Research On Robust Control For Torsional Oscillation Of Strip Rolling Mill’s Mechanical And Electrical Drive System

The torsional vibration of strip rolling mill’s mechanical and electrical drive systemcould affect the quality of the product, and even causes the damage of steel rollingequipment. With the improvement of rolling speed and rolling strength, the torsionalvibration problem increasingly stands out, so the study of torsional vibration on the mill’smechanical and electrical drive system is great significant. In this paper, the strip rollingmill is used as the research object, and the torsional vibration model of strip rolling mill’smechanical and electrical drive system is established. Based on H∞theory, the torsionalvibration robust control problem of the strip rolling mill’s mechanical and electrical drivesystem is studied.Firstly, based on the kirchhoff’s law, the law of electromagnetic induction, Newton’ssecond law, the torsional vibration model which considers the nonlinear of armaturereaction is established; Based on the generalized dissipation Lagrange theory, the torsionalvibration model which considers the nonlinear of quasi-periodic stiffness is established.Secondly, in allusion to torsional vibration model of strip rolling mill’s mechanicaland electrical drive system which considers the nonlinear of armature reaction, and basedon H∞theory, the LMI method and the related lemmas, the sufficient condition for theexistence of state feedback controller is obtained, and the concept for the approximatematrix of the system steady state matrix is put forward, Three state feedback controllersare obtained by solving combined with the given sufficient condition. And they aredisposed for the control inputs of the system with the feed-forward compensator. Theinstance simulation shows that under the effect of three control inputs, the motor speedcan get good control effect all.Thirdly, for the electrical drive system torsional vibration model of strip rolling millcontaining friction damping, the vulnerability of the controller is Considered. Based on H∞theory, Lyapunov stability theory and LMI method, robust non-fragile controller isdesigned. The sufficient conditions for the existence of state feedback controller is givenwithout considering vulnerability. Two groups state feedback controller are acquired by the sufficient conditions Take the average of two groups state feedback controllerparameters is regarded as robust non fragile controller. The correctness and effectivenessof two kinds of designing robust non-fragile are verified by the results of instancesimulation.Finally, for the electrical drive system torsional vibration model of strip rolling millcontaining shock stiffness nonlinear. Based on H∞theory and Lyapunov stability theory,The robust state feedback controller is designed which satisfies the system robust stabilityand robust performance. A feed-forward compensator is designed at the same time. Thesteady-state error is eliminated. The instance simulation shows that motor speed trackingand the connecting shaft torque control of the strip rolling mill electromechanicaltransmission system can be realized effectively by the controller and compensatorimplements.