Study On The Monitoring Method And Device For Cleaning Loss Of The Rapeseed Combine Harvester

The overall level of Rape Mechanization in China,especially the level of harvesting mechanization,is seriously insufficient,the mechanization rate of rapeseed harvest was only 29.4%.One of the important reasons is that rapeseed harvesting loss are large,and the loss of cleaning is about 40%-60% of the total loss.A kind of multi block cleaning loss monitor was put forward in the rear of the rapeseed combine harvester.The loss seed was counted by the principle of piezoelectricity,and the loss seed was counted by the principle of piezoelectricity.According to the mathematical model between the monitoring amount and the amount of cleaning loss,the monitoring scheme of the cleaning loss is obtained in real time.The details of the work are as follows:(1)Establishing a monitoring model for the loss of cleaningThe distribution of the lost rapeseed at the different fan speeds was obtained,and the loss monitoring model was established.the transverse and longitudinal distribution of the rape seeds were obtained at the different speed of the fan,and the transverse cleaning loss model and the longitudinal cleaning loss model were established,so the loss monitoring model was induced.According to the variance analysis of each row loss,the location of the sensor is preferred.In addition,the physical properties of the main components of the ejecta were measured,which lay the data foundation for the simulation of EDEM.(2)Design of multi block cleaning loss monitoring deviceThe difference between the response of rapeseed,short stalks,shells and monitoring boards in cleaning ejecta is an important characteristic for distinguishing each component.the model of rapeseed,stem and shell was established in the discrete element software EDEM,and the collision process between the components and the monitoring board was simulated.The results showed that the frequency of the rapeseed collision monitoring board caused the vibration frequency in 14-20 KHz,the stem and the corner fruit shell were less than 2KHz,providing reference for the range of the cut-off frequency of the signal processing circuit filter.A set of multi block cleaning loss monitoring device is designed.It is mainly composed of four monitoring boards with P5-3B piezoelectric,and the piezoelectric ceramics are connected with the processing circuit through signal wires.The processing circuit mainly includes charge amplification,bandpass filter,full wave rectification and voltage comparison.Through this processing circuit,it can identify the selected loss of rape seeds from the interference of stem,shell and grasses and so on to get rid of the cleaning loss.(3)The vibration and vibration isolation design of the sensorBasing on the vibration signal measured by the DH5902 vibration tester,on the one hand,the vibration caused by the unbalanced force of the reciprocating vibrating screen is reduced.On the other hand,the vibration isolation structure is designed to weaken the influence of vibration transmission on the sensor.In order to test the performance of the loss sensor,different quantities of grain flow,stem,shell and material mixture were tested on the test bench for the demarcation of the cleaning loss.Field test was carried out on the TH988 rapeseed combine harvester.The results showed that the overall performance of the monitoring device was good and the accuracy rate of monitoring was above 90%.