芝麻精量穴播排种器吸种性能分析与试验

Seed suction performance and experiment of sesame precision hole seeding metering device

针对芝麻人工种植效率低、出苗后间苗定苗费工费时且劳动强度大、缺乏适用的精量穴播排种器等生产实际问题,采用负压吸种、正压投种的正负气压组合排种原理,构建了排种器吸种过程临界负压模型,分析了种子吸附的不同姿态及其与型孔接触面积的关系,采用多目标优化方法,得到了型孔吸附1~4粒种子的临界负压,确定实现芝麻精量穴播的较优型孔直径范围为0.8~1.1 mm。吸种运移状态图像拍摄试验结果表明:芝麻不同吸附姿态及概率为横卧:侧卧:直立≈3.5:1:1,排种器不同吸种数目所需负压变化规律与临界负压模型一致。通过基于响应面优化试验考察排种盘型孔直径、排种轴转速和气室负压真空度对穴粒数合格率、漏播率和重播率的影响规律,试验结果表明:型孔直径为1.0 mm、气室负压为-800 Pa、排种轴转速为8.66 r/min时,穴粒数合格率为96.04%、漏播率为0.21%、重播率为3.75%,满足芝麻种植农艺要求。

A critical negative pressure model of seed suction process of metering device was established with the principle of combined seeding with negative pressure suction and positive pressure injection to figure out the practical problems of sesame production including low efficiency of artificial planting,time-consuming and high labor intensity of thinning and setting seedlings after emergence,and lack of suitable precision hole metering device.The different posture of seed suction and the contacting area between seed and pore was analyzed.The critical negative pressure of 1-4 seeds adsorbed by the hole was obtained with the multi-objective optimization method.The optimal hole diameter range of sesame precision hole sowing was determined to be 0.8-1.1 mm.The results of the image shooting test of the seed suction and transporting state showed that the different adsorption posture and probabilities of sesame was horizontal lying:side lying:upright≈3.5:1:1.The variation of negative pressure required by different number of seed suction was consistent with the critical negative pressure model.The optimization test based on response surface was carried out to analyze the effects of the diameter of metering disc hole,rotation speed of seed metering device and negative pressure of air chamber on the seed metering performance including the rate of qualified number of seed in the hole,the rate of missed seeding and the rate of multiple seeding.The results showed that the rate of the qualified number of seeds in the hole,the rate of missing seeding,and the rate of multiple seeding was 96.04%,0.21%,and 3.75%when the diameter of metering disc hole,the negative pressure and vacuum degree of the air chamber,and the rotation speed of the metering shaft was 1.0 mm,-800 Pa,and 8.66 r/min,meeting the agronomic requirements of sesame planting.It will provide a reference for improving the structure of sesame precision hole seeding metering device.