鉛直加速度を考慮した取鍋搬送の固有周波数推定と時変ノッチフィルタによる液面制振

抄録

  In modern casting processes, the automation of ladle and pouring device transfer is essential for smart factories. A major challenge is to suppress liquid surface vibration (sloshing) while maintaining high transport speed, since sloshing can cause overflow, oxidation, and safety risks. Although sloshing suppression has been studied extensively for horizontal transport, few research works address three-dimensional transfer paths where vertical acceleration inevitably arises. Prior studies on vertical sloshing mainly concern seismic excitation or aerospace propellant tanks, leaving production-line applications largely unexplored.

  In this study, we propose a suppression method that incorporates vertical acceleration into the estimation of the sloshing natural frequency. The classical formula for a cylindrical container was extended by introducing apparent gravity, and its validity was verified through Computational Fluid Dynamics (CFD) simulations. The simulations confirmed that the extended formulation accurately predicts frequency shifts under varying vertical accelerations and liquid levels, including nonlinear shallow-water conditions. A notch filter was then designed based on the estimated frequency. By updating filter parameters online, the method adapts to both vertical acceleration and liquid-level variation. Experiments using a robot arm transporting a cylindrical container along three-dimensional paths demonstrated effective suppression of residual oscillations while preserving transport efficiency.

  Overall, by integrating theoretical modeling, CFD validation, and robot-arm experiments, the proposed framework provides a reproducible basis for sloshing suppression in safe and efficient three-dimensional ladle transfer for casting operations.