Grain separation loss monitoring system in combine harvester

Based on laboratory experimental results obtained with an axial threshing test-rig with tangential feeding, cumulative distribution functions of separated grain in axial and radial directions of threshing rotor were built. Based on the analysis of the relationship between grain separation loss and grain separation flux in an area under the concave, an indirect grain separation loss monitoring method is presented in this paper.Piezo-electric polyvinylidene fluoride (PVDF) film was selected as sensitive material to design a grain flux sensor. While grain and material-other-than-grain (MOG) separated in the monitoring area impact on piezo-electric PVDF films, different electric charges are generated. After signal progressing with a charge amplifier, frequency discrimination and wave shaping, the number of grain can be counted by a microcontroller (MCU) and the grain separation loss of combine harvester can be measured in real-time.Field test results indicated that the measurement errors of grain separation loss recorded by the monitoring system relative to the loss checked manually were less than 12%.

Graphical abstractBased on the analysis of the relationship between grain separation loss and grain separation flux in an area under the concave, the papered present an indirect grain separation loss monitoring method and developed the measuring device. Laboratory and field experimental result show that it can monitor the grain separation loss real-time with a good accuracy. The device is potentially to be applied to some middle and small combine harvesters.Use the developed device to monitor the grain separation of combine harvester.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We model distribution functions of separated grain in axial and radial directions. ► Develop a grain flux sensor which could discriminate free grains from MOG. ► Propose a real-time grain separation loss monitoring method in combine harvester. ► Field test the feasibility of the grain separation loss monitoring system.