Development of a Powered Exoskeleton Device for Lower Limb Assistance

Assistive Hip Exoskeleton Study

Sponsors

Lead sponsor: Georgia Institute of Technology

Source Georgia Institute of Technology
Brief Summary

The increased metabolic and biomechanical demands of ambulation limit community mobility in persons with lower limb disability due to neurological damage. There is a critical need for improving the locomotion capabilities of individuals who have walking impairments due to disease to increase their community mobility, independence, and health. Robotic exoskeletons have the potential to assist these individuals by increasing community mobility to improve quality of life. While these devices have incredible potential, current technology does not support dynamic movements common with locomotion such as transitioning between different gaits and supporting a wide variety of walking speeds. One significant challenge in achieving community ambulation with exoskeletons is providing an adaptive control system to accomplish a wide variety of locomotor tasks. Many exoskeletons today are developed without a detailed understanding of the effect of the device on the human musculoskeletal system. This research is interested in studying the question of how the control system affects human biomechanics including kinematic, kinetics and muscle activation patterns. By optimizing exoskeleton controllers based on human biomechanics and adapting control based on task, the biggest benefit to patient populations will be achieved to help advance the state-of-the-art with assistive hip exoskeletons.

Detailed Description

One significant challenge in achieving community ambulation with exoskeletons is providing an adaptive control system to accomplish a wide variety of locomotor tasks. Many exoskeletons today are developed without a detailed understanding of the effect of the device on the human musculoskeletal system. The study is interested in exploring the question of how the control system affects human biomechanics including kinematic, kinetics and muscle activation patterns. By optimizing exoskeleton controllers based on human biomechanics and adapting control based on task, this work will be able to provide the biggest benefit to patients and advance the state-of-the-art with assistive hip exoskeletons. A large patient population that could benefit from lower limb assistive technology are stroke survivors, which is the specific population this proposal targets. One common characteristic of stroke survivors who regain their ability to walk is that the hip muscles are overtaxed due to distal weakness. The investigators propose to use a powered hip exoskeleton to augment their proximal musculature, which needs to produce significant power output in most locomotion activities such as standing up, walking, and going up stairs or slopes. Another biomechanical aspect of stroke survivors is an asymmetric gait in terms of kinematics, kinetics and muscle activations. The research team will examine what kind of exoskeleton assistance is most beneficial to stroke survivors for enhancing community ambulation. The hypothesis is that since the gait is asymmetric, the controller will need to be asymmetric to provide optimal assistance to aid in mobility. The group's long-term research goal is to create powered assistive exoskeletons devices that are of great value to individuals with serious lower limb disabilities by improving clinical outcomes such as walking speed and community ambulation ability. The overall objective of the proposed project is to study the biomechanical effects of using a hip exoskeleton with adaptive controllers for assisting stroke survivors with lower limb deficits to improve their community ambulation capabilities. The central hypothesis overarching both aims is that exoskeleton control that adapts to environmental terrain will improve mobility metrics for human exoskeleton users on community ambulation tasks. The rationale is that since human biomechanics change based on task, exoskeleton controllers likewise need to optimize their assistance levels to match what the human is doing. The first aim of the proposed study is to determine the benefit of exoskeleton control that adapts to the environment for improving community ambulation capability. The team has previously designed and extensively tested an autonomous hip exoskeleton in able-bodied subjects on a treadmill. The investigators plan to extend their control framework to over ground walking and tune assistance magnitude and timing levels to enable efficient locomotion over stairs and ramps on their novel terrain park. The investigators plan to compare a controller that adapts its assistance strategy based on locomotion task to a static controller as well as not wearing the exoskeleton. The primary hypothesis for this aim is that exoskeleton control that adapts to environmental terrain will improve mobility metrics such as task completion speed for human exoskeleton users on community ambulation tasks. The expected outcome of these aims will be an increased understanding of the biomechanical and clinical effects in applying hip assistance with a robotic exoskeleton in community ambulation tasks such as overground walking, ramps and stairs. This work will serve as a foundational start for a broader planned study of optimizing controllers to improve biomechanics in the walking impaired using powered hip autonomous exoskeletons.

Overall Status Recruiting
Start Date August 14, 2019
Completion Date April 30, 2022
Primary Completion Date December 31, 2020
Phase N/A
Study Type Interventional
Primary Outcome
Measure Time Frame
Walking Speed 18 months
Enrollment 10
Condition
Intervention

Intervention type: Device

Intervention name: Powered hip exoskeleton

Description: The study team will test a powered hip exoskeleton and its capability to improve locomotion.

Arm group label: Healthy individuals using powered exoskeleton

Eligibility

Criteria:

Inclusion Criteria:

- Between 18-85 years of age

- Subjects should be capable of walking, ascending/descending stairs and ramps with full capability in lower extremity passive range of motion (knee flexion contracture of >10 degrees, knee flexion ROM < 90 degrees, hip flexion contracture < 25 degrees, and ankle plantar flexion contracture of >15 degrees).

- Subjects must be able to walk for at least 5 minutes and willing and able to participate over a 1-6 hours experiment with breaks and rest enforced regularly and as needed.

- Subjects must be able to transfer (sit-to-stand and stand-to-sit) with no external support (arm rests OK) and to ambulate over small slopes (3 degrees) and a few steps (6 steps).

Exclusion Criteria:

- History of neurological injury, gait pathology, or cardiovascular condition that would limit your ability to ambulate for multiple hours.

Gender: All

Minimum age: 18 Years

Maximum age: 85 Years

Healthy volunteers: Accepts Healthy Volunteers

Overall Official
Last Name Role Affiliation
Aaron Young, Ph.D. Principal Investigator Georgia Tech
Overall Contact

Last name: Aaron Young, Ph.D.

Phone: 404-385-5306

Email: [email protected]

Location
facility status contact investigator Exoskeleton and Prosthetic Intelligent Controls Lab Aaron Young, Ph.D. 404-385-5306 aaron.youn[email protected] Aaron Young, Ph.D. Principal Investigator
Location Countries

United States

Verification Date

August 2019

Responsible Party

Responsible party type: Sponsor

Keywords
Has Expanded Access No
Condition Browse
Number Of Arms 1
Arm Group

Arm group label: Healthy individuals using powered exoskeleton

Arm group type: Experimental

Description: This study will be conducted on a sample population of able-bodied subjects (single arm). Each subject will test with each condition of the exoskeleton (repeated measures).

Patient Data No
Study Design Info

Allocation: N/A

Intervention model: Single Group Assignment

Intervention model description: The model used is a repeated measures single arm study. Multiple conditions including using and not using the device will be tested on the same subjects to have multiple test points on a per subject basis.

Primary purpose: Basic Science

Masking: None (Open Label)

Source: ClinicalTrials.gov