*Article* **CNN Training Using 3D Virtual Models for Assisted Assembly with Mixed Reality and Collaborative Robots**

**Kamil Židek, Ján Pitel' \*, Michal Balog, Alexander Hošovský, Vratislav Hladký, Peter Lazorík, Angelina Iakovets and Jakub Demˇcák**

> Department of Industrial Engineering and Informatics, Faculty of Manufacturing Technologies with a Seat in Presov, Technical University of Kosice, Bayerova 1, 08001 Presov, Slovakia; kamil.zidek@tuke.sk (K.Ž.); michal.balog@tuke.sk (M.B.); alexander.hosovsky@tuke.sk (A.H.); vratislav.hladky@tuke.sk (V.H.); peter.lazorik@tuke.sk (P.L.); angelina.iakovets@tuke.sk (A.I.); jakub.demcak@tuke.sk (J.D.) **\*** Correspondence: jan.pitel@tuke.sk; Tel.: +421-90-524-1605 or +421-55-602-6455

**Abstract:** The assisted assembly of customized products supported by collaborative robots combined with mixed reality devices is the current trend in the Industry 4.0 concept. This article introduces an experimental work cell with the implementation of the assisted assembly process for customized cam switches as a case study. The research is aimed to design a methodology for this complex task with full digitalization and transformation data to digital twin models from all vision systems. Recognition of position and orientation of assembled parts during manual assembly are marked and checked by convolutional neural network (CNN) model. Training of CNN was based on a new approach using virtual training samples with single shot detection and instance segmentation. The trained CNN model was transferred to an embedded artificial processing unit with a high-resolution camera sensor. The embedded device redistributes data with parts detected position and orientation into mixed reality devices and collaborative robot. This approach to assisted assembly using mixed reality, collaborative robot, vision systems, and CNN models can significantly decrease assembly and training time in real production.

**Keywords:** assisted assembly; mixed reality; collaborative robot; digital twin; convolutional neural networks
