Study On Stability And Control Of Strip Rolling Mill's Main Drive Torsional System Under Parametric Excitation

Strip rolling mill is the key and core equipment in iron and steel industry, as thecontinuous increasing of the rolling speed and strength, the torsional abnormal instabilityphenomenon of the rolling mill's drive system occur frequently, this phenomenon severelyaffect the production and constrained the rolling efficiency and the advancement of theproduct quality. In this article, the parametric torsional dynamic models were establishedby considering the nonlinear factors, for example: parametric excitation, based on thedrive system of strip rolling mill, then the torsional instability mechanics of the drivesystem under the effect of the parametric excitation were studied in the way of qualitativeand quantitative, and the rule of the structural parameter and the rolling parameter to thestability of the drive system. On this basis, the control of the instability was researched,which supply the theoretical basis for the optimum design of the structure, kinetic controland the fault precaution and processing.Firstly, considering the nonlinear parametric rigidity, nonlinear damping of load, thenonlinear parametric excitation torsional vibration dynamic models of strip rolling millwere established, which enriched the theoretical models of the study of torsionalinstability.Secondly, on the basis of nonlinear parametric torsional dynamic models, thefrequency-amplitude equation and the bifurcation response equation were obtained bysolving the nonlinear model under different working condition with the method ofmultiple scale of the nonlinear vibration theory.Thirdly, based on the bifurcation response equations, the stability of the models wasanalyzed. The stability of the system solution of the quasi-periodic parametric torsionalsystem by using the method of Jacobi matrix; and the stability of the jointed shaftparametric excitation nonlinear torsional dynamic model was studied by using the methodof singularity. The topology structure of bifurcation curve of the transition set and thetorsional characteristic and the discipline of the drive system were given.Finally, the instability influence of the main drive system potentially caused by the parametric excitation was studied based on the theoretical analysis upward. Thebifurcation control and time-delay feedback control were used to control the stability ofthe main drive system of the strip rolling mill. It can supply theoretical instruct to inhibitor avoid the instability phenomena of the drive system, and then the numerical simulationwere finished for certificating the feasibility and the effectivity of the control method.