Integrated scheduling for ring layout multi-station multi-robot welding system with dual function robots and jump stations operations

Robotic automated production is the best choice for large-scale manufacturing in the modern automotive industry. Optimizing robotic welding system in an integrated manner is crucial to achieving efficient production. Current research primarily addresses the limited integration of sub-problems for basic production lines. The integrated scheduling of complex coupling challenges in multi-station multi-robot production line is explored in this paper. Tightly coupled sub-problems such as robot allocation, task allocation, dual-function robot scheduling, human–robot cooperative work and welding sequence planning are comprehensively studied and modeled, accounting for numerous constraints in production line composition and parts assembly. Meanwhile, the issue of robot jumping stations operate is also investigated. These complex coupled problems with numerous constraints are incorporated into a unified and novel comprehensive scheduling framework. On this basis, an integrated scheduling model considering robots accessibility, welding accessibility, welding integrity and process feasibility constraints is established, along with an algorithm is proposed to optimize the problems in the model. A five-layer chromosome, featuring two hidden layers, is designed to represent the decision space of the multi-station multi-robot welding system integrated scheduling (MSMRWS-IS) problem. To ensure robot accessibility and welding completeness during evolution, a chromosome correction method is devised. Finally, the proposed STNSGA-DFC is compared with five multi-objective evolutionary algorithms (MOEAs) across four test instance groups. The experimental results demonstrate that STNSGA-DFC outperforms the comparison algorithms in terms of overall performance. The model and optimization method presented in this paper offer significant potential for improving mass production efficiency in industrial environments and hold significant practical value for the complex coupled welding system integrated optimizing.