Research On Accuracy Of Grain Yield Sensor In Combine Harvester And Filed Experimentation

Crop yield information acquisition is an important part of precision agriculture.In this paper,according to the measurement system,developing the experimental platform based on the CF703 combined harvester,the software is used to complete the message analysis,signal processing,the calculation of the harvest area and the real-time display of yield distribution map,and field experiments were carried out to analyze the experimental results of different plots.The main research contents are as follows:(1)Build yield measuring system experimental platform,carrying out the design and installation of parallel beam sensor,digital transmitter,embedded industrial control computer,touch screen and GPS device,and using VC++ to parse message of production message analysis signal and GPS positioning signal,the digital signal value and the location information of the harvester were obtained.And a variety of the algorithm of eliminating noise and vibration interference is used to process digital signal.Designing the MFC interface of the host computer is used to control the GPS differential system,calibrate the yield,enter the number of plots and display status information,etc.(2)In order to improve the estimation precision,in the case of no-load test,using different working conditions to compare output signal and digital signal of adaptive interference cancellation with the ANC algorithm based on dynamic parameter correction,it is found that the ANC algorithm based on dynamic parameter correction is superior,and noise removal effect is better.At the same time,studying the influence of different cutoff frequency of FIR low-pass filter on the noise removal effect,and conducting reducing cutoff frequency test,comparing output signal and digital signal of different cutoff frequencies,it is concluded that the most suitable cutoff frequency for the experimental platform is 40Hz.(3)Conducting yield the calibration experiment,and obtaining the calibration coefficient of the land,No.1116,No.1117 and No.1118 of these three plots were measured yield production experiment,the real-time rendering of the yield distribution map is realized.And through the experimental comparison and research shows that the highest yield plot is No.1116 and the output precision is the smallest,and the instantaneous output is the smallest.However,yields of No.1117 and No.1118 are close,which accuracy and the beat amplitude are too large,and the measurement error is less than 7.4%.And it is found that the amplitude of instantaneous yield is big which has something to do with grain outlet structure of harvesting machine.(4)Studying harvest area measurement,combining additive method based on dynamic coefficient modification with irregular polygon coordinate method was used to calculate the area,and then the area of the plot was obtained.At the same time,the area measurement experiment was carried out in the process of production experiment,and the measurement error of the harvested area was kept within 10%,basically meeting the operation requirements of harvesting machinery.