Improving the Process of Vehicle Units Diagnosis by Applying Harmonic Analysis to the Processing of Discrete Signals

The article discusses the features of designing a diagnostic system in which harmonic analysis is used to improve the quality of diagnostic information processing. The cyclic analog signal coming from the sensor and containing the diagnostic information is converted into a discrete signal. Accumulation of diagnostic information processed by equipment is carried out in the form of discrete signals. The processing and analysis of the obtained diagnostic information is carried out by applying harmonic analysis. Periodic processes of operation of vehicle units are associated with the occurrence of noise and vibration having a different frequency but related to the same node. A feature of the presented system is that it uses a contactless method of obtaining diagnostic information about the operation of vehicle units. The system calculates the speed of the node, measures the noise level and calculates the level of vibration that occurs during its operation. The article shows the results of experimental studies on the determination of vibration in vehicle nodes. Found relationship between the occurrence of noise and increasing the level of vibration of the node. The algorithm for the refinement of the harmonic analysis result is formalized, which makes it possible to eliminate the crude unpredictable error caused by the sampling of the analog signal. The application of pre-filtering algorithms analog signal from the sensor used to reduce the overall level of noise spectrum is substantiated. The article describes the structure of the diagnostic system allowing to determine the vibration level of rotating nodes. The use of harmonic analysis in the diagnostic system, in the conditions of a limited amount of diagnostic information, reduces the error in determining the amplitude of the vibration signal by 15-50%.