Lightweight powered prosthesis - Rehabilitation Institute of Chicago

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Development of a Lightweight Powered Lower-Limb Prosthesis

Project Overview

Project D4

Lightweight motor used to design a lighter prosthesis.

Lightweight, powerful motors such as this one (shown
next to a quarter to illustrate its small size) designed
for a powered upper-limb prosthesis can be used in
development of a compact, lightweight powered leg.

Objective: To develop a lightweight motorized leg and to evaluate this device in elderly persons with transfemoral (above-knee) amputations during various ambulation activities.


Powered lower-limb prostheses offer great promise to the approximately one million Americans with a lower-limb amputation whose ambulation is slower, more asymmetric, less stable, and requires more metabolic energy than that of able-bodied individuals. This is particularly true for older individuals who make up over 90% of persons with a lower-limb amputation in the U.S. and who need assistance simply getting out of chairs, off the toilet, and walking the short distances necessary for them to live independently at home.


Transmissions designed for a
powered upper-limb prosthesis
that can be used in the design
of a lightweight powered leg.

Older individuals, who are generally smaller and weaker, need powered legs that are strong enough to help them get out of a chair, yet light enough to walk with—and to not tip them off balance during swing-phase (when the foot is off the ground).

Current motorized leg prostheses, designed to augment the abilities of younger, healthier users, are not well suited for elderly individuals. They are too heavy for the limited stability and strength of older individuals. Our recent successful design for a lightweight upper-limb prosthesis uses innovative motors and transmissions that have exciting potential for the design of a lightweight lower-limb device.

Target Population

Elderly individuals with a lower-limb amputation. A lightweight powered prosthesis would enable these individuals to maintain independence. Additionally, such a device may also be useful for other smaller individuals, including women and children.

Resources & Statistics


Resources & Organizations

Amputee Coalition

RIC Life Center

UnLIMBited Potential (RIC Support Group)


New Prosthetic Design Focuses on Femininity (O&P Business News, March 2013)

Sensinger JW, Clark SD, and Schorsch JF, "Exterior vs. Interior Rotors in Robotic Brushless Motors," presented at the IEEE Conference on Robotics and Automation, Shanghai, China, 2011.

Sensinger JW and Lipsey JH, "Cycloid vs. Harmonic Drives for use in High Ratio, Single Stage Robotic Transmissions," presented at the IEEE Conference on Robotics and Automation, St. Paul, MN, 2012.



We will update this page periodically with project news and related interviews.


  • Levi Hargrove, PhD, delivered the 2016 Dineen Memorial Lecture at the University of New Brunswick. His speech was titled, "Rewiring Humans: Improving Control of Bionic Limbs." Read an article on Dr. Hargrove's research and listen to a radio interview with him from the Canadian Broadcasting Corporation.
  • Wearable Robotics Association, NIST Workshop 4: Ergonomic issues for Wearable Robotics; speakers included Arun Jayaraman PT, Ph.D., Rehabilitation Institute of Chicago) and "Design Challenges in Interfacing and Controlling Wearable Robots"; speakers included Tommaso Lenzi, PhD, describing aspects of the lightweight leg (Project D4). Scottsdale AZ., February 12, 2016
  • Preliminary results regarding the RIC Hybrid Knee project were presented at the Robotics Science and Systems Conference (RSS 2016) with the workshop titled Assistive Robotic Devices for Dynamic Locomotion; June 18-22 2016, University of Michigan


  • Lenzi T., Sensinger JW, Lipsey J, Hargrove L, Kuiken TA. (Poster presentation) The RIC hybrid knee prosthesis” IEEE International Conference on Robotics and Automation (ICRA, 2015),May 26-30, 2015, Seattle, WA
  • Lenzi T, Sensinger JW, Lipsey J, Hargrove LJ, Kuiken TA Design and Preliminary Testing of the RIC Hybrid Knee Prosthesis; 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, August 25-29 2015, Milan, Italy


Project Staff

Todd Kuiken, MD, PhDTodd A. Kuiken
, MD, PhD, Principal Investigator. Dr. Kuiken is director of the Center for Bionic Medicine (CBM) within the Rehabilitation Institute of Chicago. At CBM, Dr. Kuiken leads an interdisciplinary team that includes physicians, prosthetists, therapists, neuroscientists, engineers, software developers, graduate students, and post-doctoral researchers. He received his BS in biomedical engineering from Duke University, and his MD and PhD degrees from Northwestern University.

Jim LipseyJim Lipsey, MS, PE, Engineering Project Leader. Mr. Lipsey is an engineering manager at the Center for Bionic Medicine. As engineering manager, he is responsible for long-term planning and day-to-day execution in developing complex electromechanical systems; hiring and managing team members; defining internal processes; and technical mentoring. He received his BE and MS degrees in mechanical engineering from Vanderbilt University.

Jon SensingerJon Sensinger, PhD, Collaborator. Formerly with the Center for Bionic Medicine, Dr. Sensinger is currently Associate Director of the Institute of Biomedical Engineering at the University of New Brunswick. His research interests include body-powered and robotic prosthesis design and control, with a specific interest in developing-world applications. He focuses on clinically relevant, low cost/weight systems. Dr. Sensinger received his PhD in biomedical engineering from Northwestern University.

Additional staff members: Tommaso Lenzi, PhD; Tom Pickerill, BSME; Tom Sharkey, BSME

Project Alumni: Jeremy Newkirk, PhD

The contents of this website were developed under a grant from the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR grant number 90RE5014-02-00). NIDILRR is a Center within the Administration for Community Living (ACL), Department of Health and Human Services (HHS). The contents of this website do not necessarily represent the policy of NIDILRR, ACL, HHS, and you should not assume endorsement by the Federal Government.