Optimized Design And Experimental Research On Critical Components Of Integrated Transplanter With Picking And Planting For Cotton Bowl Seedling

As the main economic crop in China,30%-50%of the output of cotton comes from the best cultivation technology,among which the transplanting technology of cotton seedling in bowl is one of the effective ways to increase production.There are main advantages as:(1)Compared with direct seeding,it can save more than 50%seeds,reduce planting investment and increase yield by 10%-20%;(2)It can save land resources,facilitate automatic management and control of water and fertilizer use and reduce the generation of pests and diseases;(3)We can improve crop quality and further increase farmers'income by breeding strong seedlings.The mechanical transplanting technology of potted seedling was first applied to paddy crops.The main models are rice transplanter and rice potted seedling transplanter.The development of relevant technologies is becoming more and more mature.Compared with paddy field transplanting,the mechanized transplanting of rice seedling in dry field faces more stringent technical requirements,resulting in its development far behind paddy field models.Foreign research and development of fully automatic transplanting models of rice seedling in dry field started earlier and achieved remarkable results.In Europe,America and other countries,multiple sets of electro-hydraulic control devices are used in series to complete the actions of seedling picking,conveying,hole opening and planting.The whole machine is complex in structure and expensive in price.Japan's development of the top bowl transplanter requires a special hard bowl,which leads to its high comprehensive cost and fails to be popularized in China.The domestic research on the transplanting machine of potted seedlings started late,most of the transplanting machines in the market are semi-automatic,which need manual assistance to feed seedlings.The low efficiency of transplanting,high labor intensity and high operation cost become the bottleneck to restrict the large-scale promotion of the transplanting technology of potted seedlings in China.The society needs to develop the full-automatic transplanting machine with high efficiency and light simplification.The design of agricultural machinery needs to be guided by specific agronomic requirements.China's vast agricultural planting area has a large base and many kinds.The specific requirements of the same agronomy for different crops are different.We should abandon blind introduction of foreign models based on different agronomic design,and develop key components of different models for the same agronomy based on the national conditions,so as to meet the agronomic requirements to reduce unnecessary design difficulty while requiring.As the two core components of the full-automatic transplanter,the seedling conveying device and the seedling collecting and planting mechanism send the potted seedlings to the seedling collecting position accurately and orderly for the continuous seedling collecting of the seedling collecting and planting mechanism.The seedling collecting and planting mechanism completes the potted seedling transplanting through the actions of seedling collecting,conveying,hole opening and planting,and the cooperation effect of the two directly affects the operation performance of the transplanter,which is the key to realize the full-automatic potted seedling transplanting.Therefore,it is the only way to solve the bottleneck problem of bowl seedling transplanting in China to design and study the seedling delivery device and seedling collection and planting mechanism,which has great theoretical significance and practical value.In this paper,according to the transplanting requirements of potted seedlings in clip resistant dry field,a transplanting mechanism of potted seedlings(ZL201811064900.7)is proposed,which uses a set of rotation mechanism to drive the seedling fetching mechanism and t he duckbill planter to complete the actions of seedling fetching,sending,receiving and planting;At the same time,a kind of vertical seedling delivery mechanism of ratchet connecting rod transplanter is designed.Thedesignmethodof"mechanismanalysis-kinematics modeling-programming-optimization experiment analysis"is used to optimize the vertical seedling delivery mechanism,and the design of seedling delivery and installation is completed by applying the scheme of realizing gearbox proposed by the research group.The work done in this paper is as follows:(1)According to the requirements of Agronomy,cotton potted seedlings are cultivated with the help of plant factories.The characteristics of potted seedlings in each seedling stage are statistically analyzed,and the suitable seedling age and its characteristics are obtained.In this paper,the characteristics of cotton seedling tolerance to clipping were studied.The results showed that the average stalk pulling force of cotton seedling aged 35 days was 44.550N.Compressive strength7.213N.Combined with previous research conclusions,proved that cotton seedling in bowl adopting the plan of transplanting by clamping stem.(2)Based on the movement mechanism of the rotary transplanting mechanism and the requirements of the duckbill planter for vertical planting,the"8"shaped seedling picking,delivering and"?"shaped seedling were put forward The non-circular gear system controls the seedling picking mechanism,and the non-circular gear system controls the duckbill planter,both of which share the same gearbox to form a complex trajectory and posture respectively,so as to complete the action requirements of seedling picking,conveying,opening and planting required by the potted seedling transplanting.(3)Taking the rotation angle of the seedling collecting planetary frame and the planting planetary frame as the known variable(the transplanting mechanism rotates at a constant speed),the kinematic model of the transplanting mechanism of the integrated bowl seedling is established,and the analytical formulas of the trajectory and posture of the seedling collecting mechanism and the duckbill transplanter are obtained,which lays a theoretical foundation for the optimal design of the transplanting mechanism of the integrated bowl seedling.(4)According to the kinematic theoretical model of transplanting mechanism and the agronomic requirements of transplanting operation,16 design requirements are put forward and digitized,and the"software for optimum design of transplanting mechanism with integrated transplanting bowl seedling"is developed.Embed the above objective requirements into the software,and display the change process through the progress bar.The optimization process can realize human-computer interaction.Operators can adjust parameters by observing the feedback results of optimization objectives,greatly reducing the difficulty of optimization,and can quickly and accurately solve the trajectory and attitude of the transplanting me chanism.All the target values are adjustable,and users can modify them according to specific design requirements to adapt to different transplanting requirements.The software has been registered(Registration number:2018SR983784).(5)Through software optimization,a group of transplanting structural parameters of potted seedling were obtained,and the absolute movement track and absolute angle of the planter were analyzed.During the process of soil and soil excavation,the planter kept approximately perpendicular to the ridge surface line,meeting the requirements of transplanting perpendicularity.The three-dimensional model of the mechanism was established and its absolute track was verified by virtual simulation.(6)According to the working principle and agronomic requirements of the ratchet linkage type longitudinal seedling delivering mechanism,the kinematic model is established and the design requirements are digitized.The"optimization design software of the longitudinal seedling delivering mechanism"(Registration number:2018SR473452)is developed to obtain the mechanism parameter values and the ratchet structure parameter range.By using the combined test method of the second orthogonal rotation center,the height of the ratchet driving surface x₁,the height of the ratchet positioning surface x₂ and the rotation speed x₃ of the seedling taking mechanism are taken as The success rate y of seedling delivery was used as the evaluation index.The high-speed camera technology was used to mark the angle of seedling de livery,so as to determine the success rate of seedling delivery,the parameter optimization test was carried out,and the regression model of the success rate of seedling delivery was obtained:According to the optimization results of the longitudinal seedling delivery mechanism,the physical prototype was tested and verified:when x₁=2.3mm,x₂=3.5mm,x₃=100r/min,the success rate of seedling delivery was 99.17%,which verified the reliability of the regression model,and the results met the design requirements.(7)With the help of 3D printing technology,a physical prototype of the transplanting mechanism was developed,and the verification test of the trajectory and attitude of the transplanting mechanism was completed with the help of high-speed photography technology.Experiments show that the results of theoretical analysis,optimization software,virtual simulation and physical prototype are basically consistent,which verifies the correctness of the design.A test-bed system for transplanting mechanism of potted seedling was established.The test system consists of seedling box,seedling delivery device,transplanting mechanism and movable strip-shaped soil trough.The accuracy of the action was verified by using high-speed photography to mark the movement track of cotton seedling in the process of seedling throwing and grafting.The experiment of seedling taking and planting showed that the success rate of seedling taking was 94.32%,the qualified rate of planting was 96.67%,and the excellent rate of planting was63.48%.