Design And Study On A Pre-cutting Cassava Planter

Cassava(Manihot esculenta Crantz)possesses characteristics of fast growth and high yield.It can be used in the starch industry and pharmaceutical industry as well as the ethanol and biofuel production industry.Our country has a huge demand for cassava and cassava products,and every year we need to import a large amount of dried cassava and cassava starch from abroad.At present,the cultivation of cassava in our country requires a huge amount of labor with intensive work.Besides,there are overlaps among planting periods of cassava and other plants like sugarcane which results in further labor shortage and higher planting costs.Therefore,how to reduce the planting cost of cassava has become a prominent problem encountered by the cassava industry.Compared with traditional artificial planting,the real-time seed cutting cassava planter and pre-cut seed artificial planter promoted and applied in the current market have much higher efficiency.However,each planter requires the cooperation of multiple workforces and the process also involves heavy labor.Thus,it is of great significance to design and research a precut cassava planter to solve the problems of high planting cost and high labor intensity for promoting the development of the biofuel ethanol industry and improving the degree of agricultural mechanization.The cassava planter designed in this paper is mainly composed of a separation mechanism,arrangement mechanism,and planting mechanism.The separation mechanism continuously separates a small number of cassava seed-stems from the water tank with the help of the buoyancy force of water,and the number of seed-stem entering the arrangement mechanism was controlled at each time.Then the arrangement mechanism dispersed a small number of cassava seed-stems through the conveyor belt and sponge roller,and the dispersed seed-stem is arranged in an orderly manner under the action of the inclined groove.Finally,the planting mechanism can quickly and effectively take out and plant the seed-stem stored in the seed tubes one by one to achieve automatic planting.The main research contents are as follows:(1)Design the overall scheme of the cassava planting machine with plans on the separation mechanism,arrangement mechanism,and planting mechanism.The threedimensional model of the cassava planting machine is established by Solidworks.The key parts are simulated and analyzed by Abaqus software.We combine Abaqus and Isight software to simulate and optimize the separation plate and the driven axle.After optimization,the maximum displacement of the separation plate after optimization decreased by 32.94% compared with the previous optimization.The maximum stress decreased by 37.43% than before.The maximum displacement of the drive axle after optimization is 0.234 mm,which is less than the allowable displacement.The hardware circuit and software design of the control system are both completed on paper.As for the hardware circuit,it is mainly composed of a motor drive circuit,sprocket speed feedback circuit,walking speed detection circuit,and conveyor belt blockage detection circuit.As for software design,it includes the main program,separation system control subroutine,arrangement system control subroutine,and planting system control subroutine.(2)By the orthogonal test of cassava seed-stem falling is also carried out,index to explore the movement rule of falling cassava seed-stem on the connecting plate.Taking the parallelism rate of seed and stem as the test,the test results show that when the falling height is 50 mm with 60° of inclination,200 mm of the plate width and medium plate surface smoothness,the seed-stem parallelism is at its best performance.Based on the analysis of the seed stem falling test results,the connection plate structure design in the separation mechanism is determined.The cassava seed-stem dispersion test was carried out with the dispersion rate as the test index to explore the dispersion rule of stacked cassava seed-stem on the conveyor belt.The test results show that the dispersion rate is at the best when the conveyer belt moving speed was 0.22m/s with a 30° installation angle and 3 sponge rollers.Taking the cassava seed-stem No.5 in South China as the test object with the chain speed,brush speed,distance between the water surface and top of the box,and brush stop time as the test factors,plus the seed-stem separate efficiency and average seed number as the test indexes for seed-stem separate,we carried out a segregated experiment.The results show that the distance between the water surface and the top of the box has the greatest influence on the efficiency and the average seed-stem number,The best combination of seed-stem separation efficiency and average seed-stem number is when the chain speed is 0.14m/s,with 30r/min the brush speed,3cm for the distance between the water surface and the top of the box is,and 2s of brush stop time.The main working parameters of the separation mechanism are determined through the analysis of the seed-stem separation test results.(3)The prototype performance test shows that when the tractor walking speed is1.575km/h,the planting efficiency of the planter can reach 0.625roots/s while the average planting accuracy of the two rows is 81%,the average sowing omission rate of the two rows is 12%,the average repeat seeding rate of the two rows is 14%.It can achieve double row interlaced planting and meet the planting requirements for planting mode of width and narrow double row ridging,which indicates that the working principle of pre-cut seed cassava planter designed in this paper is reasonable and feasible.