Evaluation method of diagnostic signal informativeness

Abstract

© 2019, Institute of Advanced Scientific Research, Inc.. All rights reserved. Modern requirements for the operation of cars lead to the need to improve the efficiency of their maintenance. Diagnostics, as an element of the maintenance process, occupies one of the leading roles, making it possible to provide information on the technical condition of a particular element at different stages of operation. Due to this, it is possible to respond in a timely manner to a change in the technical condition of a diagnostic object with minimal resources. In this paper, we consider the diagnostic signal of a car gearbox, which in most cases is a discrete periodic function. Assessing the information content of such a function is an urgent task, especially when it is necessary to compare the effectiveness of various methods of this function processing or evaluate the effectiveness of the selected diagnostic method. Today, there are the methods for a diagnostic signal evaluation. This is the calculation of information amount for various states of the system and the method based on probability density comparison of diagnostic signals for the possibility of their “overlap”. These methods require good a priori data obtained experimentally, but in most cases this is difficult. In addition, the method of probability density comparison does not correctly reflect the information content of a signal, which is a periodic function. In this paper, the information content of the diagnostic signal was presented as the reciprocal of the Hartley amount of information. The uncertainty associated with a diagnostic signal consists of the uncertainty of an informative signal receiving and a defect detection. The essence of the method is to obtain the correlation function and its excess coefficient, with known characteristics of the function that describes the manifestation of the defect, because the excess coefficient is associated with the information content of the diagnostic signal. The method allows you to give a relative assessment of the information content of the diagnostic signal. Evaluation of the proposed method was performed on the diagnostic signals of the gearbox with varying degrees of the defect development, as well as on the diagnostic signal processed by two methods.