Design of a Fail-Safe Wearable Robot with Novel Extendable Arms for Ergonomic Accommodation during Floor Work

Abstract

Aircraft manufacturing, construction, and agricultural production often involve workers maintaining uncomfortable postures, such as stooping and kneeling, for extended periods of time. We present a wearable robot, called MantisBot Alpha, that consists of two expandable robotic arms that brace a worker near the ground and allows them to perform bi-manual tasks. The key component of this new design is a novel linkage mechanism that provides adjustment of both the worker's distance to the ground and their torso tilt. The mechanism link parameters are optimized such that a) its expansion rate is high enough to push off the human body from the ground and fully contract the scissor arm when not used, and b) it allows the worker to reach within a large space while c) it is light enough for wearability. The linkage mechanism also avoids the singularity problem in standard scissor mechanisms. The actuator design provides a fail-safe system. A prototype has been fabricated to demonstrate the feasibility of the system.