Digital Twin System for Robotic Multi-layer and Multi-pass Welding of Medium-Thick Plates in Unstructured Environment

In unstructured environment, multi-layer and multi-pass welding system of medium-thick plate is disturbed by external environment. The automated welding system requires higher accuracy and stability. Traditional robotic welding system lacks real-time monitoring of the welding process, and it cannot respond quickly to disturbances in an unstructured environment. Therefore, accuracy and stability cannot be guaranteed. Digital twin technology is a novel approach that enables monitoring and control of the system in real-time. In this paper, a new digital twin system for medium-thick plate welding in unstructured environment is presented, and a method of welding state evaluation and monitoring is proposed. Firstly, a welding robot digital twin model is built using three-dimensional modeling software and a real-time 3D engine. Secondly, a stability evaluation model for the multi-layer and multi-pass welding process is established according to the welding process parameters. Based on the evaluation model, the welding process can be monitored and the welding formation quality can be predicted. Experimental results demonstrate that the proposed digital twin system can evolve the welding process of medium-thick plate in unstructured environment. Welding quality can be predicted according to the digital twin system. The digital twin system effectively suppresses the interference of unstructured environment on multi-layer and multi-pass welding of medium-thick plates.