A VR-based approach in conducting MTM for manual workplaces

Valentina Gorobets,Christian Hirt,Valentin Holzwarth,Andreas Kunz,Noëlle Jufer

doi:10.1007/s00170-021-07260-7

Abstract

Due to current trends in the manufacturing industry, such as mass customization, manual operations contribute drastically to the overall costs of a product. Methods-Time-Measurement (MTM) identifies the optimization potential of manual workplaces, which significantly influences a worker’s productivity. However, traditional MTM requires great efforts to observe and transcribe manual assembly processes. Yet, various digital approaches exist that facilitate MTM analyses. While most of these approaches require the existence of real workplaces or cardboard mock-ups, it would be beneficial to conduct a virtual MTM in earlier phases of production planning. However, the quality of virtual MTM analyses compared to traditional MTM conducted in reality has not been assessed yet. This paper is addressing it by conducting a comparative user study with 21 participants completing the same task both at a real and virtual workplace, which they access via virtual reality technology. Our results show that participants’ MTM-2 values achieved at the VR workplace are comparable to those at the real workplace. However, time study data reveals that participants moved considerably slower in VR and thus needed more time to accomplish the task. Consequently, for the measurement of manual work in VR, it is even necessary to utilize predetermined times, such as MTM-2 since time study data is insufficient. This paper also serves as a proof of concept for future studies, investigating automated transcription systems that would further decrease the efforts conducting MTM analyses.

Highlights

Manual operations in a production substantially contribute to the overall costs of a product and should be Figure 1 shows a typical structure of a manufacturing company
This section describes the findings of our comparative user study, including MTM-2 analysis and time study for the task conducted in reality and virtual reality (VR)
While there is already a good correlation between the MTM-2 analysis in reality and VR, we made some observations during the course of the study, which could be an explanation for the typically longer task completion time when being exposed to the virtual environment (VE)

Summary

Introduction

Manual operations in a production substantially contribute to the overall costs of a product and should be Figure 1 shows a typical structure of a manufacturing company. The level of detail increases regarding manual work that can be analyzed. The details in the description of manual work on the enterprise and factory level are not sufficient, which makes it difficult to conduct an optimization. Manual worker operations are mainly evaluated on machine level, at fixed workplaces, by applying so-called MTM (Methods-Time Measurement). MTM is one of the most widely used predetermined time measurement systems, which defines a particular time measured in so-called Time Measurement Units (TMUs) for each basic operation described in it [6].

Objectives

Results

Discussion

Conclusion