Design and experiment of prescription variable-rate spray control system for boom sprayer

Precision spraying is a key technology in modern agriculture to enhance crop productivity, reduce resource waste, and promote environmental friendliness. As an important method of precision spraying, prescription variable-rate spray control technology is able to realize on-demand precision spraying according to the growth conditions and presence of pests, diseases, and weeds, thereby contributing to water savings, pesticide reduction and efficiency improvement. However, it still faces challenges including low positioning accuracy of spraying, poor variable control precision, and system instability. This study proposed a multi-nozzle position dynamic calculation method and a real-time prescription analysis algorithm. A prescription variable-rate spray control system was developed using a hybrid mode, achieving independent nozzle control for prescription-based spraying. Experimental evaluations were conducted on lateral and longitudinal positioning response distances, deposition stabilization distance, spray volume accuracy, and spray uniformity. The results showed that the system achieved a lateral response distance of 0.10 m and a longitudinal response distance of 0.20 m through prescription positioning analysis. The deposition stabilization distance reached 0.50 m in the lateral direction and 0.40 m in the longitudinal direction. The maximum relative error of spray flow rate was 1.80%, and the maximum coefficient of variation ( CV ) for a single nozzle’s flow rate was 3.10%. The CV for the deposition uniformity was 10.69%. This system realized precise variable-rate spray control based on prescription maps, promoting the advancement of environmentally friendly and efficient plant protection technologies. • A prescription variable-rate spray control system based on Android is developed. • A multi-nozzle position dynamic calculation algorithm is proposed to improve spray positional accuracy. • A multi-sensor fusion method is used to improve spray uniformity and volume accuracy.