# Calibration and Analysis of Seeding Parameters of Soaked _Cyperus esculentus_ L. Seeds
## 5 Conclusions  
(1) This study takes soaked _C. esculentus_ seeds as the research object. A three-dimensional model was established based on seeds with a high frequency of length, width, and thickness dimensions. A discrete element simulation model of _C. esculentus_ seeds was constructed using particle auto-filling. Combining physical experiments and EDEM simulation experiments, the restitution coefficient, static friction coefficient, and rolling friction coefficient between _C. esculentus_ seeds and steel plates were calibrated through collision rebound tests and static and kinetic friction measurement tests. The experimental results show that the restitution coefficient of _C. esculentus_ seeds against stainless-steel plates is 0.55, and the static and kinetic friction coefficients are 0.57 and 0.4, respectively.  
(2) Significant parameter screening and optimization: Through the Plackett-Burman experiment, significant parameters affecting the angle of repose were screened for multiple simulation parameters. The experimental results show that the rolling friction factor (F) and static friction factor (E) between _C. esculentus_ seeds have the most significant impact on the angle of repose, followed by the rolling friction factor (J) between seeds and steel plates. The steepest ascent experiment was used to determine the optimal value range for each significant parameter.  
(3) Optimal parameter combination and verification: The Box-Behnken experiment was employed to establish a second-order regression equation for the relative error of the angle of repose. Optimization was performed with the goal of minimizing the relative error of the angle of repose to obtain the best parameter combination: the static friction factor (E) between _C. esculentus_ seeds is 0.675, the rolling friction factor (F) is 0.421, and the rolling friction factor (J) between seeds and steel plates is 0.506. Using this optimal parameter combination for simulation, the average angle of repose obtained is 32.31\({}^{\circ}\). Compared with the results of the physical experiments, the relative error is only 1.1%, indicating that the optimal parameter combination is reasonable. The discrete element simulation parameters calibrated in this study can provide important references for the design and research of precision seeders for _C. esculentus_ seeds.  
Conceptualization, J.Y. and Z.L.; methodology, J.Y.; software, Z.L.; validation, F.L.; formal analysis, J.Y.; investigation, F.L.; resources, F.L.; data curation, J.Y.; writing--original draft preparation, J.Y. and Z.L.; writing--review and editing, J.Y. and F.L.; visualization, F.L.; supervision, J.Y.; project administration, Z.L.; funding acquisition, J.Y. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the Science and Technology Program of the Inner Mongolia Autonomous Region of China (2023 YFHH0012), the Program for Improving the Scientific Research Ability of Youth Teachers of Inner Mongolia Agricultural University (BR230126), and the Key Research and Development Programme Projects in Ordos of Inner Mongolia Autonomous Region (YF20232341).  
Not applicable.  
The raw data supporting the conclusions of this article will be made available by the authors on request.  
The authors are grateful to the editors for immediate processing and the anonymous reviewers for their valuable suggestions.  
The authors declare no conflicts of interest.