The Method Research Of High Precision Ultrasonic Displacement Measurement

Ultrasonic displacement measurement as a non-destructive measurement method is applied more and more widely.Especially,the ultrasonic has good penetrability and does not damage the characteristics of the measured object,so that ultrasound has unique advantages in special displacement measurement occasions such as thickness and so on.However,due to the influence of ultrasonic characteristics,such as the propagation speed of ultrasonic waves under different temperatures and different materials is different,the ultrasonic attenuation in media is easy,so the accuracy of ultrasonic displacement measurement is not high.In order to improve the accuracy of ultrasonic displacement measurement,the cost and complexity of the system will also increase.The several predecessors' high-precision ultrasonic displacement measurement methods are summarized and the advantages and disadvantages of previous methods are analyzed on this topic.Then,a new method is proposed on this topic.The innovation of this method lies in changing the measurement of ultrasonic displacement into frequency measurement,and the use of PLL stable the frequency of output signal,so that further improve the ultrasonic displacement measurement accuracy,and it also solve the technical bottleneck of difficult to improve precision of measurement of ultrasonic displacement,and further reduce the cost.The basic principle of ultrasonic wave is analyzed primarily on this topic,according to which the corresponding ultrasonic probe is selected,and each hardware circuit is designed.The hardware circuit consists of a keyboard input circuit,an ultrasonic transmission circuit,an ultrasonic receiving circuit,a signal processing circuit,a phase-locked loop circuit,a speed calibration circuit,and a liquid crystal display circuit.This subject focuses on the design and analysis of ultrasonic transmitter circuits and phase-locked loop circuits.First,the circuit parameters are designed preliminary by simulating each circuit.Then each circuit is tested separately to further optimize the design of related parameters and the selection of related chips.Finally,through the result of measurement of small steel plates of different thicknesses,the theoretical and practical resolutions are analyzed and calculated,and the causes of measurement errors are analyzed to further optimize the subject.This method has the advantages of simple structure,low cost,and easy to achieve high accuracy.It has wide application prospects in small displacement measurement,especially in high-precision displacement measurement such as thickness measurement.