Authors

Abstract

To address the issues of poor boom stability and inconsistent spray quality due to harsh field conditions and varying boom height relative to the target, a five-section planar truss boom capable of height adjustment, overall tilt adjustment, and unilateral tilt adjustment was designed. A contour levelling control system for the boom was developed based on the STM32F103 platform. The levelling system uses ultrasonic distance sensors to detect the distance between the boom's ends and the target in real-time. The limit average filtering method is employed to eliminate sudden signal interference and process feedback data. The control system then drives electric actuators to adjust the boom's posture in real-time. Field and spray tests were conducted using a small electric self-propelled sprayer as the test platform. The results indicate that the best levelling performance was achieved with overall height adjustment, overall tilt adjustment, and unilateral tilt adjustment thresholds set to 30mm, 30mm, and 40mm, respectively. The field spray tests showed minimal relative errors in droplet deposition coverage and density on both sides. The coefficient of variation CV of deposition along the boom direction was less than 15%, ensuring good spray distribution uniformity. These findings provide valuable references for the design and optimization of sprayer booms.

Abstract in Chinese

本文设计了一种可实现高度调节、整体倾斜调节、单侧倾斜调节功能的平面五段式桁架喷杆。基于STM32F103平台设计了喷杆仿形调平控制系统，调平系统采用超声波测距传感器实时检测喷杆两侧末端与目标物之间距离，利用限幅平均滤波法以排除突变信号的干扰并对反馈数据进行计算处理，控制系统驱动各机构电动推杆伸缩对喷杆姿态进行实时调整。以小型电动自走式喷雾机为试验平台，分别进行了场地试验及田间喷雾试验，场地试验结果表明当设定整体高度调节阈值为30mm、整体倾斜调节阈值为30mm、单侧倾斜调节阈值为40mm时调平效果最佳，田间喷雾试验结果表明两侧雾滴沉积覆盖率及沉积密度相对误差较小，沿喷杆方向上的沉积量变异系数CV小于15%，可以保证较好的喷雾分布均匀性，研究成果为喷雾机喷杆的设计与优化提供了参考。