Research On The Method To Improve The Accuracy Of The Data Acquisition System Of Micro-displacement Platform

Micro-positioning technology is one of the most important modern science technologies, the level of development represent the comprehensive economic and technology of a country, and it is an important symbol of national manufacturing technology. The future development of nanometer displacement and positioning technology are valued highly in developed countries. Data acquisition and processing system of micro displacement positioning technology is an important parts of the data acquisition system. To realize high precision micro displacement positioning, the high-precision data acquasion is very important.This topic contraposed the high precision displacement platform, high demandingness of data acquisition have proposed. The system of data acquisition of high precision displacement platform has been designed. The system was divided into four parts, digital processing module that is the core of DSP, analog-to-digital conversion module, digital-to-analog module. A signal was processed by DSP, which was received from capacitive sensor after digital-to-analog module received collection command from DSP after digital-to-analog module put analog signal into digital signal. The clock signal and control signal of digital-to-analog module and analog-to-digital conversion module were provided by DSP, the signal was also analyzed, stored, processed by it, and the actuator was driven by the analog signal processed with DSP, finally to complete the positioning of the micro displacement platform.In order to improve the accuracy of data acquisition, four aspects have been used to save this problem in the design. One is the analysis of the error of the hardware and the aperture jitter. In the hardware error analysis, the relationship between the voltage gain and error were calculated. The second is the design of the filter, including the analog filter and digital filter. Analog filter including the active filter and passive filter circuit design. The appropriate filter has been chose to fit this system with a simulation tool in the Matlab filter box. The third is the design of hardware circuit, including analog-to-digital conversion and digital-to-analog conversion circuit. The circuit layout and wiring appropriate can also improve work condition of the circuit and the accuracy of data acquisition. The power module, amplifier circuit design, and the reference voltage circuit design are important in the design of PCB board. The last is signal integrity analysis, after the circuit design was completed. The Hyperlynx software was used for the simulation study of reflection and crosstalk problems of the master clock signal. The terminal technology was used for saving the signal integrity problem. Source end cascading termination resistor and remote end termination resistor and capacitor methods were adopted to weaken the reflected signal, the reflection peak of clock signal could be weakened form 4.7 V to 3 V. By applying terminating 100? resistor, shorten the length of the transmission line and reduce the distance of the adjacent network could weaken crosstalk phenomenon from 4.4 mA to 2.5 mA.Eventually be able to achieve high precision data acquisition.