Exoskeletons for Augmenting Human Performance

From clinical injury rehabilitation to outdoor heavy-duty manual labor, exoskeleton technology holds great promise in extending human capability and augmenting performance. IHMC has over a decade of experience researching mobility-restoring exoskeletons showcased by the 2016 and 2020 Cybathlon competitions and Toyota Mobility Foundation Mobility Unlimited Challenge with the Mina and Quix devices. In recent years, IHMC is focused on developing new ability-augmenting exoskeletons for use in radioactive waste cleanup.

Eva Exoskeleton

Eva (pictured above is a powered lower-body exoskeleton that is being developed by IHMC to offload the weight of heavy personal-protective equipment from users’ bodies to the ground while also augmenting user motion. The suit is designed to assist throughout the users’ natural range of motion so as to not restrict movements.

The suit provides net positive power to hip and knee flexion/extension as well as ankle plantarflexion while passively allowing motion in other degrees of freedom of the hips. The hips and knees are driven by collocated brushless DC motor actuators, while the ankles are driven by cables attached to actuators located in the backpack. Also within the backpack is a custom power system, which enables battery-powered operation as well as charge monitoring. Outside of the backpack, an SCBA tank can be mounted using a custom harness, allowing for direct integration with common nuclear site PPE.

Eva is also features a wide array of adjustable features (i.e. length adjustable thighs and shanks, depth and width adjustable leg interfaces, height adjustable torso brace and backpack straps, size adjustable foot attachments) and can fit a wide range of body types.

Assisting Numerous Tasks

Eva utilizes an inverse-dynamics-based gravity compensation control to offload the weight of itself and added PPE regardless of body position. It calculates the static torques required to resist both the gravitational forces on each link and the ground reaction forces being imparted on the feet. The control algorithm uses information about the exoskeleton’s mass, inertia, and geometry as well as the centers of pressure and force distribution of the user’s feet sensed by pressure sensitive insoles in the user’s shoes. A custom on-board user interface (UI) allows the wearer to control the device from startup to shutdown, allowing for direct modulation of gravity compensation.

Along with gravity compensation, we have developed task-specific controllers aimed at assisting common manual labor movements (e.g. squatting/lifting, pushing/pulling, walking) as well as a machine-learning based task classifier to identify movement types and transition between controllers.

The overall goal of Eva, as well as future exoskeleton projects, is to develop useful devices that have direct real-world application. We hope that this work will lead to injury risk reduction across industries, so that workers can complete their jobs knowing that they aren’t taking the job home with them.