Linearization outcomes of static characteristic of an ultrasonic transducer measuring the parameters of fiber materials

Abstract

It is known that the quality of semi-finished products and products made from fiber raw materials depends on the physical and mechanical properties of the materials used. Currently, fiber raw materials are processed on high-speed units using continuous process technologies with a minimum number of transitions. Such technologies are possible with automatic control of unit operation and automated express control in order to ensure the performance of processed products (tapes, threads) with a given weight (number) and the minimum allowable unevenness (quadratic unevenness). The prospect of solving these problems through the use of ultrasonic acoustic sensors is discussed. The research goal is to make a comparative analysis of the linearization of the static characteristic of the electroacoustic piezoelectric transducer and select the basic scheme that provides the minimum static error. We approximate the input static characteristic of an ultrasonic sensor by an exponential polynomial, on which basis its advantage in comparison with the logarithmic linearization method is justified. Two structural schemes of linearization of the static characteristic of an ultrasonic sensor are studied: correction using a logarithmic amplifier, and correction using a functional generator. Without linearization, the coefficient of amplification varies from 6.1 to 0.4 V kTex, and the relative error reaches 110%. The logarithmic scheme does not provide linearity: coefficient of amplification deviations range from -36% to +61% relative to the average value of 3.1 V kTex. The proposed scheme with a functional generator stabilizes the coefficient of amplification at the level of 3 V kTex with deviations not exceeding the error of the measuring path. The results obtained may be used in the modernization of automated quality control systems for fiber raw materials at enterprises of the agro-industrial complex.