This PhD thesis concerns the vibro-acoustic monitoring of the threshing process in an axial flow harvesting machine. This research is a step towards the development of online control systems finalized to maximize the process efficiency and the product quality. By using different signal processing tools it is possible to analyse the link between sound/vibration and material distribution in the threshing unit. In more details, the threshing process is mainly given by two principal mechanisms: the threshing between kernels and concave and “grain over grain” effect. The goal of this research is to use vibroacoustic signature in order to interpret in detail these two mechanisms of the threshing process. In particular, they have been explained by means of the cyclostationary approach useful to evaluate the first and second order cyclostationary contents of the signal. Moreover, the presented results show that some features obtained from the time and angular domains and from the cyclostationary approach are well correlated to the efficiency and operational parameters. Thus, they could be used for the development of an online control system.
Monitoring of the threshing process quality by using advanced vibro-acoustic indicators
FIORATI, Stefano
2011
Abstract
This PhD thesis concerns the vibro-acoustic monitoring of the threshing process in an axial flow harvesting machine. This research is a step towards the development of online control systems finalized to maximize the process efficiency and the product quality. By using different signal processing tools it is possible to analyse the link between sound/vibration and material distribution in the threshing unit. In more details, the threshing process is mainly given by two principal mechanisms: the threshing between kernels and concave and “grain over grain” effect. The goal of this research is to use vibroacoustic signature in order to interpret in detail these two mechanisms of the threshing process. In particular, they have been explained by means of the cyclostationary approach useful to evaluate the first and second order cyclostationary contents of the signal. Moreover, the presented results show that some features obtained from the time and angular domains and from the cyclostationary approach are well correlated to the efficiency and operational parameters. Thus, they could be used for the development of an online control system.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
