Abstract: In order to improve the problems of environmental pollution and chemical residue caused by pesticide waste during the spraying operation of maize crops, a sub‑controlled variable spray control system was designed. The STM32 single‑chip microcomputer was used as the control core of the system ,collecting the travel speed of the tool and the actual spray pressure at the upper and lower nozzles of the lifting rod with the pressure sensor and speed sensor, through the method of artificially giving the theoretical pressure value by the user, the single‑chip microcomputer compared the relationship between the actual pressure value and the theoretical pressure value and then adjusted the opening of the electric control valve at the upper and lower nozzles of the lifting spray rod, so as to realize the spray pressure at the upper and lower nozzles of the lifting rod with the travel speed change spray. The results were obtained by constructing physical tests as follows: the average relative error of upper nozzle spray flow was 2.59%, the average relative error of lower nozzle spray flow was 2.87%, and the average relative error of upper nozzle spray flow and lower nozzle spray flow in variable speed test was 2.6% and 3.11% respectively. The test results show that the software and hardware design of the control system are reasonable, and the control accuracy can meet the requirements.

Key words: corn, environmental pollution, microcontroller, control system, variable spray

摘要： 为改善玉米作物吊施喷雾作业过程中农药浪费造成环境污染及药液残留的问题，设计一种分控变量喷雾控制系统。系统以STM32单片机为控制核心，以压力传感器与速度传感器采集机具行进速度与吊喷杆上、下喷口处实际喷雾压力，通过用户人为给定理论压力值的方法，单片机比较实际压力值与理论压力值的关系进而调整吊喷杆上、下喷口处电动调节阀的开度，实现吊喷杆上、下喷口处喷雾压力随行进速度变化喷雾。试验结果表明，恒速试验中上喷头喷雾流量平均相对误差为2.59%、下喷头喷雾流量平均相对误差为2.87%，变速试验中上喷头喷雾流量平均相对误差为2.6%、下喷头喷雾流量平均相对误差为3.11%。控制系统软件与硬件设计合理，控制精度可达到要求。

关键词: 玉米作物, 环境污染, 单片机, 控制系统, 变量喷雾