Measurement of physical contact parameters and discrete element simulation calibration of lettuce seeds
The current level of automation in the sowing process of industrialized lettuce production is relatively low,and designing an automatic seeder suitable for lettuce seed sowing requires simulation.To improve the accuracy of lettuce seed movement in particle simulation software EDEM,the physical parameters and contact parameters of let-tuce seeds were tested.The measured angle of repose of seed pile was used as the validation standard to optimize the calibration of significant impact parameters.By using physical experiments to determine the basic physical properties and range of contact parameters of lettuce seeds,Plackett-Burman test was used to quickly screen out parameters that have a significant impact on the angle of repose of seed pile among multiple factors.Design the steepest climbing test to narrow the range of three significant parameters and determine the three levels of low,medium and high.Then,a second-order regression equation was obtained using the Box-Behnken test,and solved using the measured angle of repose of seed pile as the standard to obtain the optimal combination of EDEM discrete element simulation parameters for lettuce seeds.Finally,the accuracy of the parameters was verified through independent sample T-test.The results indicate that the calibrated optimal parameters can be used for discrete element simulation of the vibration process of lettuce seeds in the seed storage tray,and can also provide reference for the particle parameter setting of fluid solid coupling in precision seedling seeders.
lettuce seedparameter calibrationdiscrete elementangle of repose
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