Key Technologies Research Of Automatic Seedling Offering Machine

Facilities horticulture technology is one of modern agricultural production mode to raise plants efficiently. Industrialized vegetable production is the advanced mode of facility horticulture. With the development of industrialized seedling production, automatic vegetable grafting machine plays an important role of replacing manual labor and improving the work efficiency. Most of existing cucurbitaceous grafting machines can realize the automatic grafting process, while the seedling feeding process still needs to be done manually. So it becomes a problem needed to be solved urgently and is a key technology to realize full automatic grafting machine.The key technologies of seedling feeding device are to position seedlings for grafting precisely, to automatically grab seedling flexibly and adjust its direction softly. In this paper, cucurbitaceous root stock under natural light was taken as the research object. Seedling raising tray was used to cultivate seedlings. Pumpkin and cucumber’s seeds were sown at the same direction and position. Geometric and mechanical characteristics of grafted seedlings were studied. The automatic seedling feeding end-effector and its control system was designed and tested. The main research contents and conclusions are as follows:(1)Characteristic parameters of grafted seedlings were studied. Characteristic parameters of grafted seedlings are the theoretical basis to design the automatic seedling feeding end-effector. In this paper, characteristic parameters of cotyledon’s projected length, hypocotyl height and so on of rootstock(pumpkin seedling) and scion(cucumber seedling) were measured to provide a theoretical basis for the design of seedling feeding device.(2)The overall scheme of automatic seedling feeding system was determined. Firstly, the characteristics of the factory hole tray seedling was analyzed, the technical requirements of the seedling feeding was clear and the automatic seedling feeding process was determined according to the physical characteristics of grafted seedlings. Secondly, through the analysis of seedling feeding process, the system will consist of the following parts: the control box, seedling raising tray delivery device, lateral delivery device, mechanism to change the direction of seedlings, automatic seedling feeding end-effector and other components. The function and design parameters of each component were studied. Finally, delivery devices were processed and assembled.(3)The end-effector was designed and simulated. According to the geometric parameters and mechanical parameters of the cucurbitaceous root stock, the seedling fetching approach and direction adjustment method was get. Three-dimensional modeling and interference checking of the end-effector was finished using Pro/E software. Then the standard parts were selected and purchased, the non-standard parts were designed and manufactured and the end-effector was assembled.(4)Control system of the end-effector was designed and tested. According to the designed seedling feeding process, the system structure, hardware selection, pneumatic connection and the control software of the end-effector control system were finished. The end-effector was adjusted to improve the success rate. At last, the experimental verified that this end-effector could meet the desired design requirements.