Design And Implementation Of Signal Processing System Of Time Grating Based On SOPC

Displacement measurement is one of the most basic and common physicalmeasurement. Our research team has been study the magnetic field precision gratingdisplacement sensor has reached the international advanced level at present. Although thegrooving precision and density as well as the signal anti-interference ability of time gratingdon’t need to compared with grating, It still have the following disadvantages: first, thesignal using electromagnetic coupling form, which strength cannot furtherimprove;second,it need uniform slot on the motor or probe and the guide rail, but it islimited by the mechanical processing precision;recision;third, the sensor of the stator coiland induction coil matrix require the use of magnetic material,result the quality is heavier,and because the sensor technology need winding, the production efficiency is low.Aiming at the shortcomings of the existing technologies, a grating sensor based onalternating electric field has been invented. It is without a precise scribed line, and withoutresistance segment box. However it adopt differential plate capacitive structure and electricfield coupling theory to collect signal, with the displacement of the clock pulse asprimary standards of measurement, so it is low power consumption, light weight, highresolution and low cost. But the excitation signal and sensor signal frequency of such typetime grating displacement sensors are high, which is up to100times of the magnetic fieldgrating displacement sensor. Higher demands are put forward for signal processing. Howto improve the signal processing speed has become one of the key problems.Put the electric field time gating sensors signal of40KHz frequency as the researchobject in this article, research the traveling wave measurement signals generate mechanism,signal forming quality, control method and the signal processing technology based on thealternating electric field. Front signal conditioning circuit was designed and implemented,which greatly improve the stability of the signal. A signal processing system of timegrating based on SOPC technology is designed by researching the precision theory ofelectric field time gating sensors, error separation and correction technology. In thissystem, data collection and processing are integrated in a FPGA inside, which simplifiesthe circuit structure design and reduce the power consumption of the system. Theimplementation of the scheme and design method of the SOPC technology was introducedin detail. This design uses the Cyclone III EP3C25E144I7of Altera corporation as the main controller to realize the function on chip, using VHDL hardware description languageand its internal IP core in FPGA to realize the cycle counting, phase difference, datacaching, interrupt and so on, customize the Nios II directive, a time grating signalprocessing system based on Nios II soft core processor is constructed.The ultra-high precision electric field linear time grating sensor prototype wasdeveloped by our team and the signal processing system has been successfully applied tothe prototype. The measurement precision is better than±0.7, which has reached theinternational leading level.