Design And Simulation Study Of Hydraulic Control System For50T Ceramic Core Injection Machine

Ceramic core injection machine is the key equipment in the production of investmentcasting. The ceramic cores produced by Injection machine will directly affect the qualityof the castings. For the current domestic ceramic core injection machine, the control ofsome technical parameters in the process of injection (such as injection pressure, injectionrate, packing pressure, etc.) is not accurate. Scrap rate of the ceramic core produced bythese Injection machine is very high. Therefore, researching a good performance hydrauliccontrol system of ceramic core injection machine is of great significance.In this paper, taking the50T ceramic core injection machine as an example, thehydraulic control system of injection machine is designed. And the electro-hydraulic servosystem of injection machine’s mathematical model is set up. With application of theMATLAB/Simulink emulated platform, the established position control system for theinjection stage and pressure control system for the holding stage are simulated. And PIDcontrollers are proposed to the two systems. But the actual hydraulic servo system has thecharacter such as time-varying and nonlinear, and the spring stiffness of the load in theinjection system changes caused by injecting time and volume difference of molds.Therefore, in this paper, fuzzy control strategy is used for the uncertainty of the model andchanges in parameters.Aiming at performance requirements at different stages in the control process, theconventional fuzzy controller, the parameter self-tuning fuzzy controller and compositeparameter self-tuning fuzzy controller are designed. The step response curves andperformance indexes are gained through the simulation of injection system adding threekind of control strategies. By comparing simulation results of PID controller，theconclusion composite parameter self-tuning fuzzy controller has the best control effect isdrawn. The influence of the parameters on the system performance，the performance ofswitch system and nonlinear model are discussed when adding the control strategy. Bycomparing with the PID controller, composite parameter self-tuning fuzzy controller hassignificant advantage in such fields as robustness, nonlinear problem and dynamic qualities of control system.