基于FPGA的表面形貌干涉测量中的控制方法研究

发布时间：2018-05-04 03:33

本文选题：表面形貌测量 + PZT驱动　；参考：《湖北工业大学》2015年硕士论文

【摘要】：在精密测量、航空航天、生物医学、电子制造等领域,高精度、自动化微表面形貌测量具有重要的意义。近年来已经有很多基于光学测量微表面形貌的方法被提出,应用较为普遍的有白光相移干涉技术、传统相移干涉技术和多波长干涉技术等,本文围绕波长轮换与相移扫描相结合的表面形貌干涉测量系统,研究了该系统中的运动控制和图像采集控制,并基于FPGA予以实现。主要研究内容如下:首先论述了基于波长轮换与相移扫描相结合的干涉测量系统的原理,基于FPGA实现压电陶瓷的驱动进行相移,上位机与FPGA利用串口RS232进行通信。首先,由FPGA发送出方波信号经D/A转换输出模拟量,然后通过积分放大电路驱动压电陶瓷(PZT),整个驱动在开环的控制方式下进行,最后通过椭圆拟合算法原理算出PZT驱动步距。其次,设计了波长轮换系统。基于FPGA驱动步进电机,带动装有滤光片的圆盘转动,从而实现波长轮换,并基于Labview编写了上位机程序,对PZT和波长轮换进行有序控制。第三,阐述了二维工作台的驱动方法,二维工作台在X轴和Y轴分别通过一个步进电机与精密丝杠配合驱动,并通过光栅尺反馈的信号进行准确定位。最后,论述了波长轮换机构、PZT驱动、二维运动机构和图像采集的同步控制。通过三个模块的协同控制实现每驱动PZT一个周期,控制波长光源轮流切换一次,同时通过FPGA的I/O外触发CCD,在PZT每驱动一步采集相应的干涉图像,将采集到的干涉图像保存到计算机上,并通过二维工作台的移动实现更大范围的测量。
[Abstract]:In the fields of precision measurement, aerospace, biomedicine and electronic manufacturing, it is of great significance to measure micro-surface topography with high precision and automation. In recent years, many methods based on optical measurement of micro-surface morphology have been proposed, such as white light phase-shift interferometry, traditional phase-shift interferometry and multi-wavelength interferometry, etc. In this paper, the motion control and image acquisition control of the system is studied, which is based on FPGA. The main research contents are as follows: firstly, the principle of interferometric measurement system based on wavelength rotation and phase shift scanning is discussed. The drive of piezoelectric ceramics is realized based on FPGA, and the upper computer communicates with FPGA by serial port RS232. First, the square wave signal is transmitted by FPGA through D / A conversion, and then the piezoelectric ceramic PZT is driven by an integral amplifier circuit. The whole drive is carried out under the open loop control mode. Finally, the PZT driving step distance is calculated by the ellipse fitting algorithm principle. Secondly, the wavelength rotation system is designed. Based on FPGA, the stepper motor is driven to drive the disc with filter to realize wavelength rotation. Based on Labview, the upper computer program is written to control the rotation of PZT and wavelength in an orderly manner. Thirdly, the driving method of the two-dimensional worktable is expounded. The two-dimensional worktable is driven by a stepping motor and a precision lead screw in the X axis and Y axis respectively, and the accurate positioning is carried out by the feedback signal of the grating ruler. Finally, the synchronous control of PZT drive, 2D motion mechanism and image acquisition of wavelength rotation mechanism is discussed. Through the collaborative control of the three modules, each driving PZT cycle is realized, the control wavelength light source is alternately switched once, at the same time, the CCDs are triggered by the I / O external of FPGA, and the corresponding interference images are collected at each step of the PZT driver. The interference images are saved to the computer, and a larger range of measurement is realized by the movement of the two-dimensional worktable.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TP274;TN791

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