Case Study: ESTAT’s LEET Protects Fighter Pilots
Light-weight
Electroadhesive
Exo
Tendon System
Introduction
Introducing ESTAT’s Lighweight Electroadhesive ExoTendon System (LEET). ESTAT is proud to serve our US Air Force through the development of ExoTendon systems for injury prevention. This project started as an SBIR supporting Fighter Pilots and is expanding to include Boom Operators serving in our KC-135 Fleet.
The Problem
Head mounted equipment provides a significant tactical advantage, but shifts the center of mass of the head up and forward. This puts strain on neck muscles, increases stress in the joints of the neck, and puts the pilot at particularly high injury risk during ejection events.
The Air Force currently has 1900 empty pilot positions as a direct result of neck pain. In fact, 92% of pilots experience chronic pain and injury. This issue directly impedes the Air Force’s Readiness to Deploy and Fight.
ESTAT technology presents a promising opportunity to address this problem.
The Solution
The LEET-F is designed for Fighter pilots. It reduces neck fatigue, improves performance, and protects the neck at High G.
How it Works
System Overview
The LEET is enabled by our unique electroadhesive clutches. With the flexibility to be mounted anywhere on the body, a spring-based mechanism provides the right force to counterbalance the weight of head mounted equipment without adding weight to the helmet. Forces from this counterbalance mechanism are transmitted around the body using a flexible transmission called a Bowden cable. The pilot experiences the LEET as a force tugging up on their parachute harness and down on the back of the helmet. The system is capable of transitioning seamlessly between modes to provide the right kind of protection at the right time.
Smart Mode Switching
The LEET can automatically sense the need to transition between three operating modes: Support, Protect, and Transparent. In Support mode, the LEET acts as a spring to counterbalance the weight of helmet mounted equipment. In Protect mode, the LEET senses a high G event such as ejection and locks the tether to hold the head in place. This redirects forces from the head to the body and protects the neck. This is very similar to the way guy wires on cell towers redirect wind forces to the ground. Lastly, the LEET can enter Transparent mode in which the tethers go slack and the pilot is free to move their head as if they were wearing nothing at all. This enables them to perform to their maximum capability.
It is this ability to transition between modes with an incredibly lightweight, compact and power efficient system that sets the LEET apart from all other exoskeleton technologies. The system is passive and contains no motors, AND IS SMART.
Simulation Results
The LEET reduces force in the neck muscles and restrains the head to prevent whiplash during ejection.
ESTAT has partnered with Dr. Jeff Reinbolt and Dr. Anita Vasavada to produce an OpenSim model of the LEET-F system, which demonstrates improvements in injury risk for pilots of all sizes in multiple high G scenarios. According to their simulation results, the LEET-F reduces injury risk by as much as 95% during ejection.
The Ejection Scenario
During the catapult phase of ejection, the pilot can experience 12-15Gs of vertical acceleration. The head whips forward during the catapult phase, rebounds and then is subject to wind blast when they clear the cockpit which causes further whiplash. The LEET senses ejection and locks the tethers to stabilize the head during this violent event.
How it Works
The Future of the LEET-F
ESTAT is finishing the design of the LEET-F 2.0 which will feature multiple tethers and dramatically reduced size. This system will be subjected to mil-spec testing in Summer 2024.
Manikin testing will be performed at the 711th Human Performance Wing at Wright Patterson Air Force Base in Winter 2024. This testing will include the Vertical Deceleration Tower (right) which will subject the system to the accelerations experienced during ejection.
Dr. Kirby Witte, VP of Engineering, and Dr. Ben Shafer, Post-Doctoral Research Engineer, visit Wright Patterson Air Force Base to plan for manikin testing on the Vertical Deceleration Tower.
Dr. Ben Shafer, ESTAT’s resident kinesiologist and Research Engineer, experiences what it is like to be a Boom Operator inside the Boom Operator Simulator System (BOSS) at the 171st Refueling Wing with the help of Boom Operator and Trainer, Randy Reese.
The Future of ESTAT’s LEET Product Line
ESTAT plans to extend LEET protection to other members of the Air Force, specifically Boom operators on the KC-135. Boom operators have to maintain an extreme posture (see left) for hours on end. Using their neck muscles to support the weight of their heads for such long periods of time is severely taxing. This is another great application for ESTAT’s LEET.
We are excited to be working with Justin Jones, Innovation Officer at the 171st Refueling Wing, to promote a proposed LEET for Boom Operators, the LEET-B. We are also grateful for the support of Wing Commander Col. Hyland and are excited to be supporting our local Pittsburgh-based Air National Guard.
Reach Out
ESTAT is interested in learning more about careers with unique musculoskeletal risks. If you have a potential application for LEET technology and would like to discuss, let us know!