The Torsional Vibration Analysis And Control Of Rolling Mill’s Main Drive Nonlinear System

Now the rolling machine developed towards the direction of large-scale, high-speed.With the increase of rolling speed, rolling strength and yield, the torsional vibration ofrolling mill drive system is more outstanding. The occurrence of torsional vibration willinfluence the steel products’quality and yield, even destroy the rolling equipments, so theresearch about the torsional vibration is very significant. The four aspects with modelingof torsional vibration, solution, stability analysis and control in rolling mill main drivesystem are studied based on strip mills. The instability rules of torsional vibration systemare analytically given, and the corresponding control strategies are presented. Thatdeepens the torsional vibration research of rolling mill main drive system.Firstly, considering the influence of time-varying stiffness and nonlinear damping,the torsional vibraton model of rolling mill main drive system with two masses. Thesystem is solved with the aid of method of multiple scales, and the bifurcation phenomenaof system is analysed by the way of Hopf bifurcation theory.Secondly, researching the stability of torsional vibration system in rolling mill maindrive system with strongly nonlinear stiffness, the analytic solutions and frequencyresponse equation are solved by the method of MLP, and the influence of parameters onvibration of system is analysed. The results show that the change of incentive amplitudemight lead the system into instability and chaos motions. The whole change process isdescribed with bifurcation diagram, maximum Lyapunov exponent and Poincare crosssection view, and the chaos phenomenon is controlled by the addition of motivation.Thirdly, the torsional vibration model of rolling mill main drive system is establishedfrom the angle of coupling. The average equation of system is solved with the aid ofmethod of multiple scales, and the necessary and sufficient condition of Hopf bifurcationand periodic motion’s stability are given. In order to avoid harm of bifurcation in torsionalvibration system, the Hopf bifurcation point is moved and the bifurcation behavior iscontrolled through the structure of state feedback controller. Last, the numerical simulation verifies the results.