Design And Test Of Real-time Monitoring System For Grain Moisture In Combine Harvester

Moisture content is an important factor in the production of grain.Real-time monitoring of water content has guiding significance for the classification of subsequent storage methods and quality.The moisture content of grain is also an important basis to judge the grain harvest period,real-time monitoring of water content for agricultural mechanization production.It has practical significance;real-time monitoring of water content is also an important part of the whole machine intelligence,and it is an important component of the production measurement system.At present,foreign real-time monitoring technology for grain moisture content is relatively mature,and large-scale combined harvesters are equipped with a production measurement system for real-time monitoring of water content.However,the existing real-time monitoring system for grain moisture content in China still has the problems of single monitoring object,poor monitoring accuracy and real-time performance.Based on the full investigation,this study carried out research on real-time monitoring system of grain moisture in combine harvester,and designed a real-time monitoring system that can be applied to a variety of grain measurement,high precision and good real-time performance.Based on the scraper lift combine harvester,a set of real-time monitoring system for grain moisture in the combine harvester was designed and tested.The main contents of this subject are as follows:(1)The mechanical structure design of the grain moisture real-time monitoring system of the combined harvester.It includes mechanical design of sampling mechanism,calibration test bench and sensor package structure,and trial production and mechanism debugging;(2)Moisture sensor hardware design The sensor hardware design mainly includes the design of the detection unit,processing unit and interactive communication unit,and tests the performance of the hardware detection,including the performance verification of the capacitance signal detection and the performance verification of the temperature signal detection.(3)The design,implementation and test of the software algorithm Calibration.The algorithm mainly includes the detection and processing of frequency signals and temperature signals.The calibration test mainly includes the calibration process,the analysis of the calibration test results and the establishment of the test model;(4)The verification test of the online monitoring system.Includes static model validation,bench dynamic verification,and field trials.The main research results of this paper are as follows:(1)The designed mechanical mechanism can realize real-time monitoring of sampling of various grain moisture,and the sensor is less affected by external interference;(2)The average relative error of sensor capacitance signal detection is less than1%,and the average temperature signal detection is The relative error is less than 0.5%.(3)The moisture detection model of wheat and rice is established.The coefficient of soil moisture function model is determined by R~2=0.9887,and the coefficient of rice moisture function is determined by R~2=0.9950.(4)The static verification of the wheat and rice models was completed.The root mean square error of the wheat and rice detection models was 1.74%and 1.37%,respectively.The dynamic verification of the test of the rice model was completed.The root mean square error of the measured moisture content was 1.84%;completed the field test of the rice model,the root mean square error of the measured moisture content was 3.48%.