Design And Research On Chain Rail Planting Device Of Tomato Seedling Transplanter

Xinjiang is the third largest tomato industry base in the world.It is of great significance to develop local mechanized transplanting equipment for tomato seedlings.However,the research on the transplanter planting device in China started late,and there is a lack of relevant research on the tomato seedling film planting device.At the same time,the existing film planting device still has some shortcomings,such as too short zero speed time,low verticality,too long film tearing and poor hole forming effect,resulting in damage in the process of seedling transplanting and low survival rate of transplanting.Aiming at the problems existing in the existing planting device,in order to improve the planting effect,this thesis designs a chain rail tomato seedling planting device,and systematically studies the planting device according to the analysis of tomato seedling physical characteristics,the structural design of planting device,kinematic analysis,dynamic analysis and simulation,virtual prototype analysis and bench test.The main research contents include:(1)35d tomato plug seedlings were selected,and their physical characteristic parameters were measured.The parameters such as plant height,leaf crown width,plant quality,canopy height and substrate diameter were counted.Combined with the physical characteristic parameters of tomato plug seedlings,the structure and size of planter were designed.According to the agronomic requirements of tomato seedling transplanting,the overall scheme,working principle and working parameters of transplanter and chain rail planting device were determined,and the transmission form and transmission route of planting device were put forward.(2)According to the zero speed seedling throwing theory,the planting trajectory of the chain rail planting device is analyzed,the zero speed point is determined,the planting point is kinematically modeled,the goal of planting trajectory analysis is determined,the planting trajectory function is established,the GUI human-computer interaction interface is developed,and various parameters are analyzed.Among them,the forward speed is negatively correlated with the film tearing length,and the planting depth and inclination angle are positively correlated with the film tearing length,The radius of the bottom sprocket has little effect on the tear film length,so it should be eliminated.The orthogonal test method is used to optimize the speed,inclination angle and planting depth of the planting device.The corresponding speed,inclination angle and planting depth of the two groups of optimal parameters are 0.410 M / s,91.278 °and 6cm;0.418 m/s,105°,6.3cm.(3)Calibrate the planting soil parameters,establish the discrete element model according to the calibration parameters,and compare the stacking angle between the simulated particles and the actual soil particles.The maximum error is within 5%.Comparing the two groups of mechanism parameters,the stress of the planting device is analyzed during the process of the planter penetrating into the soil.When the speed,inclination angle and planting depth are 0.418 M / s,105 ° and 6.3cm,the transverse resistance is obviously small and its hole forming performance is good.It is analyzed that the parts with relatively concentrated stress in the process of penetration are connecting rod frame and hinged frame.The stress analysis and finite element analysis are carried out on them.Under the action of load F1 = 2258.3 n,F2 =1686.1 N and F rail = 402.3 n,the maximum deformation variable is 1.137e-5 mm and 8.319e-3 mm respectively,which verifies the rationality of their structure.(4)According to the Adams model analysis of the chain rail planting device,the planting trajectory and stress analysis are verified,which provides the basis for the later stage bench design.The test bench of the planting device is built,and the film breaking test and non film drilling test are designed to verify the correctness of the kinematic and dynamic model analysis of the planting device respectively,and the reasons for the difference with the theoretical value are analyzed.