Design And Experimental Study Of Yield Measurement System For Maize Plot Breeding

Maize is an important cereal crop in China,and it plays an important role in feed,food and industrial production.The quality of maize breeding determines the yield and quality of maize.Aiming at the problems of high labor intensity,disordered data recording and high price of imported equipment,a fast and convenient maize plot yield measurement system is designed.In this paper,a capacitive moisture sensor is used to measure the moisture content of maize.Two thin copper foils are embedded in the gap between the barrel body and the slot reserved for the central axis.The capacitive moisture sensor can be combined with the discharging barrel.It can not only measure the moisture content of the production system,but also discharge the samples from the grain box.It is a new type of capacitive moisture transmission.Sensor structure.The rotating barrel,together with the weighing:grain box,quadrangular weight sensor and temperature sensor,constitutes the mechanical structure of information acquisition,and designs the test circuit and control system.The designed yield measurement system can accomplish the collection and storage of com grain sample weight,moisture,bulk weight and per mu yield data in a"one-button" manner.The main research work includes the following aspects.(1)Structure design of maize plot breeding and yield measurement system.The sliding friction angle test was completed.Torque measurement test was completed,and it was found that the rotating barrel’s rotating torque ranged from 0 to 2.3N m,and the torque was small.Stepping motors with smaller torque could be selected to meet the low power requirement of the production measurement system.Maize plot breeding and yield measurement system consists of touch screen computer,inlet and outlet,weighing grain box,weight sensor,stepping motor,rotating barrel,grain collection box,mobile wheel,rotating silo baffle,shell and so on.The shell structure of key parts,weighing granary and rotating silo are calculated to ensure the accuracy of subsequent installation and test data.(2)Structural design of moisture measurement components,design of rotating barrel,two thin copper foils as measuring electrodes are embedded into the gap between the barrel body and the slot reserved for the central axis,which can realize the combination of capacitive moisture sensor and discharge barrel.Complete the capacitance measurement circuit;analyze the measuring principle of the weight sensor,use four sensors in parallel to complete the design of the weight measurement circuit;complete the design of the main control circuit,temperature measurement circuit,power supply circuit,motor circuit according to the work requirements of the production measurement system.(3)The software design of maize plot breeding yield measurement system consists of the overall system design,weighing subroutine,capacitance subroutine and system control software interface.C language programming is used to realize the reception and analog-to-digital conversion of temperature measurement circuit,weighing measurement circuit,capacitance measurement circuit and motor measurement circuit.The results are communicated to touch screen computer through RS232 serial port for data display,storage and printing.(4)The validation test was conducted to analyze the relationship between water content and temperature and capacitance of maize grains at 16.4,22.1,22.4 and 26.0 C.The fitting equation between water content and capacitance and temperature was established.R2=0.9704,which had strong correlation.Compared with the results measured by standard drying method,the error of the regression equation is smaller,which meets the requirement of high accuracy for water content measurement of production measuring equipment.The maximum error between the test value and the actual reference value is 0.17%.The sample moisture test circuit of capacitive moisture sensor is carried out,and the maximum error between the test value and the true moisture value of the sample is 1.37%.The measurement error is small,which shows that the design of the detection circuit is reasonable and meets the requirement of high precision measurement of the production measurement system.。The design of the plot yield measurement system will achieve rapid and accurate measurement of Maize Yield in the plot.