| The black soil region in Northeast China,as one of the world's three major black soil regions has high natural fertility and is suitable for agricultural production.So it is the most important grain production basein China.Traditional agricultural production is dominated by intensive cultivation mode.Agricultural machinery implements into operation for many times,and causes frequent disturbance on soil;farmland is in the bare leisure state for 7 months for per year,and suffer serious wind erosion and water erosion;excessive application of pesticide and fertilizer hardens soil.Therefore,to prevent the soil and water loss,and improve soil fertility in the Northeast China black soil region of great significance for ensuring national food security,improving the ecological environment,and realizing the sustainable development of agriculture.Conservation tillage technology can preserve soil moisture,reduce cost,increase efficiency,improve the organic matter content of soil,decrease soil wind erosion and water erosion.It has been promoted and applied throughout the world through years of research and development.The core link of conservation tillage technology is crop residues mulching and no-tillage planting operation,so the performance of precision metering device decides the effect of conservation tillage in no-tillage planting operation.Compared with ordinary planter,no-tillage planter has worse working environment.Surface roughness,straw and residues can make planter vibrate;vibration has more significant influence on precision metering device especially in the process of the high speed precision seeding.Therefore,the influence law of vibration on metering device performance under conditions of straw mulching was emphatically studied,and then the corresponding vibration attenuation workparts were designed toreduce vibration on no-tillage planter and improve the quality of seeding.(1)First of all,the impact of planter vibration on the quality of seed-metering device was explored through the contrast test;the vibration features including vibration acceleration,frequency and amplitude in the process of seeding monomer work were obtained through the method of the soil-bin testing;a vibration tablewas designed,which could simulate the operating condition of field operating and test the operating performance of seed-metering device when vibration was applied.(2)A kind of automatic control method of no-tillage planter seeding monomer vibration attenuation was proposed.The automatic control system and corresponding software seeding monomer vibration attenuation were designed.Depth control tire surface deformation sensor was made through PVDF piezoelectric film.The pressure seeding monomer on ground was real-time monitored.The actual furrowing depth was calculated.When there was a deviation with expected depth,the system could increase the pressure of seeding monomer on ground by controlling the air spring,reduce seeding monomer vibration,and improve the quality of seeding.According to the field test results,when the automatic control system of planter seeding monomer operatedat the speed of 5~8 km/h,the qualified rate of seeding depth was above 91%;vibration acceleration was decreased by more than 30%;vibration frequency was reduced by more than 24%;amplitude was reduced by more than 30%.The automatic control system of seeding monomer had superior performance over passive copying device in the process of high-speed operation.(3)A kind of no-tillage planter straw cutting anti-blocking mechanism was designed.Composite blade structurewas adopted.Cutting partingtools were installed in three planes of each anti-blocking device.To be specific,the cutting partingtools on both sides adopted passive rotation operation,and the cutting partingtool at the middle adopted passive rotation operation;supporting cutting operation could be conducted on the straw(stubble)during the operation so it could increase cutting rate,and lower power consumption.Experimental results were as follows: the descending significance order of the influencing factors on the cutting rate of straw(stubble)was active cutter-head rotation speed,blade radius of gyration,and forward speed of seeder;the descending significance order of the influencing factors on the single blade power consumption was active cutter head rotation speed,forward speed of seeder,and blade radius of gyration.Under the premise the root crop cutting rate was guaranteed above 95%,the best combination of straw(stubble)cutting rate and single blade power consumption was predicted through software Design–Expert,namely,2.1 m/s offorward speed of seeder,120 r/min of active cutter head rotation speed and 200 mm of blade radius of gyration.Validation test was conduced according to the optimal parameters.The results were as follows: the maximum,minimum and average value of straw(stubble)cutting rate obtained through best work parameter combination was 94.9%,94.9% and 95.3%;the maximum,minimum and average value of power consumption of single blade were 147.5 W,144.4 W and 145.2 W.(4)A kind of no-tillage planter seeding monitoring system was developed,including seeding monitoring subsystem,sowing seed detection subsystem,GPS subsystem and remote serve.GPS receiver was regarded as miss-seeding andre-seeding position collector;GPRS DTU module was regarded as remote transmission tool;STM32 MCU was regarded as the core processor;PVDF piezoelectric sensor was regarded monitoring component.The system could accurately real-time monitor the technical specifications of the seeder,and realize data reception,storage,query,statistics,analysis,processing and alarm functions for there mote transmission and remote server program of sowing quality information data.The field test results showed that the remote seeding monitoring system had stable and reliable performance,was able to effectively monitor seeder sowing quality;its seeding rate detection accuracy was 97.4%;miss-seeding detection accuracy was 96.1%;re-seeding detection accuracy was 95.9%.Thus,the system showed higher re-seeding detection accuracy,and realized accurate positioning of sowing quality information position.(5)The design of 2BMZ-4 wide/narrow row no-tillage planter was improved and complete machine field experiment was conducted.The practical operation effect of no-tillage planter monomer vibration automatic control system,straw cutting anti-blocking device and remote monitoring system was investigated.The test results showed that each work index of the improved 2BMZ-4 wide/narrow row no-tillage planter was higher than the national standard requirements.The above work provided technical reference for the research on key technology of corn no-tillage planter precision sowing,and had practical application value. |
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