基于遗传算法改进的电子束蒸发系统PID控制实现

PID Control of Electron Beam Evaporation System Based on Improved Genetic Algorithm

依据电子束蒸发系统的晶振探头采集沉积速率,通过晶振膜厚控制仪的输出电压控制电子枪灯丝两端电压,从而调整电子束的输出功率.根据沉积速率的变化,采用遗传算法中的PID闭环反馈控制改变灯丝电压,达到稳定沉积速率的目的.实验证明,利用该方法研究其在电子束蒸发过程中速率控制的算法进行蒸发,可以使实验用镀膜生产使用的SiO_2膜料表面保持一定平整度,并且得到较稳定的蒸发速率.其他镀膜系统以及不同镀膜膜料可依据该算法适当修改参数,即可改善沉积速率的控制效果.

According to the deposition rate collected by the crystal probe of the electron beam evaporation system,the output voltage of the crystal film thickness controller is used to control the voltage at both ends of the filament of the electron gun,so as to adjust the output power of the electron beam.According to the change of deposition rate,the closed-loop feedback control of PID in genetic algorithm is used to change filament voltage to stabilize deposition rate.Experiments show that by using this method to study the rate control algorithm in the process of electron beam evaporation,the surface of SiO2 film used in the production of experimental coatings can maintain a certain smoothness,and a relatively stable evaporation rate can be obtained.Other plating systems and different coatings used can be modified by appropriate parameters according to the algorithm,which can greatly improve the rate control effect.