Analysis of controllability and observability of multistand pipe mill rolling

摘要

The purpose of article is to report an approach to application of linearized mathematical models of floating mandrel multistand pipe mills. Mathematical model is supposed to be set of linear equations for single stand, assembled to whole mill model by taking in account interstand connection by velocities and tensions. Such a model can be converted to the set of ordinary differential equations when momentum equation of mandrel is taken in account. Twostand fragment is considered. Coefficients of mathematical model are calculated by finite-element modeling with commercial FEM code DEFORM-3D. It is shown, that at least in the near-zero interstand tension case the floating mandrel velocity can be unobservable, i.e., unable to be calculated from measurements of interstand tension.