Design And Realization Of Sunflower Combine Harvester Yield Measurement System

Yield measurement system,as an intelligent equipment in modern agricultural machinery,provides powerful help for agricultural production and management by obtaining yield information of crops in the field.The existing harvester yield measurement system mainly obtains the information of grain quality,working area and geographical location when the combine harvester works in the field,so as to realize the measurement of crop yield.Among them,the collection and acquisition of grain quality is mainly used to measure the grain quality of auger type and scraper type grain conveying device by impulse sensor,but the grain flow of pneumatic grain conveying device has not been studied yet.In order to realize the automatic measurement of yield of pneumatic sunflower combine,the following work has been carried out in this thises:(1)Design of yield measurement system of sunflower combine harvester.Aiming at the sunflower combine harvester,a test bench was designed for the transverse warping conveying and pneumatic conveying parts of the harvester.Impulse sensor is installed in the outlet position of pneumatic conveying structure to obtain reliable grain impact information.The Beidou dual-mode positioning system was selected with a positioning accuracy of 2mm to obtain the traveling speed and real-time positioning information of the harvester.(2)Simulation test of impulse sensor.The strain and displacement of the impulse sensor are determined by the stress and strain analysis.Modal simulation analysis is done for the second order sensor system to determine the influence of impact plate material and impact plate installation position on the natural frequency and formation of the system.Through the first six natural frequencies of the impulse sensor system,the harmonic vibration analysis is done,and the frequency range of possible resonance of the system is determined.(3)Analyze and process the impulse sensor signal in the production test.Using wavelet threshold method to eliminate the noise signal,according to the voltage impulse sensor information to extract the vibration noise of feature selection suitable wavelet base and the decomposition scale is determined,choose appropriate calculating signal threshold function way,determine the reasonable way of signal threshold denoising,after multi-scale decomposition for the high frequency components in the signal filtering,low frequency interference using threshold processing,has been improving the measuring accuracy of impulse sensor.(4)Test bench test and field test.The material and position of the impact plate of the impulse sensor were determined and verified by the test bench calibration test.The test bench calibration of sunflower grain weight,sensor voltage and velocity was carried out.The field experiment error was less than4.25% by referring to the two-element function model.