Electromechanical Coupling Dynamics And Control Of Dual-source Composite Oscillation System Of Continuous Casting Mold

The mold is the core reactor in which high temperature liquid steel is quenchedcooled and solidified into billet in continuous casting production.In order to ensure the continuity of continuous casting production,the mold must vibrate according to specific rules under the drive of oscillation system.The new dual-source composite oscillation system has good impact resistance,intelligent control of amplitude,frequency and waveform deviation rate,and has broad application prospects.Aiming at the complex working conditions of continuous casting production,it is of great significance to study the electromechanical coupling dynamics of the oscillation system and build a highprecision control method,which is of great significance to promote the application of the oscillation system.A kinematic model was established for the configuration of the seven-rods linkage in the dual-source composite oscillation system,and the mapping relationship between the angular velocity,phase difference,waveform deviation rate of the oscillation system and the frequency,amplitude and waveform deviation rate of the mold was deduced.A new synchronous control model was presented to adapt to the change of casting billet pulling speed.The Lagrange method was used to construct the dynamic model of the dual-source composite oscillation system,and the variation law of the load torque of the motors were analyzed.The results showed that the load torque of the motor has time-varying characteristics and is positively correlated with the angular velocity and the deviation rate of the waveform.The load torque of the motor first increases and then decreases with the increase of the phase difference,and a big sudden change occurs when the direction of the mold relative to the billet changes.The dynamic model of the dual-source composite oscillation system and the mathematical model of the permanent magnet synchronous motor were synthesized into the electromechanical coupling dynamic model of the system.Based on the model,the sliding mode and cross-coupling composite control method was proposed.The simulation analysis showed that the sliding mode controller could achieve rapid convergence under different working conditions and had good robustness.The cross-coupling controller keeps the phase difference stable and the synchronization control precision is good.In the process of parameter adjustment,the tracking curves of mold displacement and velocity basically coincides with the theoretical curves,which indicates that the control method can realize the online accurate control of all oscillation parameters of mold.A prototype of the oscillation system was designed and processed,and the mold oscillation data under different operating parameters were tested.The experimental speed tracking curves were basically consistent with the theoretical curves,and the relative errors between the experimental speed and the theoretical speed were less than 5%.It is proved that the sliding mode-cross coupling composite control method can ensure the system has good accuracy and stability under time-varying load conditions.