基于LabVIEW的扫描探针显微镜PID控制系统的设计与优化

Developing and Optimizing of Scanning Probe Microscopy PID Control System Based on LabVIEW

根据数字PID控制理论和SPM系统的反馈控制要求,研制了基于虚拟仪器的数字PID反馈控制系统。该系统被用于显示样品形貌,同时还作为反馈系统的输入信号,通过计算机LabVIEW程序中各种控制算法算出控制量,再经过D/A接口输出即可实现对控制对象的控制。各种控制算法只要改变LabVIEW程序就可实现,具有很大的灵活性。系统控制精度高、抗干扰强,而且结构简单、配置灵活,从本质上提高了SPM系统的性能。该模型用MATLAB SIMULINK进行分析。仿真结果表明,对于该系统,采用积分常数0.001,因此比例放大倍数不超过8.5为宜。

According to the theory of digital PID control and requirement of feedback control of SPM system, the thesis developed a digital PID feedback control system of scanning probe microscopy based on virtual instrument. This system was applied to display sample appearances, and was taken as input signals of feedback system. The system figures out controlled quantity through various control arithmetic in LabVIEW program in computer, and imports through D/A interface to realize the control on the target. So long as to change LabVIEW procedure, various control algorithms can be realized, with great flexibility. The system has high control precision, better anti-jamming, and simple structure, agile configure, and enhanced the performance of SPM system in nature. This model was analyzed with MATLAB SIMULINK. The simulate results indicate, according to commonly used platform of SPM, constant of integration that adopted is 0.001, and linear amplification no better than 8.5 is appropriate.