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.

Wearable Devices for Ergonomics: A Systematic Literature Review

“…If a smart garment can be put easily and readily on the users, a body-mounted smartphone is only partially ready to wear. The trunk, which is the most frequent segment covered by smart wearables for ergonomic purposes, is the human location on which also a robot [ 53 ] or a vibrotactile feedback interface [ 21 ] can be placed. Other portions on which a wearable technology can be put on are foot in the case of insole pressure systems [ 46 , 47 ], hand for a smartwatch [ 54 ], or head during the smart glasses use [ 45 ].…”

“…In 3 studies [ 45 , 53 , 54 ] the main ergonomic purpose regards the improvement of the analysed risk factor. In particular, Hahm and Asada [ 53 ] propose a robot to support the user in awkward postures, Jin et al [ 54 ] a smartwatch able to estimate and analyse joint angles and muscle activity, and Kunze et al [ 45 ] a couple of smart glasses for providing real-time feedback to improve the risk factors, blurring or flipping the screen content away from the user.…”

Challenging Ergonomics Risks with Smart Wearable Extension Sensors

“…Some [19,21] employ machine learning techniques and cloud architecture in the research. It is evident that the risk level analysis has attracted the attention of many studies [22][23][24], as well as possible answers to them [25][26][27]. The validation of solutions is mainly performed using established ergonomic methods [28,29].…”