郑书河, 林长山, 叶大鹏, 刘斌. 巨菌草种茎辊式排种器结构优化及排种动力学仿真与试验[J]. 农业工程学报, 2017, 33(21): 36-43. DOI: 10.11975/j.issn.1002-6819.2017.21.004
    引用本文: 郑书河, 林长山, 叶大鹏, 刘斌. 巨菌草种茎辊式排种器结构优化及排种动力学仿真与试验[J]. 农业工程学报, 2017, 33(21): 36-43. DOI: 10.11975/j.issn.1002-6819.2017.21.004
    Zheng Shuhe, Lin Changshan, Ye Dapeng, Liu Bin. Structural optimization of grooved-roller seed metering device for Pennisetum and simulation and experiment of seed metering dynamics[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(21): 36-43. DOI: 10.11975/j.issn.1002-6819.2017.21.004
    Citation: Zheng Shuhe, Lin Changshan, Ye Dapeng, Liu Bin. Structural optimization of grooved-roller seed metering device for Pennisetum and simulation and experiment of seed metering dynamics[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(21): 36-43. DOI: 10.11975/j.issn.1002-6819.2017.21.004

    巨菌草种茎辊式排种器结构优化及排种动力学仿真与试验

    Structural optimization of grooved-roller seed metering device for Pennisetum and simulation and experiment of seed metering dynamics

    • 摘要: 针对目前巨菌草种植机普遍存在的重、漏播率高、人工劳动强度大、种茎易破损等问题,该文设计了一种槽型辊式排种器。先分析排种过程中的种茎受力状态,推导出种茎的受力角为目标值的函数,确定送种辊入种槽长宽尺寸为20 mm?20 mm;其次,采用弹性垫料改善送种辊排种进程,基于受力角为目标的函数,优化求解得到垫料侧边垫料厚4 mm、底部垫料厚8 mm;最后采用虚拟样机软件ADAMS建立了种茎排种动力学模型,对其排种过程进行仿真,并在此基础上进行了实验室台架试验和田间排种试验。台架试验表明,排种器实现种茎有序地排种,垫料有效地提高排种流畅度;田间试验过程中排种作业稳定,排种合格率均值为93.33%,排种间距变异指数均值为13.63%,平均漏排和重排指数均值为4.1%和2.5%,各项指标均符合巨菌草种植要求。该研究可为同类排种器和巨菌草种植机的研制提供参考。

       

      Abstract: Abstract: A new grooved-roller seed metering device is developed to overcome the breakage of seedling, obtain high sowing rate and raise seeding efficiency in present, and exercise the optimal design. Firstly, this paper introduces the main structure, the working principle and the related structural parameters of the device in detail. Seed metering device is a key component to realize mechanized cultivation of Pennisetum, which is divided into 2 types according to its working principle. One type is real-time cutting seed metering device and the other type is pre-cut seed metering device. Compared with real-time cutting metering device, pre-cut seed metering device has the advantages of high automation, no damage to seed and lower labor intensity, so it shows a good market prospect and is the main trend of the future development of the metering device. The grooved-roller seed metering device is one of pre-cut seed metering devices. In terms of the stem stress state of seeding process, the evaluation function of seeding smoothness with force angle of the stem as the target was derived. According to the function, opening width of the seed groove and depth of the seed groove were the main impact factors of the improved device's seeding performance. Based on the compressive strength of the stem, the best size of seeding slot was deduced as 20 mm × 20 mm finally. The different morphology and difference of seed diameters are the main influence factors of the problem, and those are easy to cause the bud break. The smoothness and accuracy of seeding were improved by adding the elastic dunnages on the groove of the seeding drum. According to the evaluation function of seeding smoothness, the structure size of the dunnages was optimized as the side gasket thickness of 4 mm and the bottom gasket thickness of 8 mm. In order to study the effect of dunnages on the fluency, the model of grooved-roller seed metering device of the Pennisetum was established by using the dynamic simulation software ADAMS (automatic dynamic analysis of mechanical systems). The effect regularities of structural parameters and motion parameters on seed groove and dunnages were studied. The simulations showed that the new seed metering device could realize the orderly discharge of seeds, and obviously reduce the stress of small-diameter seed by using the plastic dunnages, ensuring the seed row stability and the adaptability of seed diameter. Then the real tests in the laboratory and field were undertaken to verify the conclusions of virtual tests. Bench test results showed that the gasket could improve the flow degree of the seed row to a certain extent, in which the roller speed fluctuation ratio was less than 10%, the roller torque fluctuation ratio was less than 400%, and the seeding rhythm fluctuation ratio was about 20%. The research further indicated that the quality of the seeding was not affected by the roller speed, and sometimes the faster speed would slightly improve the fluidity of the seeding. Because when the roller speed was faster, the time the stem entered the entry took shorter, which reduced the resistance of the seed row to a certain extent. The results indicated that the seed metering device can realize the seeding operation and the dunnages can effectively improve the seeding fluency. Field experiment indicated that the seeder was stable, and the qualified index was greater than 93.33%, the missing index was less than 4.1%, the multiple index was less than 2.5%, and the variance coefficient was13.63%. The indicators were in line with the planting requirements of giant grass. The research provides a theoretical reference for the design of grooved-roller seed metering device of Pennisetum and the technical reference for the related design of planting machine.

       

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