Modelbased signal processing of a combine harvester

Nowadays, commercial mass flow sensors are already available on combine harvesters. The corresponding signal together with the machine velocity, cutting width and position within the field, provide essential information for constructing grain yield maps. Since the grain flow sensor is installed at the end of the threshing mechanism, the acquired signal and by this the constructed yield maps, are significantly disturbed by the dynamic impact of the machine. A description of the harvester dynamics is obtained by constructing an analytical grain flow model, based on the connection of experimental section models. Due to interesting properties of some of these section, the total model can be approximated by a linear combination of 2 time shifted signals and a linear transfer function describing the smearing impact of the mechanism. The application of an appropriate low pass filter, removing the high frequency content from the signal and the inverse linear model, an optimal compensation for the machine dynamics is found, easy to implement in both analysis or acquisition software.