Research On Calculating Method Of High-speed Dynamic Measurement Of Time-grating Sensor

Time grating displacement sensor with own intellectual is a new displacement sensor.At present, the Time grating sensor has better precision and resolution when applied in thecondition of static and low speed measurement. However, it puts forward the newrequirements when Time grating sensor applies in the high speed dynamic measurement. Anumber of phenomena such as the regularity of sampling waveform is not obvious,waveform has the tip pulse, exist in dynamic measurement leads to dynamic errorsproduced and accuracy deteriorated. The research on problem, that exist in time-gratingdisplacement measuring in high speed dynamic mode, has important meaning of theoryand reality. It will drive the Time-grating industrialization forward.This paper carried out the research for the above questions, improving the dynamicperformances of Time-grating sensor, with the support of the National Science Foundationand the Defense Department.Firstly, making further analyze on the three methods of improving sensor’s dynamicperformance, and combing with Time-grating sensor’s measuring principle. We canincrease the number of dynamic measuring head in the measurement mechanism, use theclock multiplier and clock multi-phase for improve the resolution of time measurement onhardware, apply software interpolate subdivision method to experimental data processing.The method of software to improve the dynamic performance is focused researched andsoftware subdivision interpolation algorithm models are constructed.Secondly, the hardware circuit is designed in order to realize the software algorithmicmodel. The design of hardware circuit with FPGA as the core, mainly consist of A/Dsampling module, D/A conversion module, amplification, filter, display and USBcommunication module and so on. The high resolution A/D and the high speed computesystem are built.Then, we design the software for the software algorithmic models. the Time gratingsensor acquisition signal data is processed and analyzed by this means so that the systemachieves the time difference accurate measurement, and then reach the objective of highspeed dynamic displacement precision measurement.Finally, the test system is built to debug hardware and software. The experimentsshow that the hardware and software have reached design requirement and the systemsimplifies the data processing of hardware circuit and the program compared with traditional data processing method. At present, the signal frequency are increased from400hz to20KHZ, the measurement resolution can reach0.09"at the present stage.