Study On Temperature Control Of Heating Furnace Based On Predictive Control In Magnesium Alloy Furnace Rolling Process

Due to the narrow temperature range of the magnesium alloy,the edge cracking during the rolling process is widespread,and it is impossible to obtain high quality magnesium alloy strips by the traditional rolling method.The coil rolling mill can effectively reduce the temperature drop of the strip during the rolling process,it can effectively reduce the production of edge cracks in the magnesium alloy rolling process and improve the yield rate of the magnesium alloy strip.In order to reduce the exposure time of magnesium alloy strips in the air,temperature compensation is performed on the magnesium alloy strip to achieve precise control of the temperature of the magnesium alloy rolling process.With the characteristics of good heating quality,continuous work,and easy realization of automation,etc,the roller tunnel furnace was designed to combine the equipment form of the furnace coil rolling mill with the reheat furnace before rolling,and the rolling process technology and temperature model were developed to improve magnesium alloy strip quality,reduce the magnesium alloy edge cracking.The temperature compensation section has an important influence on the process of the magnesium alloy strip rolling.The accuracy of temperature compensation directly affects the product quality of the final magnesium alloy strip.Therefore,the study of the control of the temperature-recovering furnace after the rolling of the magnesium alloy has an important value for the production of the magnesium alloy strip.Based on the design project of magnesium alloy coil rolling production line of a company,this paper focuses on the design and analysis of the temperature control system of the magnesium alloy temperature heating furnace.The research content is mainly divided into the following three aspects.Firstly,based on the analysis of the heat transfer mechanism in the furnace,a heat transfer model for the plate,a heat transfer model for the furnace wall,and a heat transfer model for the radiant tube were established.Combined with the energy balance equation in the furnace,the furnace temperature is solvedusing the Newton method to solve the ternary model.The function relationship between the furnace temperature and the strip temperature was established,and then the heating furnace temperature model was established.The first-order inertial furnace temperature model is obtained by fitting the data sample obtained by the model and the fitting accuracy is verified,so that the furnace temperature model can be combined with the generalized predictive control algorithm.Secondly,the generalized predictive control algorithm is used instead of the traditional control method to control the furnace temperature,and simulation experiments are performed.The simulation results show that compared with the traditional PID control strategy,the warming trend of the furnace temperature control process based on the generalized predictive control algorithm is more stable,the overshoot is smaller,and the maximum overshoot does not exceed 5°C.For the problems that the multi-variable and multi-constraints of the heating furnace lead to the large amount of calculation of the generalized predictive control rolling optimization and the lack of accuracy of the solution,the constraint conditions were improved to solve the problem of high-dimensional matrix computation in multivariable generalized predictive control.The improved particle swarm optimization algorithm was used to solve the problem of complex constrained space,so as to improve the accuracy of the optimal control quantity in the generalized predictive control and ensure the accuracy of the furnace temperature control.Simulation results show that the improved particle swarm optimization algorithm has better accuracy for solving the problem of complex constraints.Finally,the furnace heat transfer calculation model and the furnace temperature prediction control algorithm were developed and the simulation system of the magnesium alloy heating furnace was established.For the different specifications of magnesium alloy strips for visual simulation research,and then adjust the parameters of the design model optimization,lay the foundation for the industrial application of the temperature control system of the magnesium alloy rolling process.