Melon Robotic Grafting: A Study on the Precision Cutting Mechanism and Experimental Validation

Abstract

The grafting machine cutting step is the core step of the grafting process. The existing grafting machine cutting mechanism adopts fixed angle cutting and manually adjusts the cutting angle based on experience, and the cutting angle is not definite for rootstock cutting in different growth periods. In this paper, we proposed a method to guide the precise cutting mechanism according to internal and external parameters of melon rootstock at a specific period. First, we constructed a cutting model based on internal and external characteristics of rootstock cutting in the growth period of “two leaves and one core” and clarified the safe cutting area. Second, we designed a rotary precision cutting mechanism for rootstock cutting with automatic angle adjustment and constructed the displacement equation of the cutting trajectory of the cutter according to the cutting model. Last, we examined the cutting effect of the precision cutting mechanism and determined the precise cutting angle of the rootstock cutting mechanism in the growth period. Finally, the cutting effect of the precision cutting mechanism was examined, and the precision cutting angle of the rootstock during the growth period was determined. A comparison test between the precision cutting mechanism and the traditional cutting mechanism was carried out, and visual images of the incision were captured and analyzed. The results show that under the five horizontal cutting angles in the safe cutting area of rootstock, the length of the cut surface is inversely proportional to the cutting angle, and the flatness of the cut surface is directly proportional to the cutting angle. Comprehensive evaluation of the length of the cut surface, the cutting success rate, and the quality of cutting revealed that the average cutting angle of the precision cutting mechanism in the safe cutting area (26°) is better than that of the traditional cutting mechanism. It meets the technical requirements of the cutting technology for mechanically grafted rootstocks. The results provide a reference for studying new rootstock precision cutting mechanisms and cutting angle adaptive control models.

An Original UV Adhesive Watermelon Grafting Method, the Grafting Device, and Experimental Verification

“…1 ⃝ The spray valve (2) and UV curing lamp (13) in the vertical direction are fixed and mounted onto fixture (1), with fixture (1) through the column mounted onto frame (8); 2 ⃝ The rootstock adsorption mechanism (4), rotary cylinder (6), and X-axis linear slide (12) are installed on the sliding plate (7). The sliding plate ( 7) is installed on the frame (8) using a linear slide block; 3 ⃝ The scion adsorption mechanism (11) is mounted onto the X-axis linear slide (12), and the X-axis linear slide (12) drives the scion adsorption mechanism (11) to complete the incision butt joint movement for the rootstock seedling; 4 ⃝ The rootstock adsorption mechanism (4), the rotary cylinder (6), and the scion adsorption mechanism (11) are arranged from left to right, and the centers of the adsorption grooves of the rootstock adsorption mechanism (4) and the scion adsorption mechanism (11) are coaxial, which facilitates the realization of accurate butt joining of the scion seedling incision; 5 ⃝ The scion positioning plate ( 5) is mounted onto the rotary cylinder (6), used for the scion on the seedling limit; 6 ⃝ The Y-axis linear slide ( 9) is also installed on frame (8); the Y-axis linear slide (9) and sliding plate (7) are connected and fixed, for the rootstock and scion, and transported to the spray valve (2) and UV curing lamp (13) below, respectively, for glue spraying and curing operations.…”

“…The selection of disease-resistant rootstocks can significantly reduce or avoid yellow wilt, wilt, root rot, green blight, and root-knot nematodes and other soil-borne pests and diseases in vegetable crops, can effectively overcome the barriers to continuous cultivation, and can increase the number of planting stubble in the same plot of land to improve the land utilization rate. At present, watermelon seedlings are grafted artificially [9][10][11], fewer people work in grafting as China's rural population ages [12], and the quality and efficiency of manual grafting can no longer meet the production requirements of factory nurseries. Mechanical grafting has the advantages of standardization, high quality, and high efficiency [13,14], which is the development direction for factory-grafting seedlings [15].…”