Research Of Mold Level Predicting Control System In Continuous Casting

Mold level control is an important link in production process on steel continuous casting.The stable mold level can promote the production of continuous casting,improve the surface quality of billet and reduce the occurrence of accidents.Therefore,the stable mold level control research has became an important part of the production control on continuous casting.Aiming at the phenomenon of compensation lag in PID control and other intelligent control,this paper proposed a kind of novel level pre-control system.Its working mechanism is as follows: In the forecast cycle,the detect device calculates the height of level and forecasts the velocity of change.Then the total level changes in the whole control cycle has been calculated,and full compensation in the subsequent compensation cycle has been made.This predictive control runs through the whole production process of continuous casting.When the level interference has not yet been fully formed,the compensation device has started to execute the compensation action.From the mechanism,this semi-active control method could achieved level robust control.The main contents are as follows:(1)This paper proposed a semi active predictive control method.Before the interference has not yet been fully formed,it can be used to predict the level of compensation,which solved the problem of compensation lag in the general control method.(2)According to ray detection theory and predictive control method,the mathematical expressions of compensation cycle and compensation speed has been derived.Simultaneously the hydraulic control system has been designed.(3)Full opening and closing mode is used to analyze pre-control compensation method.It has discussed working mechanism and taken sinusoidal interference as an example.The pre-control compensation level has been calculated.Compared with sinusoidal interference curve,results showed that the fluctuation intensity of liquid level has been reduced by 80.8%.(4)To further consider the response speed of hydraulic system has beenanalyzed.Firstly,the dynamic simulation of the hydraulic control system is carried out.What's more,the steady speed and control cycle of the piston rod are obtained.Secondly,according to prediction control method to calculate the level curve after compensation,this paper has subdivided compensation position and established the corresponding level change table.Then,comparing with interference curve and compensation curve,it has verified that predictive control method has good compensation performance,and the fluctuation strength about level has been decreased by 35%.Finally,this paper not only has analyzed the reason why the compensation curve fluctuates,but also put forward the way to reduce the error compensation on level.