果园喷雾机自动对靶喷雾控制系统研制与试验

为提高农药利用率,减少环境污染,该文针对中国果园机械化作业条件差和传统果园喷雾机连续喷雾时存在果树间空隙无效喷雾的特点,设计了自动对靶喷雾控制系统,该系统以GY8履带自走式果园喷雾机为载体,采用传感器测距方式探测果树,实现自动对靶喷雾。通过对超声波、红外和激光3种传感器进行性能比较,及对超声波和激光2种传感器进行静态识别间距测试与分析,红外传感器受光强影响较大,超声波传感器识别间距超过800 mm,均不满足果园精确对靶喷雾控制要求,激光传感器静态识别间距只有20 mm,具有工作稳定、响应快速、方向性好等特点,故将激光传感器选为自动对靶喷雾机探测装置,并将激光传感器安装于喷头组件前方220 mm。采用连续3次检测靶标判别法设计了自动对靶喷雾系统,该系统可有效避免因激光光束较细而导致的将树冠内空洞、枝间间隙等误判为果树间空隙而出现的电磁阀频繁启闭动作。行驶速度为0.5 m/s时,自动对靶喷雾控制系统的动态靶标识别间距介于100~150 mm之间,行驶速度1.0 m/s时,动态靶标识别间距为200~250 mm。此外,该系统还具有提前及延后喷雾功能,自动对靶喷雾系统提前靶标95.0~157.5 mm距离开始喷雾,离开靶标100 mm距离停止喷雾,使喷雾完全覆盖整个树冠。与连续喷雾相比,对靶喷雾可有效节省施药量,对于空隙比为20.0%、35.2%、52.9%靶标行枣树,行驶速度为0.5 m/s时省药率分别达27.9%、53.7%、76.9%,行驶速度为1.0 m/s时省药率分别达27.3%、54.5%、81.0%。因此,该自动对靶喷雾系统对稀疏果园的精确对靶病虫害防治具有较好的实用价值。

Development and experiment of automatic target spray control system used in orchard sprayer

Abstract: In order to improve the utilization rate of pesticides and reduce the pesticide pollution to the environment, the control system of the automatic target spray was designed to focus on a Chinese low level of mechanization about the orchard sprayer and the invalid spray existed in the gap of fruit trees when the orchard sprayer sprayed with a continuous spray method. Whether the automatic target spray system sprayed to the fruit trees, depended on the detection distance between the orchard sprayer and the fruit trees by the application of distance measuring sensors and control program, which was installed on the GY8 caterpillar self-propelled orchard sprayer manufactured by Nantong Guangyi Mechanical & Electrical Co, Ltd. This paper compared the properties of three kinds of sensors which were MB7060 ultrasonic sensor, GP2Y0A710K0F infrared sensor and DT35-B15251 laser sensor, and tested the discernible spacing for the ultrasonic sensor and the laser sensor. The laser sensor was chosen as a detection device of the orchard sprayer for its high stability, fast response and good direction, while the other two sensors were abandoned for the following reasons that the infrared sensor was seriously affected by the sunshine, and the discernible spacing of ultrasonic sensor was too wide to satisfy the working conditions of the orchard sprayer. The parameters of the target range for spray trees could be adjusted in the system of the automatic target spray, based on different planted size (spacing in the rows and spacing between rows) of an orchard and the different travel speed of the orchard sprayer. The automatic target spray system could distinguish whether the fruit tree, or the gap between fruit trees and the gap in the canopies, so as to effectively control pests with the minimum dose of pesticide and the least environmental pollution. To ensure that the droplet could cover the whole canopy, the orchard sprayer must start to spray before the nozzle assembly reached the fruit trees and stopped spraying after the nozzle assembly leaves the fruit trees, so the laser sensor was installed in front of nozzle assembly 220 mm and delayed a period of time on the basis of the travel speed to stop spraying after the nozzle assembly left the fruit trees by calculation. The experiment of the discernible spacing of the automatic target spray system and field experiment was tested in the Jiamu forest farm in Aksu of Xinjiang. The results showed that the value of the minimum discernible spacing was lower at higher travel speed to lower travel speed. The discernible spacing of the automatic target spray system was 100-150 mm under the travel speed 0.5 m/s and 200-250 mm under the travel speed was 1.0 m/s. The saving rate of pesticides increased with the increase of the gap rate. Compared with continuous spray, the automatic target spray could save pesticides 27.9%, 53.7%, 76.9 % at the travel speed of 0.5 m/s and 27.3%, 54.5%, 81.0% at the travel speed 1.0m/s, respectively for the gap rate 20.0%, 35.2%, 52.9%. The saving rate of pesticides was higher than the gap rate of the fruit trees, because the pressure of the spray unit was low as the pesticide valve on initially. It is a favorable condition to save pesticide corresponding to thin canopy. Thus, the automatic target spray system of the orchard sprayer could effectively improve the utilization rate of pesticides.