Development of rapeseed cleaning loss monitoring system and experiments in a combine harvester

To monitor rapeseed loss in real-time during the harvesting process, a rapeseed loss monitoring system based on the signal analysis of impacts, was developed. Firstly, to understand grain and MOG (material other than grain) collision signal characteristic, models for different threshed outputs components were established in the EDEM software, and the corresponding collision signal characteristic for different components were obtained, thereby laying the foundation for the design of a signal processing circuit. Secondly, using a P5-3B type piezoelectric ceramic as a sensitive element, a multi-block cleaning loss sensor and a signal processing circuit with amplification, filtering, rectification, comparison functions and early warning functions were developed. Finally, performance calibration tests with different grain flow rates, different rapeseed varieties and mixture were carried out in the laboratory. Calibration and field testing showed that the detection accuracy of the developed rapeseed loss monitoring sensor was high and the overall performance was acceptable.