Research On Liquid Pressure System Of Low Pressure Cantilever Casting Machine

The liquid pressure system of the low pressure cantilever casting machine is a kind of liquid lifting system for the low pressure cantilever casting machine.The working process of the liquid surface pressurization system is to step and pressurize the insulation furnace by pneumatic system,so as to change the pressure acting on the surface of the metal solution in the furnace and make the metal solution overcome gravity and other factors,and use the riser to enter the mold to complete the whole casting process.However,in actual working conditions,due to the structure of pneumatic components and the change of temperature in the holding furnace,the pressure of filling system is not accurate,which is difficult to describe with complicated mathematical models.Therefore,in order to improve the lag phenomenon of pressure and avoid the derivation of complex mathematical models,we need to add a LADRC to the pneumatic system to improve its performance.This project first calculated the low pressure casting process parameters of the selected concrete castings.However,due to the specificity of the production of the castings,the numerical value of the theoretical calculation does not guarantee the quality of the castings produced to meet the standard.Therefore,based on the ProCAST casting simulation software,many groups of simulation experiments are carried out on the concrete castings,and the quality of the castings is judged by the post-processing results.Based on the results of several simulation experiments,more accurate process parameters are determined to determine the pressure curve at the same time.Secondly,according to the determination of the pressure curve and the understanding of the process of low pressure casting,the overall design scheme of the pneumatic pressure system is determined.The pneumatic pressure system is further designed,and the parameters of each component are calculated and selected.Meanwhile,the designed pneumatic system is modeled in the AMEsim simulation software,and the logic control signal is added.The parameters of the process and the specific parameters of each component are input,and the pneumatic system is simulated.By comparing the established process curves and simulation results,it is found that there is a certain lag phenomenon in the pressure output of the pneumatic system.Finally,in order to improve the phenomenon of pressure lag in the pneumatic system and ensure that the liquid level pressurization system can meet the technologicalrequirements,LADRC is added to improve its rapidity and stability.By deducing the transfer function of the components needed for the closed-loop system and studying the LADRC,we have determined the overall structure of the liquid level pressurization system using the LADRC.In the Matlab/Simulink software to carry on the modeling and Simulation of the tuning parameters,through the time domain analysis results were observed and compared with control effect,control effect with the PID controller,verify the rapidity and applicability of linear auto disturbance rejection control strategy system of pressurized liquid.Furthermore,disturbance is added to the pressurized system with PID controller and LADRC.The simulation results show that the stability of the LADRC is better than that of the PID controller.