Abstract: Traditional spraying does not take into account the individual differences of single crops and regional distribution density differences, resulting in pesticide waste and low application efficiency. Variable spray regulation can effectively improve the pesticide utilization rate. However, the current variable spraying work mainly focuses on continuous spraying, without considering the spraying domain and its range of spray uniformity. To address this problem, the article designs a discrete variable spray control method based on the combination of width regulation and flow rate adjustment. This method collects the target image information through the camera, obtains the radius and position information of the target spraying domain, controls the voltage of the spray pump motor according to this information, thus adjusts the spraying pressure, and combines with the height adjustment of the nozzle to achieve the adjustment of spraying width, thus realizing the adjustment of spraying volume uniformity within the spraying domain. In order to verify the feasibility of this method, a variable spray bench test was built. The bench test showed that the variation coefficient of fog volume distribution was 16.9293%, which was significantly better than 23.7640% of the single control mode, and the variable spray technology could effectively improve the uniformity of fog volume distribution in the spray area. In order to further verify the practicality of this method, a field experiment was carried out with broad bean plants as the test object. The field test showed that changing the DC motor duty cycle to adjust the spray pressure within a certain range could improve the spray distribution uniformity, and when the spray pressure reached 0.5 MPa, the average droplet coverage rate was 29.67%, and the deposition rate was 23.6%, which was in line with the expected effect.

Key words: variable spray, uniformity of spray distribution, target spray field, width, flow rate

摘要： 当前农药变量喷雾技术已考虑到单株作物的个体差异和区域内分布密度的变化，可有效提升农药的利用率。然而，这种技术主要集中于连续喷雾，尚未充分解决喷洒区域及其范围内的喷雾均匀性问题。针对此问题，设计一种基于幅宽调控与流量调整相结合的离散型变量喷雾控制方法。通过摄像头采集目标图像信息，得到目标喷洒区域半径和位置信息，根据此信息控制喷药泵电机的电压，从而调整喷雾压力，并结合喷头高度调节，实现喷雾幅宽的调整，进而实现喷洒区域内雾量均匀性的调节。为验证方法的可行性，搭建变量喷雾台架试验台。台架试验结果显示，采用幅宽调整和流量调控相结合的离散调节方式，雾量分布的变异系数为16.929 3%，显著优于单一调控方式的23.764 0%，表明变量喷雾技术能有效改善喷洒区域内的雾量分布均匀性。为进一步验证方法的实用性，开展以蚕豆植株为试验对象的田间试验。田间试验表明，在一定范围内改变直流电机占空比、调整喷雾压力可提高喷雾分布均匀性，当喷雾压力达到0.5 MPa时，雾滴平均覆盖率为29.67%，沉积率为23.6%，符合预期效果。

关键词: 变量喷雾, 分布均匀性, 目标喷洒区域, 幅宽, 流量