| Due to the problem of the rate of Garlic bulbil with upward direction and upright degree is easy to become lower after mechanical sowing in china recently,the physical and geometric parameters of Cangshan garlic were measured,and the discrete element method was used.And the dynamics model of mechanism with double duck bill shape was established.In adjusting the garlic portion,the simulation studied the movement law of garlic in three kinds of garlic adjusting mechanism and different factors' influences on the rate of garlic bulbil with upward direction such as the different curves of duck bill,the gravity of garlics,the speed of seeding and the secondary bouncing of garlics.Besides,it also studied the principle of adjusting the garlics to upward direction.The indoor planting test-bed and the field prototype were manufactured.The seeding experiment was carried out,and the dynamic images of garlics' movement at one point were recorded by visual method.It was found that the result was consistent with the simulation process,and the deviation between the rate of garlic bulbil with upward direction of the experiment and that of the simulation was less than five percent.The results show that it is effective to use the discrete element method to analyze the movement of garlics during sowing.The rate of garlic bulbil with upward direction of the test in field can up to 95.67%,an increase of 4.67 percentage points.In the implant link of garlic mechanical sowing,under the strong coupling effect of garlics,soil and soil-engaging components,upright degree of garlic after the adjustment is easy to become lower,“implantation with maintained posture” becomes the key technology to be solved urgently.Aiming at this problem,the discrete element model that could accurately simulate the process of inserting and seeding was established by taking the double duckbill garlic planter as the research object and taking the postures of garlics and section profile of garlic hole after the experiment as calibration basis.The fact that refluxing soil's clamping and maintaining posture towards interference-free inertial fall garlic was the key of ensuring the high upright degree after planting was clearly illustrated.The Box-Benhnken central composite experimental principle was adopted to conduct a three-factor and three-level quadratic regression experiment design towards the speed of inserting and seeding,opening phase angle and opening speed ratio.The simulation experiment of seeding was conducted,and the mathematical model of response surface was established.It was obvious that the significant effects of the opening speed ratio,the speed of inserting and seeding and the opening phase angle on the mean value and the variance of the upright degree were in a decreasing order.Comprehensive optimization towards parameters was conducted by the overall planning operation efficiency and quality,and 4 groups of the optimal work parameter combination was obtained.The laboratory and field test showed that the mean upright degree and the mean variance relative error were 7.2% and 10.6%,which indicated that the predicted results of the model were consistent with the practical results.Meanwhile,the field experiment,in which the working speed of the machine was the same as that of the 4 groups of the field experiment with the optimal working conditions but the opening speed ratio and the opening phrase angle were different,was conducted.The results showed that the mean value of the upright degree increased by 21.8% after the optimal working condition operated,which indicated that the established model could be used in the optimization of the working condition parameter of garlic seeding. |
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