基于EDEM-ADAMS仿真的稻茬地双轴破茬免耕装置研制

针对长江中下游稻麦轮作区的稻茬地根茬量大韧性强、土壤黏度高不宜粉碎等问题,该研究基于仿真试验研制双轴破茬免耕装置。通过EDEM软件建立破茬开沟装置-秸秆-土壤离散元模型,采用正交试验得到破茬开沟装置的刀型、排列方式以及刀具数量,基于EDEM-ADAMS联合仿真,采用单因素试验、正交试验、二次回归正交旋转试验和响应曲面法对甩刀、粉碎装置以及双轴破茬免耕装置进行动力学分析,得到甩刀具参数、旋耕刀轴和粉碎刀轴转速以及双轴轴心水平与垂直高度,得到机具最佳参数：破茬装置选用30把旋耕刀采用双螺旋排列,刀轴转速为286 r/min;粉碎装置选用L型（32把）和直刀（8把）采用双螺旋排列,刀轴转速为605 r/min;双轴水平距离548 mm、垂直高度168 mm。根据最佳参数试制样机并进行田间性能测试。田间试验结果表明,秸秆和稻茬以0.93 kg/m2全量覆盖时,双轴破茬免耕装置对水稻秸秆、根茬的平均切断率以及切茬率分别为95.09%和95.16%,机具通过性良好,田间平均出苗率为95.29%,符合当地农艺要求,适用于秸秆覆盖量大的作业情况。所设计的双轴破茬免耕装置满足长江中下游稻麦轮作区小麦免耕播种作业要求,可为双轴旋转型耕作装置以及根茬不易粉碎、土壤黏度高条件下的免耕播种提供参考。

Development of the biaxial stubble breaking no-tillage device for rice stubble field based on EDEM-ADAMS simulation

Conservation tillage is widely used for the wheat and maize in a dry land. However, the blockage of planters and the low quality of no-tillage sowing have posed a great challenge on to the rice-wheat rotation in the middle and lower reaches of the Yangtze River, due to the heavy soil viscosity, strong root toughness, and a large amount of straw. It is difficult for one-time tillage to meet the requirements of the seedbed. The secondary operations on the soil and stubble of the seedbed also need to improve the soil fluidity of the seedbed for the less blockage of small row spacing crops when sowing, particularly for the effective separation of seed fertilizer and the quality of sowing. In this study, a biaxial stubble stubble-breaking no-tillage device was designed for the rice stubble field using the EDEM-ADAMS platform, according to the milling, impact, crushing, and throwing. A kinematic analysis was made to obtain the trajectories of the rotary and crushing blade shafts. The discrete element model of "the stubble breaking and ditching device-straw-soil" was established by the EDEM software. The optimal parameters of the stubble breaking and ditching device were optimized by an orthogonal experiment, together with the crushing device. The length parameters of the blade were also determined by the single single-factor test. An optimal combination of working parameters was obtained by the quadratic regression orthogonal rotation test and response surface method. Among them, the rotation speed of the rotary and crushing blade shaft, and the horizontal and vertical distance of the two axes were selected as influencing factors, while the number of bond fractures and power consumption were the experimental indexes. Accordingly, a field test was carried out using the prototype. The optimal parameters of the machine were achieved as follows. 30 rotary blades were selected in the double helix arrangement of the stubble stubble-breaking device, where the rotation speed of the blade shaft was 286 r/min. 32 L-type and 8 straight blades in the double helix arrangement were used in the crushing device, where the tool axis speed was 605 r/min. The biaxial horizontal and vertical distances were 548, and 168 mm, respectively, under the maximum number of bonding fractures and the minimum power. The simulation was verified with the above optimal parameters. It was found that the number of bonding fractures was 2 985, and the operating power was 2.65 kW, with the relative errors of 4.39 %, and 2.71 %, respectively. A field experiment was then conducted on the rice stubble field in Hubei Province of China. The excellent passability of the machine was achieved, where the straw coverage was 0.93 kg/m2, the average cutting rate of rice straw was 95.09%, and the average cutting rate of rice root stubble was 95.16%. The average seedling emergence rate was 95.29 % in the field, fully meeting the agronomic requirements of rice stubble fields. Thus, this finding can provide a strong reference for the biaxial rotary tillage device suitable for the stubble difficult to crush and the high soil viscosity during no-tillage sowing.