| In this paper,the existing rice seeding machines at home and abroad are studied,combined with the requirements of agronomic production,and the influencing factors of rice seeding production are analyzed.It is found that the rice is easy to fall down and the plants are uneven in density during water direct seeding.Aiming at this problem,a control system that measures the speed of the sensor and automatically adjusts the hole distance by the motor is designed,and a seed blowing device that controls the depth of the rice planting by the fan.And designed a kind of active seeding rice water direct seeding machine to meet the requirements of precision hole direct seeding of rice.Through theoretical analysis,design and development of key components,and fluid simulation analysis,bench test,field test to verify its feasibility,the main research contents of this article are as follows:(1)Research on physical and mechanical properties of rice sprouts.Three rice varieties(Yixiang 3724,Ganxiangyou 702,Chuanguyou 642)planted in Sichuan Province and yielding better yields were selected.Measure the triaxial dimensions,sliding friction angle,angle of repose,thousand-grain weight of rice seeds and buds.The physical characteristics of the three rice seeds and buds were compared and analyzed.(2)Combined with the agronomic requirements of direct seeding of rice,a seed blowing device that blows seeds into the soil through a fan and an active seeding system driven by a motor-driven seeding shaft are developed.The theory of seed injection,seed injection and soil entry process of seed blowing device is analyzed.Analyze the relationship between the blowing structure parameters and the working parameters,calculate the total pressure when working at the time of seeding is 8900 pa,and the acceleration distance of the pipeline is 40 cm.Select the centrifugal fan,the selected seeding device is a mechanical seeding device,the number of holes is 8,the suitable seeding shaft speed is 0 ～ 450 r / min,and the seeding number is 2 ～ 4.According to the seed meter,the matched drive motor is selected,the power of the motor is 380 w,and the transmission ratio of the motor and the seed shaft is calculated as i = 2.Subsequent experiments and model building laid the foundation.(3)Simulation analysis of the air flow field based on Fluent.Use UG 3D modeling and ANSYS simulation analysis.For the full factor test of the gas distribution pipeline,the diameter of the gas distribution pipeline is determined to be 40 mm,the distribution mode is c-type,the pressure loss for the whole process is 2234 pa,and the coefficient of variation of the wind speed at the outlet of the pipeline is 12%.A single-factor test was carried out on the seed blowing pipe,and the nozzle of the seed blowing pipe was determined to be20 mm,and the optimal pipe wind speed was 30 m / s,and the pressure loss during the whole process was 3100 pa.The optimization of the entire pipeline structure provides a basis for determining the parameters of the live broadcast machine.(4)Bench test.On the basis of completing the prototype construction,a single-factor bench test was conducted through jps-12,and it was concluded that the faster the wind speed,the lower the planting height,the smaller the soil compactness,the greater the blowing depth;the speed update time is less,and the planting speed is The more precise the hole distance;on this basis,a multi-factor optimization test was conducted to determine the seed blowing height was 15 mm,the pipe wind speed was 28.4m / s,and the speed update time was 0.2s.(5)Field experiment of rice direct seeding machine.On the basis of completing the development of the rice seeding machine,field trials were conducted.The pass rate of hole spacing was 90% to 97%,the coefficient of variation of hole spacing was 8.28% to 16.15%,the average sowing depth was 6mm to 11 mm,and the standard deviation was 1.3 mm ～2.1mm,the pass rate of sowing depth is 85% ～ 97%,and the coefficient of variation of sowing depth is 13.09% ～ 18.75%,which meets the requirements of rice direct seeding. |
