Development And Implement Of A Speed Measurement Module Based On FPGA

With the continuous development of the aviation industry, there is an increasing performancerequirement to the flight control system, as the key equipment in the hardware-in-the-loop simulationof flight control system, the performance of flight table directly influence the confidence of thesimulation results. Therefore, it’s great significance to develop high-performance flight table for theflight control system simulation.In this paper, a four-channel speed and position measurement module is designed based onFPGA, mainly to improve defects of existing flight table in the laboratory, such as poor low-speedperformance. Firstly, on the basis of analyzing a variety of speed measurement methods, the corespeed measurement algorithm is designed by using fixed sampling period M/T method. To solve theproblem of speed measurement’s dead zone, i.e. the speed value couldn’t be achieved under ultra-lowspeed, an improved method based on estimate and extrapolation is applied and implemented.Secondly, according to the speed measurement algorithm, the hardware design of speed measurementmodule is completed based on FPGA, and the logic function of speed and position measurement isimplemented by VHDL, as well as the interface functions of serial port, dual-port RAM and PCI, tomeet the data tranmission requirements of different types of controller. Then WDM driver programfor PCI interface under WindowsXP operation system is developed, and speed measurement softwareis designed and developed to achieve functions of data preservation, data processing and real-timedisplay.Through lots of test validity of different velocity under low-speed and ultra-low speed, speedmeasurement percision and performance stablity of speed measurement module all fulfilledrequirement of design specifications，thus confirmed the coeerctness, reasonableness and feasibility ofthe design scheme of speed measurement module.