Modelling a flexible mast of an industrial truck as a distributed parameter system for industrial applications

Industrial trucks with extendable masts are essential for goods handling and storage. However, mast flexibility can cause vibrations, increase handling times, and damage the structure, motivating model-based control. Existing industrial models often require extensive measurements and parameter fitting. This study presents a distributed-parameter model of a flexible industrial truck mast in the push, lateral, and torsional directions. The equations of motion are derived using early lumping and the Lagrangian formalism. Modal order reduction decreases the number of degrees of freedom, while numerical sensitivity analysis identifies the most relevant physical parameters. For online implementation on industrial control units, the parameter-varying system matrices are approximated by monomials. Frequency-domain experiments on various mast configurations show strong agreement between the reduced model and measurements. Time-domain validation, conducted for the push direction, additionally demonstrates accurate dynamic behaviour for this mode.