An orchard sprayer prototype running a variable-rate algorithm to adapt the spray volume to the canopy characteristics (dimensions, shape and leaf density) in real-time was designed and implemented. The developed machine was able to modify the application rate by using an algorithm based on the tree row volume, in combination with a newly coefficient defined as Density Factor (Df). Variations in the canopy characteristics along the row crop were electronically measured using six ultrasonic sensors (three per sprayer side). These differences in foliage structure were used to adjust the flow rate of the nozzles by merging the ultrasonic sensors data and the forward speed information received from the on-board GNSS. A set of motor-valves was used to regulate the final amount of sprayed liquid. Laboratory and field tests using artificial canopy were arranged to calibrate and select the optimal ultrasonic sensor configuration (width beam and signal pre-processing method) that best described the physical canopy properties. Results indicated that the sensor setup with a medium beam width offered the most appropriate characterization of trees in terms of width and Df. The experimental sprayer was also able to calculate the application rate automatically depending on changes on target trees. In general, the motor valves demonstrated adequate capability to supply and control the required liquid pressure at all times, mainly when spraying in a range between 4.0 and 14.0 MPa. Further work is required on the equipment, such as designing field efficiency tests for the sprayer or refining the accuracy of Df.

设计并实现了果园喷雾机原型，该原型运行可变速率算法，使喷雾量实时适应树冠特征（尺寸、形状和叶子密度）。开发的机器能够通过使用基于树行体积的算法并结合新定义的密度因子系数 (Df）。使用六个超声波传感器（喷雾机每侧三个）以电子方式测量行间作物冠层特征的变化。通过合并超声波传感器数据和从机载 GNSS 接收的前进速度信息，利用树叶结构的这些差异来调整喷嘴的流量。使用一组电动阀来调节喷射液体的最终量。安排使用人造冠层的实验室和现场测试来校准和选择最能描述物理冠层特性的最佳超声波传感器配置（宽波束和信号预处理方法）。结果表明，中等光束宽度的传感器设置在宽度和Df方面提供了最合适的树木特征。实验喷雾器还能够根据目标树木的变化自动计算施用量。一般来说，电动阀表现出足够的能力，能够始终供应和控制所需的液体压力，主要是在 4.0 至 14.0 MPa 范围内喷涂时。该设备还需要进一步的工作，例如设计喷雾机的现场效率测试或改进Df的精度。