| The advantages of transplanting and planting in the planting industry have made the important component of the transplanting institution,the seedling pick-up mechanism,a hot spot in the research of modern agricultural machinery.The existing types of transplanting mechanisms are lacking,and the planetary wheel train picking mechanism can realize high-speed movement,but there are fewer design methods in which precise posture can be realized;the rod mechanism with simple transmission form can achieve precise posture requirements,but if you want to achieve complex motion,the design is difficult,and during the seedling operation,the efficiency is not as good as the planetary gear train mechanism.Therefore,in order to develop a high-efficiency seedling pick-up mechanism that can achieve the ideal working trajectory,the thesis envisages the calculation of the size and center of rotation of the rod based on the given objective trajectory and key position requirements of the key points.Then,the rod mechanism is combined with the theoretical design of the wheel train mechanism to develop a wheel train mechanism that can achieve precise position and posture.The main research contents of this paper are as followed:1)Analysis of the status quo of seedling pick-up mechanism at home and abroad,although research on the seedling pick-up mechanism has made some progress,but due to its structural limitations,the seedling effect is not in line with expectations.By comparing the design method and transmission structure of the existing planetary gear trains,this paper starts from the better seed trajectory and the precise position and posture requirements that need to be met,and determines the trajectory and attitude of the needle tip point.Four precise position and posture points and one fuzzy position and posture point are used to establish the Burmeste curve,and the mechanism size constraint is used to finally obtain a feasible solution.2)A new non-circular gear planetary gear train seedling pick-up mechanism is proposed,and its mechanism composition and working principle are analyzed,and its kinematics model is established.3)For the transplanting of vegetables,the demand for each position and angle was adjusted,and the kinematics goal of the seedling pick-up mechanism was determined.Based on the GUI module in MATLAB software,the comprehensive design software of the seedling pick-up mechanism is compiled.Through the design software,the data results and data graphs can be presented,and the visual output of the results is realized.4)AutoCAD is used to complete the structural design of the seedling pich-up mechanism,and Solidworks software is used to complete the 3D modeling and virtual assembly of all components.Finally,using Adams software for motion simulation analysis,the attitude angle of the seedling arm is obtained when the simulated seeding trajectory and the five key positions of the seedling pick-up mechanism are set.It is verified that the results obtained after the simulation are highly consistent with the theoretical results,thus verifying that the seedling pick-up mechanism designed by this method is correct and feasible.5)The processing of the prototype of the seedling pick-up mechanism was completed.The actual seeding trajectory was obtained by the idling test,and the trajectory was highly similar to the theoretical trajectory.When the tool is used to obtain the five key positions that have been set,the azimuths of the seedling arms are 169.3,140.4,121.8,125.7,74.9,the error is very small compared to the theoretical azimuth,within the tolerance of its error.After the seedling pick-up experiment of different speeds,when the highest speed is 60r/min,the success rate of seedling collection can reach 92%.The test results can prove that the seedling pick-up mechanism designed in this paper has high reliability. |
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