Principle Analysis And Parameters Optimization Of A Seedling Pick-up Mechanism Of Planetary Gear Train With Non-circular And Fourier Gears

Transplanting vegetables can effectively make good use of planting land, take advantage of light and heat resources, and also provide an easy work of seedling management; its comprehensive benefit is obvious. Commonly transplanting work can be done by two ways in the past: man-made or mechanization. As the adjustment of industrial structure in rural areas and under the constant promotion of agricultural mechanization, transplanting with machinery replacing manual transplanting becomes necessary. So author in this paper analyzed similar machine both at home and abroad, and proposed a new kind of rotary pot seedling transplanting mechanism. By using computer-aided design, a optimization software of new mechanism was self-developed. Based on its interactive interface, a group of good parameters which can be used to design the new mechanism for picking up seedlings automatically were optimized. Researches in this paper were done by using multiple means including theory calculation, 3D modeling and virtual simulation to confirm the correctness of the design. It is of significant meaning and provides reference for further research in transplanting area.The main contents of this paper are as follows:1) The latest research status of picking seedling mechanism both domestic and foreign was analyzed. After comparing the strengths and weaknesses of many different types of these mechanisms and according to the working environment and design requirements, a scheme of rotary planetary gear train with non-circular gear transplanting was determined.2) A new method of establishing pitch curves of non-circular gear was presented. Based on the new curve built, center distance of the gear pair was resolved and its follower gear shape obtained. On the foundation of new method, a new mechanism,vegetable pot seedling planetary gear train transplanting with non-circular and fourier gears, was put up in this paper. Then the working principle was introduced and the kinematic model was established.3) On the basis of the mathematical kinematic model built, interactive optimization software of the seedling mechanism was developed. The dimensions of the mechanism core component were optimized and simulation animation was rendered. On the other side, the target parameters of the picking seedling mechanism needed can be exported. Through this software, the effects regularity of the key parameters of mechanism on the pick-seedling trajectory can be concluded, and then parameter optimization was completed.4) Analyzing the existing disadvantages of the seedling transplanting arm of the pot seedling pick-up mechanism, a new type of transplanting arm was redesigned. Core components inside the transplanting arm including cam mechanism and seedling clips were devised, which can ensure the mechanism quickly picking up the seedlings and pushing seedlings fast. Then the detail structures of the whole transplanting arm can be finished.5) 3D model assembly of mechanism was established on CREO 3.0 platform and virtual prototype test of the seedling pick-up mechanism was conducted by ADAMS 2013. By comparing the two working trajectories of specific point on the mechanism, one in ADAMS simulation analysis and the other in MATLAB theoretical calculation, verified the correctness of the results of the new seedling pick-up mechanism.