Ergonomics, digital twins and time measurements for optimal workplace design
Authors: Vujica-Herzog Natasa , Buchmeister Borut , Breznik Matic 
Published: June 2022

Ergonomics and Human Factors are both defined as a scientific discipline concerned with understanding the interactions between workers and other elements of a system. The implementation of ergonomics in industrial engineering, where workers are an integral part of the system, is very important in the development phase of the product/production and also in the planning of production technologies. The interaction between man and machine can be very intense in mass production, especially in assembly lines, and is therefore the focus of process optimization. In addition, appropriate workplace design has long-term effects on the worker. It is well known that it can prevent musculoskeletal complaints, increase productivity and reduce production costs.As part of the current trend of Industry 4.0 (I4.0), the traditional approach to workplace design is becoming intertwined with "smart" paradigms such as sensors, computing platforms, communication technology, control, simulation, data-intensive modelling, and predictive engineering. It is therefore important for companies to understand the great potential of the I4.0 concept and leverage its benefits in terms of moving from machine-dominated manufacturing to digital manufacturing.These technologies offer us the possibility to reproduce the work environment in a virtual scenario where it is possible to simulate manual tasks, evaluate ergonomic indices and perform time analysis at the same time. The idea of using ergonomic simulation software is not new. Several attempts have been made in Europe in the past. Starting with DELTA's ERGOMAS, ERGOMan systems, Siemens Jack and more recently Process simulate, both possibly supported by Xsens suit. With the I4.0 paradigm in mind, we examined the featured computing platforms developed from 1994 to the present to track the progress and changes made. For simulations, the most progress was made with the development of the Task Simulation Builder interface and later an important step was made with the development of sensor technology for motion capture. For example, for assembly lines, an integrated approach for setting working times was developed using the classical MTM approach and EAWS methods. With these technologies and accumulated knowledge, the design process changed rapidly and several published papers show the benefits of computer-aided approaches also for timing analysis. Based on the presented facts, the question arose: can computer-aided approaches integrated with ergonomics replace the existing standardised approaches for time determination? In our research, a case study of workplace design was conducted using two of the latest platforms, Siemens Jack and Process Simulate in conjunction with Xsens suit. A collaborative human-robot workplace was designed as a digital twin and tested in our lab with 6 subjects considering their anthropometric measurements. The human movements were converted into computer software and evaluated using OWAS analysis for ergonomics and MTM method for timing. The results of the research carried out will help us to evaluate a similar approach carried out with two different computer platforms and to answer the question of the usefulness and reliability of the presented platforms also for time analysis.