| At present,the domestic vegetable planting is still dominated by the field.The domestic vegetable plug seedling automatic transplanting machinery is mostly a walk-behind,self-propelled transplanting machine used in the greenhouse greenhouse transplanting operation,which cannot meet the increasingly urgent needs of field vegetable automatic planting.However,most of the hanging transplanting machines for field operations in the field are mainly semi-automatic operation methods that require low operating efficiency and require manual seeding,and have a single function.Therefore,a hanging automatic transplanting machine was developed to plant high-quality vegetables.And saving labor is very important.In order to solve the problems of low efficiency and single function of the existing field transplanting models,a hanging automatic vegetable transplanter with functions of automatic seedling taking,seedling throwing,planting,watering and plug tray recovery was designed.Combined with the current research results of the hanging transplanting machine,a hanging chassis bracket and a high-speed pneumatic seedling harvesting mechanism that meet the needs of the operation of the automatic transplanting machine were designed.The theoretical design,simulation and test analysis of the key components and the whole machine were carried out.The main research contents are as follows:(1)The development status of vegetable transplanting machinery at home and abroad was studied and analyzed,and the main type of transplanting machine was determined to be hanging.The overall design scheme and overall machine design parameters of the hanging automatic transplanter were formulated,and the structural composition and working principle of each mechanism were described.The design and calculation of the transplanting system of the transplanter was carried out.(2)In order to meet the requirements of high-speed fixed-point fetching and seeding,a highspeed reciprocating seedling-fetching mechanism based on a portal frame structure is designed.Based on the analysis of the dynamic characteristics of the pneumatic seedling harvesting mechanism,it is determined that the key component that affects the accuracy of the seedling throwing is the longitudinal linear cylinder,and the factors that affect the movement characteristics of the pneumatic components are determined.The cylinder motion model is established;with the goal of lightweighting the structure,the Topological optimization of the cylinder connection device and installation backplate of the seedling harvesting mechanism,the optimized component quality was reduced by 12% and 4.2% respectively;the electromagnetic valve simulation model,safety valve model and longitudinal direction in the pneumatic component of seedling harvesting were built by AMESim The linear cylinder simulation model uses the Box-Behnken response surface design optimization method,optimizes the range of pneumatic parameters through constraints,and optimizes the optimal parameters for cylinder operation.AMESim aerodynamic simulation and ANSYS response spectrum simulation analysis are performed.The maximum displacement is reduced from 28.109 mm to 4.309 mm,which proves that the light weight of the structure and the optimization of aerodynamic parameters have a positive effect on the success rate of the seedling feeding mechanism.(3)Carry out the design of the chassis support of the hanging transplanter,and determine and analyze the stress state of the chassis support under two working conditions: the unlifted state of the planting operation and the lifted chassis support of the machine.The key working condition of the chassis bracket is determined as the lifting working condition,and the strength and rigidity of the key load beam under the lifting working condition are checked.Using ANSYS to carry out static and modal analysis on the chassis bracket of the transplanter under the unlifted working condition,it is concluded that the overall stress deformation of the fuselage is properly controlled when the crane is not raised in the static or traction working state;when the chassis bracket is in the raised working condition,pass Static analysis found that the fuselage showed large deformation and stress values close to the strain limit of the material;the chassis bracket was structurally optimized,and the optimized chassis bracket structure stress distribution tended to be reasonable,the deformation amount was reduced by 30% and the stress was reduced by 33.29%,Laid the foundation for the stable operation of the transplanter.(4)The 72-hole tray seedling seedling-raising mechanism bench test and the prototype performance test of the prototype were conducted at 60 plant / row / min and 72 plant / row / min.Statistics of average seedling leakage rate,injury seedling rate,and successful planting rate under different planting frequencies.Under the two planting frequencies,the average success rate of taking seedlings and throwing seedlings was 96.3% and 93.4%.The prototype was tested for overall performance.Under two planting frequencies,the average pass rate for transplanting was 96.5% and 94.2%.Tests show that the components of the automatic transplanter are in coordinated operation,and the overall planting performance is stable,which basically meets the performance target of the expected design of the transplanter. |
