Assessment of vibrations induced in factories by automated guided vehicles

Abstract

This study proposes a simplified sub-structural model to explore the floor micro-vibration induced by automated guided vehicles in thin-film transistor liquid crystal display factories. Time history analyses of a sequence of automated guided vehicles moving loads considering various car spacings on an equivalent three-span continuous beam model of a thin-film transitor liquid crystal display factory were simulated. The effectiveness of vibration control using viscoelastic dampers was also examined. Numerical simulations demonstrate that the simplified method can predict the measured floor vibration spectra with satisfactory accuracy and that the automated guided vehicles induced floor vibrations without control exceed the acceptable VC-B level required for the installation of specific precision process tools. The application of energy dissipation devices has shown to be effective in vibration mitigations as they enhance the damping characteristics of a multi-span floor system. The maximum response of the whole continuous beam induced by a group of automated guided vehicles can be effectively suppressed to a desired VC-B level if multiple viscoelastic dampers are implemented along the automated guided vehicles moving bay and the spacing between each automated guided vehicle is properly adjusted. The simplified analytical method can help engineers quickly assess the level of automated guided vehicles-induced floor vibration and assist in the design of low-vibration floor systems in high-technology factories.