Hotcell Worker Assistive Robotic Exoskeleton Design and Control

A US Department of Energy (DOE) sponsored study conducted by the Los Alamos National Laboratory reported the incidence rate of repetitive stress injuries increased from 22% after 1–2 hours of work to 50% after 3 hours of work per day due to fatigue, repetitive motion, and hyperextension during manipulation tasks in glovebox and hotcell workspaces at DOE facilities [1, 2]. Because of the repetitive nature of the tasks in these facilities, a proposed exoskeleton assistive device is being developed to help reduce worker fatigue and therefore, reduce fatigue and stress related injuries. Current stages of this project focus on the design and development of an upper limb assistance exoskeleton device which aims to reduce worker fatigue through muscular involvement minimization. The design includes a low-profile frame which houses various radially guided joints which parallel human arm movement directions to allow for an ergonomic natural movement. Active assistance is seen in a vertical manner to help reduce muscleA fatigue stemming from carrying materials, as well as maintaining the weight of the worker's arm and whichever tools they may be carrying to complete the task. This work outlines the development of the mechanical and software-based control aspects of the assistive device, as well as an overall view of the many limitations which must be taken into consideration during the design and development.