Key Technologies Of Automatic Seedling Feeding System For Cucurbitaceous Grafting Machine

Facilities horticulture technology is one of modern agricultural production mode to raiseplants efficiently. Industrialized vegetable production is the advanced mode of facilityhorticulture. With the development of industrialized seedling production, automatic vegetablegrafting machine plays an important role of replacing manual labor and improving the workefficiency. Most of existing cucurbitaceous grafting machines can realize the automaticgrafting process, while the seedling feeding process still needs to be done manually. So itbecomes a problem needed to be solved urgently and is a key technology to realize fullautomatic grafting machine.The key technologies of seedling feeding device are to recognize the parameters ofseedlings for grafting automatically and to grab seedling and adjust its direction softly byseedling feeding end-effector. In this paper, cucurbitaceous root stock under natural light wastaken as the research object. The Image recognition method of root stock characteristicparameters for seedling feeding is studied. The automatic seedling feeding end-effector and itscontrol system was designed and tested. The main research contents and conclusions are asfollows:(1) The overall scheme of automatic seedling feeding system was determined. Firstly, thecharacteristics of the factory hole tray seedling was analyzed, the technical requirements ofthe seedling feeding was clear and the automatic seedling feeding process was determined.Secondly, through the analysis of seedling feeding process, the system will consist of thefollowing5parts: hole tray conveying device, seedling detection device, automatic seedlingfeeding end-effector, mechanical arm and the control system. The function and designparameters of each component were studied. Finally, the automatic device for root stockfeeding was processed and assembled(2) Cucurbitaceous root stock parameters for seedling feeding were studied. The growthcharacteristics of the hole tray seedlings was analyzed and the image acquisition system andmethod was get by comparison experiment. Different color component and their combinationoperation of commonly used color space were compared and a*channel component of L*a*b*color space was choose for subsequent image processing. Otsu method was used for thresholdsegmentation, morphological operation and area threshold was employed to remove residualnoise. Target seedling parameters were recognized by the Minimum circumscribed rectangle method and Hough ellipse fitting method respectively. Different applications of these twomethods were determined.(3) Hardware of the end-effector was designed. According to the geometric parametersand mechanical parameters of the cucurbitaceous root stock, the seedling fetching approachand direction adjustment method was get. Three-dimensional modeling and interferencechecking of the end-effector was finished using Pro/E software. Then the standard parts wereselected and purchased, the non-standard parts were designed and manufactured and theend-effector was assembled.(4) Control system of the end-effector was designed and tested. According to thedesigned seedling feeding process, the system structure, hardware selection, pneumaticconnection and the control software of the end-effector control system were finished. At last,the experimental verified that this end-effector could meet the desired design requirements.