Yuan Li, Haibo Xu, Pengjie Wei, Kailin Wang, Yanbing Hu, Kang Zhu, Jun Zhou, Yang Zhang
Zhejiang Geely Run Automobile Co., Ltd. Ningbo Hangzhou Bay Branch, Hangzhou, China
Abstract: To address the persistent positional mismatches between simulated welding point coordinates and the actual locations of robotic equipment encountered in automotive body shop production lines, this paper introduces a novel reverse calibration methodology for welding spot trajectories. The approach is implemented within the established Process Designer/Process Simulate (PD/PS) simulation environment. Conventional methods in robot program reverse export result in significant deviations, making them inadequate to meet engineering precision requirements. This study aims to bridge this technical gap. Our solution involves the development of a dedicated RobotTool plugin. Leveraging this empirical data, a sophisticated spatial geometric transformation model is constructed. Through this model, the key transformation matrix describing the relationship between the theoretical simulation coordinate system and the actual physical coordinate system is solved. To improve calibration accuracy and enhance robustness against measurement noise, the least squares optimization algorithm is introduced in conjunction with a specifically designed error optimization function. This mechanism effectively filters high-precision inlier data points, thereby establishing a robust deviation compensation model. Comprehensive experimental validation conducted on representative production setups demonstrates the efficacy of the proposed method. It successfully achieves reverse correction of both welding points and their interconnecting trajectories, consistently controlling positional errors within a stringent tolerance of ±10mm. Crucially, for retrofit and production line upgrade projects, this method allows legacy vehicle welding programs to be directly output as production-ready, zero-debugging industrial robot code following the calibration process. This capability drastically reduces the traditionally intensive on-site commissioning workload by over 80%, thereby significantly enhancing operational efficiency and accelerating the deployment cycles for flexible manufacturing systems handling multiple vehicle models.
Keywords: Welding spot Trajectories; PD/PS Platform; Least Squares Optimization; Automotive Body Shop; Industrial Robot
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