Citation

> US National Institutes of Health, RePORTER application 10190208, Enhancing Voluntary Motion in Broad Patient Populations with Modular Powered Orthoses (1R01EB031166-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10190208. Licensed CC0.

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