基于离散元的水田株间除草末端设计与试验

    Design and experiment of intra-row weeding end in paddy fields based on discrete element simulation

    • 摘要: 为实现水田株间高效除草、低伤苗,该研究设计了一种水田株间指状除草末端。在对该末端关键参数进行设计的基础上,基于EDEM建立水、土颗粒堆叠的水田土壤离散元模型,并以此建立水田-末端互作仿真模型模拟除草作业扰动土壤过程,对除草作业时指状除草末端受力情况和泥土颗粒速度场进行仿真分析。采用多因素多水平正交试验,分析前进速度、入土深度、倾斜角度、指折弯角度对指状除草末端性能的影响,得到最优作业性能的参数组合为前进速度1 m/s、入土深度40 mm、倾斜角度30°、指杆折弯角度60°。田间试验表明,平均行、株间除草率分别为80.7%、78.57%,平均伤苗率为4.70%,所设计的株间除草末端能够在保证少伤苗的同时实现有效的株间除草效果,满足株间除草作业的需求。

       

      Abstract: In order to achieve high-efficiency weeding and low seedling injury in paddy fields, this paper designed an intra-row finger weeding end for such environments. The weeding end includes an inter-row hoeing roller and an inter-plant finger weeding end, which are designed according to the operating conditions of paddy field hoeing. The dimensional parameters of the inter-row and inter-plant hoeing end are initially determined, and the working principle of the end is explained. The motion characteristics of the finger weeding end are analysed, and the motion characteristic equation is established. The motion trajectory is plotted and analysed with the Matlab software. The influence of different flexible finger lengths (65 mm, 85 mm and 100 mm) on the motion trajectory is analysed by comparing with different flexible finger lengths. The motion trajectory and analysis, and the analysis of different flexible finger lengths on the finger weeding end of the motion trajectory, were investigated. The influence of different flexible finger lengths was analysed through the comparison of different flexible finger lengths at the finger weeding end of the motion trajectory map. The length of the finger employed for weeding at the finger end of the operation has a significant impact on the trajectory of motion. It is evident that the greater the length of the finger employed for weeding at the finger end of the operation, the greater the area covered by a single finger. Furthermore, it is demonstrated that the greater the length of the finger employed for weeding at the finger end of the operation, the greater the length of the finger. It is evident that the inter-plant weeding area is contingent upon the length of the finger; the longer the finger, the greater the area that can be covered by a single finger of the end of finger weeding. Furthermore, it is evident that the inter-plant weeding area is contingent upon the length of the finger; the longer the finger, the greater the area that can be covered by a single finger of the end of finger weeding. The correlation between finger length and the coverage of the inter-plant weeding area is further elaborated in the subsequent analysis. In order to determine the optimal working parameters of the finger weeding end, and further systematically analyse the effects of different parameters on soil disturbance, weeding effect and soil structure, we carry out the weeding end – paddy field soil interaction simulation, and analyse the inner and outer stresses and soil structure of the finger weeding end, and then select the optimal number of finger rods. The analysis of the force on the inner and outer sides of the finger weeding end and the velocity field of soil particles demonstrates the capacity of the finger weeding end to rotate stably and passively during the weeding operation, thereby ensuring the protection of the roots of rice seedlings from damage. In order to optimise the working performance of the finger weeding end and investigate the primary and secondary factors affecting its working effect, four parameters, namely the forward speed v, depth of entry into the soil d, tilt angle α, and bending angle β, are analysed. The four parameters were analysed in a four-factor three-level orthogonal test, and the optimal parameters were selected with the weed removal rate as the primary objective for optimisation. The optimal parameter combination was determined as v3d3α2β2. The forward speed of 1 m/s, soil penetration depth of 40 mm, tilt angle of 30°, and the bending angle of finger bending angle of 60°.In order to validate the weed removing effect of the weeder end in the real field conditions, a paddy weeder prototype was constructed, and a rice transplanting machine as the prototype. In order to verify the weeding effect of a paddy weeder under real field conditions, a prototype machine was constructed, using a rice transplanter as the power platform, a finger weeding end as the inter-plant weeding end, and a weeding roller as the inter-row weeding end. The field performance test demonstrated that the average inter-row and inter-plant weeding rates were 80.7% and 78.57%, respectively, and the average seedling injury rate was 4.70%. These results indicated that the inter-plant weeding end could achieve an effective inter-plant weeding effect and meet the demand of inter-plant weeding operations while ensuring less seedling injury.

       

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