Simulation and experimental study of flexible adsorption and localization mechanism for vegetable grafting machines

Because of the lack of good seedling positioning during vegetable grafting, there are issues such as high labor costs and long grafting time. This article proposes a negative pressure suction seedling positioning method for seed leaves based on the characteristic parameters of cucumber spike wood, and designs a flexible adsorption positioning mechanism for spike wood. Firstly, the ventral surface curve trajectories of cucumber cotyledons were extracted using Matlab software, and then a shape-adaptive design was applied to the attachment surface of the flexible suction positioning mechanism, and a computational fluid dynamics model of the airflow field was established. By combining Fluent simulation analysis with orthogonal experiments, the effect of suction hole diameter, vacuum negative pressure value, suction hole quantity, and suction hole depth on the adsorption effect of the suction head was analyzed, the main and secondary factors and operational indicators that affect the adsorption effect are evaluated. The optimal parameter combination: suction hole diameter of 1.5 mm, vacuum negative pressure value of 2 kPa, suction hole quantity of 42, and suction hole depth of 2 mm, has been found. A verification experiment was conducted on a test bench, and the experimental results show that the success rate of leaf absorption using the optimal parameter combination is 97.69%, which indicates that the suction head is designed reasonably and meets the requirements of grafting.