Research On Iterative Learning Control Of Injection Molding Machine Switching Process

With the rapid development of society,the demand for plastic products is growing,and at the same time,the production and quality of plastic put forward higher requirements,and the injection molding machine as the main equipment of plastic processing,its control parameters,plastic material and injection process are closely related.In the era of rapid development of artificial intelligence,it is particularly important to study the control method of injection molding process.The injection molding process has the characteristics of batch,time varying,nonlinear and repeatability.Injection process mainly includes injection,pressure preservation,cooling and other processes,among which injection and pressure preservation are the most critical stages for the whole injection process.According to the characteristics of injection process,this paper adopts iterative learning control method to simulate injection process and pressure retaining process respectively.At the same time,aiming at the problems of control signal hopping and high frequency interference in the process of injection molding machine switching,a filtered iterative learning control method based on the process of injection molding machine switching is designed.The random disturbance function is added to the switching point,and the simulation results show that the filtered iterative learning control can effectively filter the random interference,and the system does not diverge,so that the signals can be tracked accurately.In the simulation of injection pressure preserving switching process,the filtered iterative learning control has a strong inhibition effect on random disturbance,but there is a large overshoot near the switching point,leading to unsatisfactory simulation results.Therefore,this thesis studies the position-pressure control switching process of injection molding machine control system,and proposes a feedforward tracking compensation strategy for the problems such as control signal hopping and high-frequency interference,which ensures accurate tracking of control signals and makes the position control switching to pressure control more stable and smooth.Injection molding machine is an industrial equipment running along a straight line,and the motor is the core power device of injection molding machine,so this paper chooses permanent magnet linear synchronous motor(PMLSM)for research.By building the PMLSM semi-physical platform,the filter-based iterative learning control is established on the basis of vector control.Meanwhile,the filter-based iterative learning control and Pd-based iterative learning control respectively control the linear motor thrust when random disturbance is added.The experimental results show that the filter-based iterative learning control can effectively filter the linear motor thrust unless repeated disturbance is added.Improve the control precision,improve the control effect.