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针对目前低压铸造设备液面压力控制问题,实际输出压力值与理论输入压力值存在误差较大,不能很好满足低压铸造设备的需求。对此,提出了基于模糊PID控制的低压铸造设备液面压力控制系统。首先,介绍了低压铸造设备示意图,分析了低压铸造设备液面压力控制的工艺流程。其次,设计了液面压力控制方案,采用了模糊PID控制,计算压力控制变化过程中的气体流量。最后,对模糊PID控制压力追踪误差进行仿真,并且与PID控制方法进行对比。仿真曲线结果表明,模糊PID控制低压铸造液面压力追踪的适应时间为2.0 s,产生最大误差大约为12 Pa,PID控制低压铸造液面压力追踪的适应时间为2.2 s,产生最大误差大约为15 Pa。采用模糊PID控制低压铸造液面压力适应时间短,产生的误差较小,效果较好。
Aiming at the problem of liquid pressure control of low pressure die casting equipment, there is a big error between the actual output pressure and the theoretical input pressure, which can not meet the needs of low pressure die casting equipment well. In view of this, a liquid pressure control system for low pressure casting equipment based on fuzzy PID control is proposed. First of all, introduces the schematic diagram of low pressure casting equipment, analysis of low pressure casting equipment liquid pressure control process. Secondly, the design of the liquid pressure control scheme, the use of fuzzy PID control to calculate the pressure control of gas flow in the process of change. Finally, the fuzzy PID control pressure tracking error is simulated and compared with the PID control method. The simulation results show that the adaptive time of LPF tracking is 2.0 s, the maximum error is about 12 Pa and the adaptation time of PID pressure control is 2.2 s. The maximum error is about 15 Pa. Adopting fuzzy PID to control the liquid surface pressure of the low-pressure casting has a short response time and less error, so the effect is better.