光束阻断式小粒蔬菜种子漏充与堵孔同步检测系统研究

针对气力式排种器直播小粒蔬菜种子时易产生漏充与堵孔的问题,设计了一种光束阻断式小粒蔬菜种子漏充与堵孔同步检测系统。该检测系统调用ARM嵌入式系统的中断资源,采用旋转编码器实时测定排种盘转速,实时调整时间窗口与理论脉冲频率;在时间窗口内采集对射型激光传感器的输出脉冲,计算实际脉冲频率;通过对理论脉冲频率和实际脉冲频率实施运算,同步测定漏充率与吸孔堵塞率,并在触摸屏上显示。选用雪白玉萝卜、中双11号油菜和上海青3种蔬菜种子为研究对象,以排种盘转速和吸室真空度为试验因素,以漏充率和吸孔堵塞率为试验指标,在气力式精量排种器上进行该系统与高速摄像同步检测试验验证。试验结果表明,该系统可根据排种盘转速变化自行调整时间窗口,对漏充判断相对偏差不大于1.67%,对吸孔堵塞判断相对偏差不大于0.95%。该方法能够有效实现小粒蔬菜种子漏充与堵孔的实时同步检测,为解析排种器漏播成因与排种器改进设计提供依据。

Design of Synchronous Detection System of Missing Filling Seeds and Suction Hole Blocking Based on Beam Blocking for Small Vegetable Grains

In view of missing filling seeds and suction hole blocking in the seeding process of small grain vegetable seeds in the pneumatic seed metering device, an approach for synchronous detecting the missing filling seeds and suction hole blocking of small grain vegetable seeds was proposed. Using the external interrupt and timer interrupt resources of ARM embedded system, the detection system determined the rotation speed of planter plate with a rotary encoder and adjusted the time window and the theoretical pulse frequency in real time. Then, the detection system collected the output pulse of the laser sensor and obtained the actual pulse frequency. By calculating the theoretical pulse frequency and the actual pulse frequency, the rate of missing filling seeds and rate of suction hole blocking were measured synchronously and displayed on the touch screen. With a synchronous detection by high speed camera system, experimental research on pneumatic precision metering device was carried out with the detection system. The seeds of three kinds of vegetables, such as white radish, middle double 11 rape and Shanghai pakchoi, were selected as the research objects. The test factors were the speed of planter plate and vacuum degree of suction chamber, and the rate of missing filling seeds and rate of suction hole blocking were used as test indexes. Experimental results showed that the system can adjust the time window automatically according to the rotation speed of planter plate. The relative deviation of missing filling seeds rate was not more than 1.67%, and the relative deviation of suction hole blocking rate was not more than 0.95%. This detection approach effectively solved missing filling seeds and suction hole blocking synchronous detection of small grain vegetable seeds in real time and provided a basis for analyzing the cause of seed drain and seeding device improvement design.