With the ongoing advancement of global agricultural modernization, intelligent technologies have gained significant attention in agricultural production—particularly in the field of intelligent orchard sprayers, where notable progress has been achieved. Intelligent orchard sprayers, equipped with precise sensing and control systems, enable targeted spraying. This enhances the efficiency of crop health management, reduces pesticide usage, minimizes environmental pollution, and supports the development of precision agriculture. This review focuses on three core modules of intelligent sprayer technology: perception and intelligent control, spray deposition and drift control, and autonomous navigation with system integration. By addressing key areas such as sensor technologies, object detection algorithms, and real-time control strategies, this review explores current challenges and future directions for intelligent orchard sprayer technology. It also discusses existing technical bottlenecks and obstacles to large-scale adoption. Finally, this review highlights the pivotal role of intelligent orchard sprayer technology in enhancing crop management efficiency, improving environmental sustainability, and facilitating the transformation of agricultural production systems.

This paper presents an air-assisted sprayer for vineyard pesticide application. The spraying unit was designed with two symmetrically arranged ports. The airflow velocity distribution of the sprayer was investigated using a combination of experimental validation and a computational fluid dynamics (CFD) model. The results of both the simulation and the experiment showed good agreement in airflow velocity, and the distribution was uniform. Both unilateral and bilateral spraying field experiments were conducted in this study. The unilateral spraying experiment showed that higher spray pressure and lower sprayer speed increased both total deposition coverage and spray penetration (SP), while shorter spray distances improved SP but decreased total deposition coverage. The optimal operational conditions for the sprayer were determined as follows: spray pressure of 0.40 MPa, sprayer speed of 0.83 m/s, and spray distance of 1.00 m. The results of the bilateral spraying field experiment indicated that the coefficient of variation (CV) for deposition coverage in Columns A, B, and C were 16.20%, 8.10%, and 15.47%, respectively. The CVs in Layers a, b, and c were 6.14%, 12.62%, and 6.74%, respectively. This result demonstrated that the deposition coverage distribution in the canopy was relatively uniform, and the air-assisted sprayer exhibited good spray penetration performance. This study demonstrates the effectiveness and potential of the air-assisted sprayer for vineyard pesticide application.

Air-assisted sprayers are widely used in orchards due to their efficiency in enhancing droplet penetration and deposition. These sprayers disperse droplets through a high-velocity airflow, which agitates the leaves and aids in canopy penetration. This study involved controlled experiments to simulate leaf movement during field spraying, with a focus on the dynamics of peach tree leaves (Prunus persica) in varying wind fields. An experimental setup consisting of a wind-conveying system, a measurement system, and a fixed system was designed. The moving speeds of the wind field (0.75 m/s, 0.5 m/s, and 1.0 m/s) and wind velocities (ranging from 2 m/s to 8 m/s) were varied. Key parameters, including leaf tip displacement, angular velocity, and twisting amplitude, were measured using high-speed cameras and motion analysis software. The results indicate that, at a constant wind velocity, increasing the wind field’s moving speed resulted in a reduced range of motion, decelerated angular velocity, and decreased twisting amplitude of the leaves. Notably, at a wind field speed of 8 m/s and a moving speed of 1.0 m/s, the twisting duration of the leaves was only 67% of that observed at a moving speed of 0.5 m/s. These findings suggest that wind speed and field motion characteristics play a crucial role in leaf dynamics, informing the design of air-assisted spraying systems.

Traditional methods of weed control during field management often result in herbicide waste. Precision herbicide application is crucial in agricultural production. This study presents a monodisperse droplet-generation system designed for precision herbicide application, capable of generating monodisperse droplets induced by an electric field. Droplet-generation experiments were conducted to investigate the effects of capillary tube outlet shape, liquid flow rate, and capillary tube size on the generation of charged droplets. A droplet diameter prediction model was established based on the system parameters. Experimental results indicated that as the applied voltage increased, the droplet diameter decreased, and the droplet-generation patterns transitioned sequentially from dripping, micro-dripping, to unstable dripping modes. In a weak electric field, capillaries with beveled outlets produced smaller droplets with more stable diameter distributions compared to those with blunt outlets. In a strong electric field, the smallest droplet diameter from blunt capillaries was 138.2 μm, whereas from beveled capillaries it was 198.7 μm. Within the design parameter range, droplet diameter was basically positively correlated with liquid flow rate and capillary tube size. By controlling the applied voltage, liquid flow rate, and capillary tube size, stable droplet generation could be achieved within a diameter range of 198.7–2520.8 μm, and the coefficient of variation of droplet diameter under the same working conditions was generally less than 6%. The monodisperse droplet-generation system developed in this study can effectively reduce herbicide usage and improve application efficiency.

This study evaluates the performance of a novel high-clearance air-assisted electrostatic sprayer designed for vineyards and investigates the impact of applied voltage on droplet deposition. This sprayer, which uses a new type of air-assisted electrostatic spray nozzle, could spray three rows of grapes at the same time, significantly improving work efficiency. Field test results show that the middle row of the high-clearance air-assisted electrostatic sprayer deposition effect was better than the left and right rows, and the minimum droplet deposition density inside the grape canopy was 26.4 deposits/cm². The droplet deposition effects of electrostatic spraying were effectively improved, and the average droplet deposition density of the canopy increased by 15.72%. Electrostatic spraying improves the deposition on the outer canopy but reduces deposition on the inner canopy, so electrostatic spraying reduces the penetration of droplets into the canopy. The sprayer’s design proves effective for large-scale operations, offering insights into electrostatic spray technology’s role in precision agriculture.

This study experimentally investigates the breakup mechanisms and atomization characteristics of liquid jets in subsonic crossflows and develops a penetration depth model that incorporates the incidence angle. Experimental data show that the model fits well, with a minimum R² value of 0.924 and an average of 0.969. High-speed imaging techniques were used to systematically analyze the effects of liquid- and gas-phase Weber numbers and incidence angles on the penetration and atomization of liquid jets. The experimental results indicate the following: (1) As the liquid Weber number (We_l) increases, the penetration depth increases, while the gas Weber number (We_a) is inversely related to penetration depth. (2) A decrease in the incidence angle (ranging from 45° to 90°) significantly reduces penetration performance. (3) As We_a increases, the volume median diameter (VMD) of droplets decreases by 61.70% to 83.09%, while smaller incidence angles cause a 42.96% increase in the VMD. The VMD shows a non-linear trend with respect to We_l, reflecting the complex interaction between inertial forces and surface tension. These findings provide a theoretical basis for understanding the atomization behavior of transverse jets and the key parameters affecting penetration and droplet formation. The results are of practical significance for the structural optimization and performance enhancement of air-assisted atomizing nozzles used in precision agricultural spraying systems.