Design And Experiments Of An Automatic Transplanter For Sweet Potato Naked Seedlings Based On Seedling Belts

At present,sweet potato is mainly grown in naked seedling transplanting in China,mainly relying on manual and semi-automatic transplanting machines for transplanting.In view of the low degree of mechanization of sweet potato transplanting in China,the high labor intensity caused by the need for continuous manual placement of seedlings during naked seedling transplanting,and the inability of the current flexible disc to meet the agronomic requirements of horizontal planting in the process of naked seedling transplanting,this paper combines the physical characteristics of sweet potato naked seedlings and planting agronomy to develop an automatic transplanter for naked seedlings of sweet potato based on seedling straps and conducts field trials.The main research elements are as follows.1.Research on the automatic seedling division and feeding technology for naked sweet potato seedlings was carried out.In order to achieve automatic and orderly feeding of naked sweet potato seedlings,the physical characteristics of sweet potatoes were studied by means of experimental methods,and a pretreatment seedling belt was designed to fix naked sweet potato seedlings in an orderly manner,and an automatic seedling feeding method based on the pretre atment seedling belt was proposed.Based on the combination of the pretreatment belt and motor drive,an automatic seedling feeding device was designed to automatically feed the naked seedlings of sweet potato.By analyzing the working process of the seedling feeding device,constructing a motor variable diameter motion model,analyzing the relationship between motor speed and plant distance,and determining the motor speed control strategy of the seedling feeding device to achieve fixed frequency seedling feeding.2.Research on precision planting technology for naked sweet potato seedlings.According to the research on the yield of sweet potato by different planting methods,a theoretical analysis of the movement process of naked sweet potato seedlings clamped by a flexible disc was carried out to realize the horizontal planting of naked sweet potato seedlings,a mathematical model of the bending movement of naked seedlings touching the ground was constructed,and research on horizontal planting method of sweet potato bare seedling class based on flexible discwas carried out..The theoretical bending direction of naked seedlings after touching the ground was found to be determined by the height of the center of rotation of the disc from the ground,the forward speed of the machine and the speed of the disc,and the roots of naked seedling s would first move forward for some distance after touching the ground and the phenomenon of forward seedling delivery occurred.Through bench tests and simulation tests based on EDEM software,the bending and feeding state of naked sweet potato seedlings at different speeds were analyzed.When the forward speed of the machine was 0.25 m/s and the rotation speed of the disc was 1.4 rad/s,the actual bending direction of the naked sweet potato seedlings reached 98%of the theoretical direction,and the distance of the naked seedling roots moving forward after touching the ground was less than 10 mm.3.Combined with the agronomic requirements of sweet potato planting,a prototype of automatic transplanting machine for naked sweet potato seedlings based on seedling belt was designed and tested,integrating double-motor control of seedling feeding and planting system,capable of completing a series of operation processes such as rototilling and starting monopoly,automatic seedling feeding,horizontal planting and soil mulching and suppression at one time.After several trials and parameter adjustments,the automatic seedling feeding and transplanting operation of naked sweet potato seedlings was achieved.The planting posture was 87.8%.