Design And Experiment Of Yield Monitoring System For Rice Combine Harvester

The yield monitoring of grain combine is an important link of precision agriculture,which plays a decisive role in the construction of green,efficient and economical field agriculture in China.The yield monitoring technology is limited by the existing measurement methods,and the average error of the yield monitoring system cannot be less than 2%.At the same time,there are few researches on photoelectric yield monitoring technology in China,and there is a huge gap in the industrialization development of yield monitoring technology with foreign countries.In this context,two objectives of this project were proposed: 1.Using the new measurement technology,the 3D point cloud was applied to the measurement method of grain volume to further reduce the average error of yield measurement;2.Using photoelectric sensor to develop yield monitoring system,and the average error of the system in the field yield measurement reaches the level of the current commercial yield measurement system.In this paper,in order to realize the yield monitoring of the actual field operation of the combine harvesters,a yield monitoring method based on duty cycle measurement is proposed in this paper.Based on this method,a yield monitoring system is designed and developed by using a photoelectric sensor.On the basis of hardware and software development of the system,the grain stacking shape was analyzed by using EDEM simulation,and the theoretical model of grain stacking was obtained.The direct proportional function relationship between the measured duty ratio and grain weight was deduced through the theoretical model.Finally,the global model and the local model were obtained by fitting the measured data from the bench test.In the process of software design,the method of yield diagram construction is studied.This paper presents an array-dependent yield data filling method without relying on the API interface.Firstly,the field area was gridded,and the relative displacement of GPS coordinates during the operation was used to generate the track map of the grain combine harvester.Then,based on the trajectory,the yield data is added along the trajectory and the array is filled with the data by step distance.Finally,the grid array is visualized by continuous color.The key data for the yield chart construction are obtained through the third-party yield monitoring system.Based on the data set,the software of yield chart construction is designed.The software can realize the function of generating the vehicle track map,the moisture distribution map of the operation process,the wet yield distribution map and the dry yield distribution map of grain.Finally,in order to verify the performance of the yield monitoring system,bench test and field test were carried out.Bench tests were carried out to verify the global and local models.The results show that the yield monitoring system in this paper has great uncertainty in measuring smaller grain weight.However,in monitoring the yield of larger weight grains,the accumulated errors of the system can be averaged to obtain high accuracy.In the field test,the scraper signal under no load and the abnormal signal in the yield were studied respectively.Among them,the probability of abnormal signal in the yield monitoring system in this paper was 1.12%,which may come from the sliding grain in the granary,the impurities in the grain and the vibration of the fuselage.After modifying the fitting function of measuring data and weighing data,the performance of the yield monitoring system was verified.The results show that the maximum relative error between the measured value and the actual weighing is 3.83%,and the average error is1.84%,which reaches the level of the foreign commercial yield monitoring system.