Design And Experimental Research On The Soybean Planter With Rotary Tillage And Ditching

Sowing is a key part of agricultural production,sowing quality affects the growth environment and yield of crops greatly in the late.Soybean as the fourth largest planting crops in our country,its planting area and yield declined year by year.Huang-huai-hai region is one of the second major producing areas of soybean in china,its main planting pattern is no till seeding after mechanical harvesting wheat.In recent years,the government strictly prohibited straw burning,due to the lack of suitable no-till precision planter,and the right time for sowing soybean is short in the "three summer" season,therefore,causing the poor quality of soybean planting in the region,the economic benefits is low,the enthusiasm of farmers planting soybeans decline.Aiming at the urgent need of actual production,this subject reference technology status of soybean seeding machine at home and abroad,and considering the combination of agricultural machinery and agronomy,designed a rotary ditching soybean planter in order to improve the economic benefit of farmers planting,which also have important significance for grain production safety of soybean in China.In this paper,the research contents and conclusions are as follow:1.Designed the overall structure of the machine,and determined the machine working width of 2.3m,sowing rows of 6 lines,and the line spacing is 40cm,sowing depth is 3～5cm,sowing seed spacing is 3～15cm,and the seed spacing is stepless adjustable.The planter is mainly composed of the three-point suspension mechanism,rotary ditching device and sowing unit,seeding rate control device and so on.Supporting more than 55kw tractor,machine can complete rotary tillage,ditching,seeding,soil covering,repression and other operations once into the ground.2.Determining the type or structure of each key component.The ditching device,profiling mechanism,and double disk opener of planter were analyzed in detail to obtain parameters of the components.According to the design parameters of the key components of planter,complete manufacture of the first round prototype.Then,a preliminary field experiment was carried out in order to test the performance of the prototype.3.3D modeling software Creo2.0 is used to draw three-dimensional model of all parts of the planter,and complete the whole assembly of virtual prototype with the various parts.Then,use Creo2.0 motion simulation capabilities to analyze movement process of profiling mechanism.The simulation results indicated that trajectory of the opener is close to the actual terrain.4.Vertical disc-spoon soybean precision metering mechanism was chosen as the core component of the planter.According to the test method of GB/T 6973-2005 "Testing methods of single seed drills(precision drills)",seeding performance of metering mechanism was assessed by the method of single factor comparative test,of which working speed was as main influencing factor.The experimental results indicated that qualified rate was 80.9%～89.4%,multiple rate was 3.3%～8.5%,missed rate was lower than 15%,variant coefficient was less than 25%,while working speed was 2-4km/h,theory seed spacing was 8.5～11.5cm.5.Designed the seeding rate control system based on STM32 MCU,using do motor to drive metering mechanism instead of the traditional wheel drive device.System can obtain the forward speed of tractor using Hall sensor,and calculate the required rotational speed of metering mechanism according to the corresponding mathematical model,and outputs a PWM control signal to change the DC motor speed which match the speed of tractor in real time.Therefore,this system can accurately control the seeding rate,and ensure the uniformity of seeding.