Statistical Dynamics of the Rolling Mills

Uncertainty of technology and equipment parameters is particular for the rolling mills dynamics. Contact friction produces a wide band stochastic impacts which cause chatter vibration in the middle and higher natural frequencies range (100-1000 Hz) of the mill. Strip elasto-plastic deformation as a nonlinear spring in the stand depends on random technology parameters (rolls bending, strip tensions, mill speed). The transfer functions were used for principal mode distribution and chatter vibrations control in the cold rolling mills. The second cause of uncertainty is wear (backlashes) which makes drive train an essentially nonlinear system. The backlashes gaps and rolling loads are always uncertain at the beginning of transient process in the hot rolling mills causing dynamic torques scattering in the multibody drive trains. The low frequency (10-20 Hz) torsional vibrations are investigated. The output dynamic load distribution parameters were obtained. Statistical aspects of the mill control and diagnostics are discussed.