Design Of Micro-displacement Controller For Z Axis Of Microscope Objective

The fluorescence microscopy is one of the main methods for cell biology and biophysics research. Further research of the exocytosis and cellular process is not only helping us to understand the mechanism of cells'activities but also providing diseases'cure and therapy. With the improvement of the fluorescence microscopy and fluorescent probe, direct observation of the vesicles'trafficking and exocytosis has become popular. In recently years, the Institute of Biophysics and Biochemistry of Huazhong University of Science and Technology has put forward deconvolution algorithm to acquire the intracellular and transmembrance cargo transportation by vesicles. However, this method has its disadvantage. It could only record the movement track of the vesicle within a very limited scope. To improve this, the new method of single-particle tracking in active cells is applied.Z axis micro-displacement controller is an important sector of fluorescent microscopy. And for Z axis driver, employing piezo-based micromanipulator is able to ensure the steadiest performance. In order to meet the needs of experiment control and system security, a set of Z axis positioning control is designed. This system is divided into the voltage regulator, driver, MCU control and software control.The DC regulated power supply consists of separate devices and integrated circuits, which is based on LM317 suspension structure, and the current-limited circuit is also included. Driving circuit produces continuous adjustable voltage output from 0 to 115V by employing the structure of a normal operational amplifier driving a power MOSFET. To improve the displacement accuracy and linearity, the closed loop control part that is based on proportion integral circuit is used. The displacement sensor was accomplished by LVDT, which converts the displacement into the voltage signalThe part of MCU control firstly used the SST89E516 and encoder to accomplish the transform from input code signal to voltage output, and then the entire programme has been transplanted to EZ-USB FX2 with USB protocol. This achieves communication between the PC and controller communication.