Design And Research Of Ultrasonic Liquid Flowmeter System

Ultrasonic flowmeter is a new style of contactless and intelligent flowmeter,which has the virtue of broad adhibition range,low fabricateing expenditure,great precision,fairly strong surroundings resistance and the like.This paper designs an ultrasonic liquid flowmeter which uses the improved time of flight diffraction to measure,and put forward a way of supersonic signal noise elimination which unites small wave packet decomposition preconditioning and EEMD algorithm,which can validly increase the precision of supersonic system measurement.The prime work of this paper is as follows:1.This thesis uses the time of flight diffraction after bring forth new ideas and perfection integrate with ARM chip STM32F407 as the centre to carry through the circuit devise of related computer hardware segment,Contain ultrasonic sending circuit,receiving circuit,display module,power module,serial port module and Functionality come true based on STM32F407 digital chip.The good velocity A/D inverter unit built in the microcontroller is used for analog-to-digital conversion of the echo signal after signal administration.Then through the project of the correlative logarithmic operational amplifierss electrocircuit and bandpass filter electrocircuit to accomplish the amplification and filtering of ultrasonic echo signal.2.Design the relevant part of the software of ultrasonic flowmeter,and add digital filtering technology to the software program,which can not only overcome the interference caused by various random errors but also reduce the hardware cost.Keil Vision5 software was used to develop and debug the software part of the ultrasonic flowmeter.Modularization parts was implement,with the major routine as the major body,and the measurement module and import and export die block were named to come true the feature of the ultrasonic flowmeter.3.This thesis bring forth new devises designs an ultrasonic signal diminution unpitched sound way integrating small wave packet resolvtion predecomposition and EEMD algorithm.The simulation analysis of the studied algorithm is carried out in MATLAB software through experiments.The experimental results show that the method combined with wavelet packet and EEMD decomposition is better than the single EEMD decomposition for noise reduction,which demonstrate that the wipe out unpitched sound algorithm designed in this thesis is realistical and resultful,and can increase the precision of the measured parameters.4.Analysis of experimental results.In this paper,through the actual research and progress of flowmeter with normative property of doppler flow gauge survey test information,the laboratorial consequences reveal that this thesis the design of the ultrasonic flowmeter velocity measurements of absolute error less than 10 mm/s,the correlative deviation is be short of 2%,to verify the design of the ultrasonic flowmeter with qualified performance and accuracy requirements.