Diagnostic features for the condition monitoring of hypoid gear utilizing the wavelet transform

The present paper contributes to the development of new efficient solutions aimed at improving vehicle functional safety through the implementation of new transmission diagnostic methods. The study focuses on a new perspective of the diagnostic frequency range for hypoid gear condition monitoring, using acoustic emission and vibro-acoustic signal measurements and the Discrete Wavelet Transform for data analysis. The identification of the most sensitive diagnostic parameters and determination of frequency intervals using the Discrete Wavelet Transform, in which the most significant increase in the values of diagnostic parameters can be seen, has been presented. In addition, the identification of the sensitivity of the above-introduced non-destructive methods is presented. Diagnostic results in the extended frequency range were compared with the results of the classical method, and it was found that the selected parameter in the proposed measuring range could better characterize the condition of the gear unit.     

Stochastic Dynamic Aircraft System Conflict Distribution under Uncertainties

A dynamic aircraft system conflict (concurrent event) situation exists when a time with a loss (-es) of separation (LOS) in their true or predicted trajectories is determined. Regional air traffic management (ATM) programs aim to make ATM safer and more efficient through a higher level of automation for such processes as dynamic aircraft systems concurrent events detection and, consequently, resolution. Therefore, wind and aircraft speed uncertainty parameters should be properly addressed. This paper offers an approach to a dynamic aircraft system flying under a certain concurrent event situation and demonstrates situation stochastic distribution results (output) based on determined wind speed values (while wind direction angles and the dynamic aircraft system speed values are random). Based on these facts, the stochastic dynamic aircraft system conflict distribution information under determined and random parameters might be retrieved at any specific (preferred) time moment. The observations of this study disclosed that such stochastic output data might have a certain impact on safety matters (potential “domino effect” conflicts on a horizontal plane) and on the efficiency (i.e., flight distance which eventually is a determinant of flight time, fuel costs, delays, emissions, monitoring, etc.).