Design And Experiment Of Watermelon Seedling Clip-Guard Transplanting Mechanism

Watermelon is widely planted in China,with an area of about 2 million hm~2.At present,the domestic watermelon planting relies on artificial planting or semi-automatic planting with the high labor intensity and the low efficiency,it is difficult to large-scale planting in a short time.Watermelon seedlings have thin stalks,large root crowns and irregular seedling shapes,in addition to the field’s harsh working environment,the automatic transplanting mechanism damages the stem and cotyledon of watermelon seedlings in the transplanting process,it will affect the lat er growth and yield.Reducing the damage to seedlings caused by the automatic transplanting mechanism in the process of watermelon planting has become a key issue in the development of automatic transplanting mechanism for watermelon seedling.To solve the above problems,this paper improved the extensible seedling-picking transplanting mechanism.The new clip-guard watermelon seedlings transplanting mechanism was designed which composed by the seedling protection device and the seedling-picking device.It can complete a series action of transplanting,such as seedling picking,protecting seedling,transporting and planting,The mechanism can protect the stem of seedlings while picking the seedling pot,reducing the damage of seedlings,ensuring the relative position between seedlings and the end-effector,improving the planting quality.It provides the reference for the automatic transplanting machine of watermelon.The main conclusions of this paper can be listed as follows:(1)A new end-effector was designed for seedling-picking and seedling-protecting at the same time.The combination of the end-effector and the non-circular gear was used to transplanting the potted watermelon seedlings in a better way that the end-effector can completer the seedling-picking and seedling-protecting in simultaneously.And the mechanism can avoid the damage of stem and crown cotyledons of seedlings It also can ensure the relative position of seedlings and end-effector,the integrity of soil pot and improve the quality of planting.the structure of the transplanting mechanism was simple and reliable.(2)According to the morphology of watermelon seedlings and the agronomic requirements of watermelon transplanting,simulating the posture of artificial transplanting seedlings,the relevant requirements of watermelon implanting were came up.The theoretical model of Clip-guard transplanting mechanism was established by analyzing the working principle of transplanting mechanism.(3)The agronomic requirements and seedling morphology of watermelon transplanting were transformed into the digital optimization goal.With the help of the research group’s optimization design platform,theoretical model and digital optimization goal,the optimization software of watermelon seedling transplanting mechanism was developed.the structural parameters meeting the requirements of potted watermelon seedlings transplanting were obtained by the help of the optimization software.(4)To get the ultimately size of the transplanting mechanism by the analyze of planting track,protecting track and the swing angle of taking-bowl piece in the taking bowl.The structure of rack-rack and seedling pusher is designed to ensure the synchronism of taking bowl and protecting seedling.(5)According to the optimized structural parameters after verification,the 3D virtual prototype assembly and inspection of the transplanting mechanism were carried out by Solid Works 2014.The virtual prototype which have been checked for reasonable was imported into Adams 2014 for virtual motion simulation,and the relevant data obtained from the virtual simulation was compared with the theoretical data,and the two dates were basically consistent,which verifies the correctness of the theoretical model and the structure design of virtual prototype.(6)Assembling the parts which processed by the 3D printing technology.The working track of the physical prototype was obtained by means of high-speed photography and video tracking technology.Comparing and analyzing the theoretical track and the working track to further verify the rationality and correctness of the transplanting mechanism.(7)The potted watermelon seedling transplanting mechanism was installed on the experimental platform.A performance comparison test was carried out between the conventional transplanting mechanism which without seedling protection device and the clip-guard transplanting mechanism.First the results of the comparative test showed that the success rate of clip-protected transplanting mechanism was increased by 5%,the success rate of planting increased by 7.5%,the qualified planting rate increased by 7.5%,the excellent rate of planting increased by 15%.Second,the results of comparative tests show that the clip-guard transplanting mechanism can obviously improve the planting quality compared with the conventional transplanting mechanism.Third,the comparative test results further verified the advantages of potted watermelon seedling transplantation mechanism.