Development Of Online Monitoring Device For Grain Flow Based On Laser Array

Online monitoring of grain flow is the key link to obtain grain yield information.By studying the differential distribution of grain yield and the input of agricultural production materials,it is helpful to analyze the effects of different agricultural production materials on crop growth,which is not only the representation of the current management efficiency of farmland operations,but also a decision-making basis for the next round of accurate management of farmland operations.At present,the grain flow monitoring system has become a standard accessory for large foreign combine harvesters and has good performance.However,the domestic research on grain flow monitoring technology started late and is still in the experimental stage.The foreign grain flow monitoring system is mainly used on large combined harvesters and it is very expensive,which is not suitable for the introduction and use of small and medium-sized harvesters in China.The existing grain flow monitoring system of the combine harvester with the scraper type grain transport device in China mainly uses a single infrared light structure,which cannot completely characterize the irregular distribution of grain information on the scraper.In view of the above situation,this thesis designs an on-line monitoring device for grain flow based on laser array to realize real-time monitoring,display and storage of grain flow related information.The main research contents and results of this thesis are as follows:1)Hardware design of on-line monitoring device for grain flow based on laser array.The overall scheme design,sensor fixed bracket design and measurement circuit design were carried out according to the factors that affect the performance of grain flow on-line monitoring device of laser array.The on-line monitoring device is mainly composed of laser sensor,speed sensor,GPS active antenna and GPS module,scraper feeder lift speed sensor and forward speed sensor signal processing circuit,GPS module signal processing circuit,CAN communication circuit and display module.In particular,the arrangement of laser array is designed.In order to obtain the laser array with the best grain distribution,four different laser arrays were selectedand the single factor volume measurement test were carried out.2)Research on grain flow monitoring method based on laser array.In view of the difficulty in measuring the grain flow caused by the uneven distribution of grain in the scraper type grain transport device and the analysis of the grain flow monitoring method and the monitoring principle of laser sensor,this thesis presents a method of grain flow monitoring by using the laser array.The method uses the principle of stratified integration to convert the grain volume measurement into a signal measurement of the laser array and the elevator speed sensor,and calculates the grain quality in combination with the grain bulk density.In order to study the grain distribution in the scraper type grain conveying device,the EDEM discrete element simulation analysis software was used to simulate the rice grain accumulation,and the rice particle stacking angle was measured by MATLAB software to obtain the volume compensation parameters.3)Software design for on-line monitoring device of grain flow based on laser array.According to the design requirements of the device function,the software design of the grain flow online monitoring device based on the laser array is designed.The system software design mainly includes: main program,speed acquisition and processing program,parameter setting program,flow data acquisition and processing program,positioning information receiving and analyzing program,LCD display program and CAN communication program.Among them,the speed acquisition and processing program realizes the collection of the forward speed of combine harvester and the lifting speed of scraper grain conveying device;the parameter setting program realizes the setting of the grain bulk density information.4)Performance test of grain flow on-line monitoring device based on laser array.On the basis of completing the software and hardware design of grain flow on-line monitoring device and the research of monitoring method of grain flow,the design of grain flow calibration test bench for the scraper type grain conveying device was carried out,and the indoor bench test was carried out.The bench test results show that the relative error of the elevator speed sensor measurement results is less than or equal to 2.00% under the no-load operating conditions of the test bench.When the grainmoisture content is the same,the relative error of grain flow online monitoring device based on laser array is less than or equal to 4.00%.Under the condition of bench test,the on-line monitoring device of grain flow based on laser array can achieve grain flow on-line monitoring and display,which provides technical support for on-line monitoring of grain flow and on-line measuring yield of combined harvester with scraper type grain conveying device.