The Stability Analysis And Control Of Rolling Mill's Main Drive Torsional System

With the development of the speed and the intensity, it has become common that the phenomenon of unusual vibration unstability of roller system in rolling mills. The nonlinear model and coupled nonlinear systems of the rolling mill's main drive system are studied from four aspects with models, responses, stability and control based on strip mills. The rule of unstable vibration and control method are analytically given, and the theory of rolling mill's vibration in engineering is improved.The rule of drive vibration of rolling mill's is studied. The dynamics models of main drive system with nonlinear damping and nonlinear stiffness are established. Based on the models, the theory of rolling mill's vibration and control method can be analyzed further.On the basis of torsional vibration of rolling mill dynamic model, the system response of the torsional vibration dynamic models under periodic excitation is studied by the method of nonlinear vibration theory. The approximately solution of the system is obtained when the primary resonance occurs. The character of vibration and rule of response are obtained by the analytic method when rolling mill destabilization.The stability problem of torsional vibration of rolling mill's with time varying stiffness and nonlinear damping is studied by the singularity theory, and the transfer concourse and topological structure of bifurcation function are obtained. The necessary and sufficient condition of the stability of torsional vibration system of rolling mill's is deduced by using the Routh-Hurwitz criterion. The stability of strongly nonlinear system of rolling mill's which contains clearence is studied and its process of unstability is revealed.The stability control of main drive torsional vibration system of rolling mill's is studied so as to avoid the harm of unstability. The stability control of main drive system is achieved by designing the time-delay feedback controller and this can supply a theory for the stable work of rolling mill. The analytical results are in good agreement with numerical simulations.