| Aiming at the low degree of automation of the existing semi-automatic grafting equipment for cucurbitaceae seedlings,this paper studies the automatic jointing device of cucurbitaceae top-plugging method.In this paper,according to the agronomic requirements of the top insertion method,a terminal mechanism that can complete various joint actions is designed.Based on computer vision technology,the non-contact grafting parameter identification of grafted seedlings is realized,and various actions of the joint mechanism are realized according to the identification results.visual servo control.The innovation of this paper is: a method of identifying and positioning grafting parameters based on computer vision,to achieve high-precision identification and positioning of the growth point of grafted seedlings,the width of seedling stems and the direction of rotation of cotyledons,and design a multi-functional rotary grafting terminal.Reduced device size.The research work of this paper mainly includes the following aspects:(1)Research on the visual recognition method of the grafted seedlings of Cucurbitaceae.In order to quickly and accurately identify the main grafting parameters such as the growth point,seedling stem width,and cotyledon rotation direction of the grafted seedlings of Cucurbitaceae,this paper firstly constructed an image acquisition system that can obtain the top-view and side-view images of the grafted seedlings.The mainstream image processing technology based on convolutional neural network is not dominant in terms of speed and accuracy under the conditions described in this paper.Therefore,this paper adopts an ordered contour chain extraction method based on target pixels.As a result,the tangent angle is extracted from the top-view image,and the single-pixel skeleton is extracted from the side-view image.Finally,according to these two results,the growth point of the grafted seedling,the width of the seedling stem and the rotation direction of the cotyledon are recognized respectively.The results show that the maximum error of the growing point location of the top-view image is 3 pixels,the average error is 0.3 pixels,the maximum error of the cotyledon rotation angle is 8°,and the average error is 4.35°.The average error of the measurement of the seedling stem width in the side view image is 0.11 mm,and the maximum error is 0.2mm.(2)Research on the design of the top insertion method combined device.With reference to the agronomic process of the top plugging method,a corresponding device was designed for the four steps of secondary cutting of the scion seedling,removing the rootstock seedling to the normal point,inserting the grafting hole,combining the scion seedling with the rootstock seedling,and combining the latter three devices.Become a multifunctional grafting rotary terminal.In order to make the above multi-terminals cooperate with each other,a terminal carrier drive device is designed,and a rotating joint that can provide sufficient torque is designed to control the operation of the multi-functional rotating terminal.The mechanical analysis results show that the joint can provide a maximum force of 727 N at the terminal.,which meets the requirements of the device during operation.Finally,the kinematic analysis of the device was carried out.(3)The control and experiment of the top-plug method combined device.A corresponding control system is constructed for the top-plug method combination device designed in the second part.On this basis,the growing point positioning results obtained in the first part are converted into actual coordinates.Through experiments,the positioning errors in three directions are found.All are less than 1mm,and the average error is 0.46 mm.Subsequently,the control parameter extraction and precision experiments were carried out on the top-plug method combined device.The experimental results showed that the average error of the two moving joints of the device was 0.02 mm,and the maximum error was 0.05 mm.The average errors of the two rotating joints of the device were 0.002° and 0.02°,respectively,and the maximum errors were 0.003° and 0.03°,respectively.Finally,in the case of actual grafting,the position and depth of the grafting hole are used as the judgment basis,and the motion control precision experiment is carried out on the top insertion method.0.8mm and0.3mm,the average errors are 0.414 mm and 0.141 mm respectively,the maximum error between the actual length of the grafting hole depth and the expected distance is0.77 mm,and the average error is 0.227 mm. |
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