Citation: Asad, U.; Rasheed, S.;
Lughmani, W.A.; Kazim, T.; Khalid,
A.; Pannek, J. Biomechanical
Modeling of Human–Robot Accident
Scenarios: A Computational
Assessment for Heavy-Payload-
Capacity Robots. Appl. Sci. 2023, 13,
1957. https://doi.org/10.3390/
app13031957
Academic Editors: Enrico Vezzetti,
Andrea Luigi Guerra, Gabriele
Baronio, Domenico Speranza and
Luca Ulrich
Received: 15 November 2022
Revised: 14 December 2022
Accepted: 27 January 2023
Published: 2 February 2023
Copyright: © 2023 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
Article
Biomechanical Modeling of Human–Robot Accident Scenarios:
A Computational Assessment for Heavy-Payload-Capacity Robots
Usman Asad
1
, Shummaila Rasheed
1
, Waqas Akbar Lughmani
1
, Tayyaba Kazim
2
, Azfar Khalid
3,
*
and Jürgen Pannek
4
1
Department of Mechanical Engineering, Capital University of Science and Technology,
Islamabad 45750, Pakistan
2
Department of Biosciences, School of Science & Technology, Nottingham Trent University,
Nottingham NG11 8NS, UK
3
Digital Innovation Research Group, Department of Engineering, School of Science & Technology,
Nottingham Trent University, Nottingham NG11 8NS, UK
4
Institute for Intermodal Transport and Logistic Systems, TU Braunschweig, Hermann-Blenk-Straße 42,
38108 Braunschweig, Germany
* Correspondence: azfar.khalid@ntu.ac.uk
Abstract:
Exponentially growing technologies such as intelligent robots in the context of Industry
4.0 are radically changing traditional manufacturing to intelligent manufacturing with increased
productivity and flexibility. Workspaces are being transformed into fully shared spaces for performing
tasks during human–robot collaboration (HRC), increasing the possibility of accidents as compared
to the fully restricted and partially shared workspaces. The next technological epoch of Industry 5.0
has a heavy focus on human well-being, with humans and robots operating in synergy. However, the
reluctance to adopt heavy-payload-capacity robots due to safety concerns is a major hurdle. Therefore,
the importance of analyzing the level of injury after impact can never be neglected for the safety
of workers and for designing a collaborative environment. In this study, quasi-static and dynamic
analyses of accidental scenarios during HRC are performed for medium- and low-payload-capacity
robots according to the conditions given in ISO TS 15066 to assess the threshold level of injury and
pain, and is subsequently extended for high speeds and heavy payloads for collaborative robots. For
this purpose, accidental scenarios are simulated in ANSYS using a 3D finite element model of an adult
human index finger and hand, composed of cortical bone and soft tissue. Stresses and strains in the
bone and tissue, and contact forces and energy transfer during impact are studied, and contact speed
limit values are estimated. It is observed that heavy-payload-capacity robots must be restricted to
80% of the speed limit of low-payload-capacity robots. Biomechanical modeling of accident scenarios
offers insights and, therefore, gives confidence in the adoption of heavy-payload robots in factories of
the future. The analysis allows for prediction and assessment of different hypothetical accidental
scenarios in HRC involving high speeds and heavy-payload-capacity robots.
Keywords:
Industry 4.0; human–robot collaboration; occupational safety; static and dynamic analysis
1. Introduction
Industrial robots, from the last fifty years, have been widely used in industrial manu-
facturing, to the effect of complementing the proficiencies of human workers and relieving
them from non-ergonomic, repetitive, uncomfortable, and dangerous tasks. Robot utiliza-
tion is continuously increasing in industrial environments with a growth rate of about
fourteen percent, yearly [
1
]. Moreover, it is estimated that nearly 2.1 million industrial
robots will be deployed around the world in the near future [
2
]. Conventional industrial
robots work with human workers either in a completely separated or in partially shared
workspaces. The current exposure of humans with industrial robots is up to a limited
extent in the workspace, where the robot is equipped with appropriate safety controls
Appl. Sci. 2023, 13, 1957. https://doi.org/10.3390/app13031957 https://www.mdpi.com/journal/applsci
