Polygonatum is one of the perennial herbs in Chinese medicine, thus leading to a high-value understory crop in agroforestry systems in China. The principal medicinal component can also share the substantial nutritional and therapeutic value. Since the fibrous roots with the inferior nutrition can often interfere with downstream processing, the debearding can serve as the essential preprocessing. However, conventional mechanical debearding cannot fully meet the scalable demand in the ever-growing industry, due to the technical constraints, such as the throughput, root removal, and physical damage to Polygonatum. In this study, a horizontal hexagonal-tumbling debearding device was developed to integrate with the “drying pretreatment followed by mechanical brushing” technology. Several components are included during Polygonatum processing: a rigid frame, support rollers, an independent cage driving system with motor, a hexagonal rotating cage, an internal counter-rotating debearing roller assembly with its dedicated drive, a removable collection bin, a protective dust cover, and a sliding door for operational convenience. Furthermore, the hexagonal cage and the internal debearing rollers were simultaneously yet oppositely rotated to combine the tumbling, impacting, and brushing action on the rhizomes during operation. Fibrous roots were effectively detached to minimize the structural injury in the valuable Polygonatum tissue. A dynamic analysis was also conducted on the architecture and operation under motion and force interaction of Polygonatum within the drum. A systematic investigation was conducted to determine the parameters for high debearding efficiency with low product damage. A three-factor, three-level Box-Behnken response surface design was employed to optimize the performance of the device, with cage speed, debearing roller speed, and feeding rate as independent variables, while debearing rate and breakage rate as the key response metrics. Statistical analysis of variance demonstrated that both cage speed and debearing roller speed exerted a highly significant influence on the debearding rate, while the feeding rate also presented a significant correlation. In contrast, none of the three factors showed a statistically significant impact on the breakage rate within the tested ranges, indicating the effectiveness with minimal damage. Subsequently, response surface analysis further quantified the interactions among these parameters. Their combinations non-linearly influenced the outcome variables. Numerical optimization identified the ideal operational regime as a cage speed of 6 r/min, a debearing roller speed of 90 r/min, and a feeding rate of 7.5 kg/min. The prediction models forecasted a debearing rate of 97.04% and a breakaging rate of only 0.96% under the optimal parameter set. Triplicate tests were conducted to validate the average debearing rates of 96.83% and the breakaging rate of 1.04%. There was excellent consistency with predictions after optimization. The results indicated that the newly developed device significantly outperformed conventional debearding machinery after assessment, in terms of both processing effectiveness and product integrity. Preprocessing quality and efficiency were enhanced in the supply chain, thereby supporting the sustainable scaling, value-added processing, and overall competitiveness of the Polygonatum industry. The findings can provide a solid scientific foundation and practical engineering insights for the specialized, efficient, and gentle processing equipment for Polygonatum and analogous medicinal rhizomes. A valuable framework with pretreatment, mechanical design, dynamic modeling, and optimization can offer for similar technologies in the post-harvest processing of agricultural and medicinal products.

Camellia oil plants have been frequently confined to the low fruit-setting rate, due primarily to their inherent physiological properties and the complex growing environment. The fruit-setting rate can subsequently restrict the yield of camellia oil, thereby impeding the progression and expansion of the camellia oil industry. Fortunately, plant protection drones have been widely used for crop pollination in modern agriculture. It is also the promising prospect of plant protection drones in camellia pollination. This present study aims to clarify the effects of drone-assisted pollination on the fruit-setting rate of camellia oil plants. The DJI T20 model drone was also deployed to conduct the pollination trials. A two-factor and three-level experiment was designed to investigate the influence of flight parameters-specifically different flight heights and speeds-on the droplet spraying patterns of plant protection drones. A comparative analysis was then carried out on the droplet distribution across various experimental groups. The fruit-setting rate of camellia oil plants was calculated after post-drone-assisted pollination. Drone flight parameters were also optimized on the droplet deposition patterns for the high fruit-setting rate of camellia oil plants. The optimal volume of droplet deposition was obtained for the significant sway over the fruit-setting rate. Meanwhile, the flight parameters were determined to fully meet the harsh requirements of camellia oil trees. Experimental and analytical techniques were combined to clarify the relationship between drone flight parameters and camellia pollination for the high yield of camellia oil plants. The results demonstrate that the canopy layer of camellia trees posed a significant impediment to the droplets that were sprayed by the plant protection drones. An inverse relationship was observed between the flight speed and the volume of droplets deposited. There was a gradual reduction in the droplet deposition volume, as the flight speed accelerated. Furthermore, an intriguing trend was noted with respect to the flight altitude. The deposition volume of droplets initially exhibited an upward trend, only to decline subsequently, as the operation height of the drone increased. The optimal pollination was achieved, when the flight speed was calibrated to 3 m/s, and the altitude was set at 2.5 m. The average fruit-setting rate reached 42.67% for the upper canopy of the camellia tree, whereas, for the lower sections of the tree was the rate of 36.00%. Statistical analysis revealed a positive correlation between the fruit-setting rate of camellia trees and the volume of droplet deposition, with the slope K of 25.267 and the adjusted R² value standing at 0.806. Therefore, the feasibility of plant protection drones was verified in the pollination of camellia oil trees. However, there were also some operational nuances. For instance, the resulting airflow was rebounded upon making contact with the ground, if the flight altitude of the drone was set too low. This rebounding airflow was intersected and interacted with the descending airflow, subsequently influencing the trajectory of the droplets during their downward deposition. Such interactions can cause some ramifications on the intended spraying outcomes. Both theoretical and data-driven support was obtained for the application of plant protection drones in the pollination spraying of camellia trees. Some suggestions were also proposed to optimize the subsequent operation of drones in camellia pollination.