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, named MantisBot Alpha, that consists of two expandable robotic arms that brace a worker near the ground. It allows them to perform bi-manual tasks and assists them in standing up and kneeling down. 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 the tilt of their torso. The mechanism link parameters are optimized such that a) its expansion rate is high enough, 1:2.43, 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 larger working space while c) it is light enough for wearability. The linkage mechanism avoids the singularity problem in standard scissor mechanisms. The mechanical design of the system ensures it is fail-safe. A prototype has been fabricated to demonstrate the feasibility of the system. Keywords: Human Augmentation, Supernumerary Robotic Limbs, Exoskeletons, Mechanism Design, Industrial Robotics