Key Technologies for an Orchard Variable-Rate Sprayer: Current Status and Future Prospects

作者：Zhiming Wei, Xinyu Xue, Ramón Salcedo, Zhi Hong Zhang, Emilio Gil Moya, Yitian Sun, Qinglong Li, Jingxin Shen, Qinghai He, Qingqing Dou, Yungan Zhang · 发表于：Agronomy · 年份：2022 · DOI：10.3390/agronomy13010059 · 被引用次数：45 · 研究领域：Plant Surface Properties and Treatments、Smart Agriculture and AI、Insect Pheromone Research and Control

An orchard variable-rate sprayer applies the appropriate amount of plant protection products only where they are needed based on detection data from advanced sensors, a system that has attracted increasing attention. The latest developments in the detection unit, variable control unit, and signal-processing algorithm of the variable-rate sprayer are discussed. The detection of target position and volume is realized with an ultrasonic sensor, a laser scanning sensor, or other methods. The technology of real-time acquisition of foliage density, plant diseases and pests and their severity, as well as meteorological parameters needs further improvements. Among the three variable-flow-rate control units, pulse width modulation was the most widely used, followed by pressure-based, and variable concentration, which is preliminarily verified in the laboratory. The variable air supply control unit is tested both in the laboratory and in field experiments. The tree-row-volume model, the leaf-wall-area model, and the continuous application mode are widely used algorithms. Advanced research on a variable-rate sprayer is analyzed and future prospects are pointed out. A laser-based variable-rate intelligent sprayer equipped with pulse width modulation solenoid valves to tune spray outputs in real time based on target structures may have the potential to be successfully adopted by growers on a large scale in the foreseeable future. It will be a future research direction to develop an intell...