植物工厂蔬菜穴盘育苗吸针式精密播种装置设计与试验

Design and Experiment of Needle-suction Precision Seeding Device for Plug Seedling Production of Vegetables in Plant Factories

摘要:

针对植物工厂岩棉栽培基质育苗中种子易弹跳、投种区域小导致传统播种设备精度不足的问题，设计一种吸针式精密播种装置。以PLC(可编程逻辑控制器)为控制核心构建控制系统，设计气缸驱动组件曲线轨道实现吸针垂直取、投种;基于ANSYS Fluent仿真获得气室与吸针最优参数（气孔直径为8 mm、间距为205.3 mm），并通过试验确定气室真空压力及适配不同种子的吸针直径。经EDEM仿真，抛物面减速引导面与圆弧方向引导面组合的导种管投种效果最佳。Box-Behnken试验优化结果表明：罗莎绿最优参数为吸种负压5.9 kPa、吸针直径0.6 mm、振动频率44.4 Hz;青梗菜最优参数为吸种负压4.2 kPa、吸针直径0.5 mm、频率42.5 Hz。当生产率为80、100盘/h时，罗莎绿单粒合格指数分别为98.35%、98.08%;青梗菜分别为98.29%、98.11%，满足高精密作业要求，为植物工厂蔬菜穴盘育苗高精度播种装备提供技术支撑。

Abstract:

Aiming to address the low precision of traditional seeding equipment in rock wool substrate seedling cultivation of plant factories caused by easy seed bouncing and small seeding area, a needle-suction precision seeding device was designed. A control system was built with a programmable logic controller (PLC) as the core;a curved track for the cylinder-driven component was designed to enable the suction needle to pick and drop seeds vertically. Based on ANSYS Fluent simulation, the optimal parameters of the air chamber and suction needle were obtained (air hole diameter: 8 mm, spacing: 205.3 mm), and experiments were conducted to determine the air chamber's vacuum pressure and suction needle diameters suitable for different seeds. EDEM simulation showed that the seed guide tube combining a parabolic deceleration guide surface and an arc-shaped direction guide surface achieved the best seeding effect. Box-Behnken experiment-based optimization and verification revealed: for Lactuca sativa, the optimal parameters were 5.9 kPa of seed suction negative pressure, 0.6 mm of suction needle diameter, and 44.4 Hz of vibration frequency;for Brassica rapa subsp. chinensis, the optimal parameters were 4.2 kPa of negative pressure, 0.5 mm of suction needle diameter, and 42.5 Hz of frequency. When the productivity was 80 trays/h and 100 trays/h, the single-seed qualification indices of Lactuca sativa were 98.35% and 98.08%, respectively, while those of Brassica rapa subsp. chinensis were 98.29% and 98.11%, respectively. These results can meet the requirements of high-precision operations and provide technical support for high-precision plug seedling seeding equipment for vegetables in plant factories.