Research On Electromechanical Vibration Nonlinear Control Of Strip Rolling Mill Main Drive System

Strip rolling is an important production link in the steel industry.In the rolling process,due to the production environment and complex conditions,a variety of disturbance are produced and affect the strip quality.Among them,the rolling mill main drive system nonlinear electromechanical vibration is an urgent problem to be solved.Aiming at the single-mass model of rolling mill with delay nonlinear factors,a dynamic sliding mode controller(DSMC)based on ESO is designed.ESO is used to estimate the system state and state of the disturbance,and the estimated value of the disturbance is directly compensated to the DSMC,avoiding the influence of error when Artificially estimating the disturbance.The characteristics of the second-stage convergence effectively alleviate the chattering problem.The simulation results show that the dynamic sliding mode controller can effectively improve the system response speed to 0.4s and reduce dynamic speed drop to less than 5%,while it has very strong robustness when the parameter is changed.Aiming at frequency harmonics and load harmonics on two-mass model of main drive of rolling mill.In order to eliminate the two kinds of harmonics on the electromechanical vibration at the same time,a multi-frequency filter is constructed by cascading the adaptive notch filter on the control structure.The MATLAB simulation shows that the designed filter can reduce the interference strength of frequency conversion harmonic and load harmonic more than one time,and the amplitude of the system's torsional vibration also decreases from 1.5rad/s to 0.2rad/s.Compared with single frequency notch filter,the filter can effectively filter the influence of harmonics of multiple frequencies.Aiming at the problem that the two-mass model of the main drive contain non-linear clearance and stick-slip friction,a dynamic surface controller(DSC)based on ESO is designed.ESO is used to estimate the state of the system and disturbance,and the observation result of the disturbance is input into the DSC as compensation.The ultimate control law is obtained for each step of the DSC to solve the problem of "complex explosion" with TD differentiator.The simulation results show that the DSC controller can solve the influence of the effective clearance factors of electromechanical vibration,compared with ADRC method,the response time of the system is reduced to about 0.7s at the same time,overshoot is reduced 3.5%,providing a new idea for the torsional vibration system of rolling mill gap suppression.