[Objective] This study addresses the unique technical challenges of large-span overhead cranes operating on concentric dual circular tracks within synchrotron radiation light source storage rings.
[Methods] Drawing on the engineering practice of three major projects—Shanghai Synchrotron Radiation Facility (SSRF), High Energy Photon Source (HEPS), and Hefei Advanced Light Facility (HALF)—three core technologies are systematically investigated: PLC closed-loop control, curvature-coupled three-layer precision control, and differential-speed synchronous driving. A three-layer precision coupling model and a gap–closed-loop coupling theory with a horizontal wheel gap calculation formula are established. [Results] On-site commissioning of the HALF project demonstrates that an adequate horizontal wheel gap is a necessary prerequisite for effective closed-loop control. The synthesized three-layer precision reaches ±0.62 mm, satisfying the ±1 mm design specification with a 38% safety margin.
[Limitations] The curvature coupling model is based on small-deformation assumptions and linear creep theory; nonlinear effects under large curvature radius ratios or extreme temperature gradients have not been considered; the gap theory has been verified only with a single operating condition.
[Conclusions] This work fills the domestic technology gap in concentric dual circular track large-span overhead cranes and provides a theoretical basis and engineering reference for the design and manufacture of similar large-scale precision lifting equipment.
