精密播种机土壤工作部件的振动控制研究

Vibration Control Study on Soil-Engaging Machine Components of Precision Seeder

功率谱密度函数是描述随机振动的一个重要参数,它使我们知道哪些频率的功率是主要的。通过对功率谱密度的研究,有助于理解振动的物理机理,以便进行随机振动控制。该项研究的目的在于控制精密播种机土壤工作部件小幅度输出功率谱密度,获得适合农业技术要求的田间植株分布。通过分析自功率谱峰值点的起因了解到,峰值点主要受传递函数H_(1a)(ω)、自功率谱密度函数G(ω/Ω)以及cosωτ_L的影响。在这一基础上设计了避开峰值点的作业速度和阻尼消振装置,仿形补偿装置,同时进行了室内土槽试验和田间生产试验,试验表明在田间作业速度为9.05 km/h,平均播深为4.88 cm时,最大播深变异系数仅为13.4％。

Power spectrum density function is one of the main parameters used to describe random vibration. It tells the main affecting frequency. A study on the power spectrum density would reveal the physical principle of vibration and some methods to control random vibration could be found. This study was aimed to control small amplitude output power spectrum density of soil-engaging machine components of precision seeder in order to obtain an ideal field seed distribution to meet with agricultural requirements. Results showed that the peak value of self-power spectrum was mainly affected by the transmission function H1(w) ,the self-power spectrum density function G(w/ ) ,and cosw . Based on the study, rubber depth band, rubber presswheel, bumpers made of air spring and profiling compensation devices were developed. By using those components together with a certain working speed,the peak value point could be avoided. The indoor soil bin test showed that the theoretical study was in consistent with the experiment. It also proved that bumper and profiling compensation device were important for decreasing vibration and stabilizing seeding depth. A field production trial was also conducted under the condition of prepared seed-bed. Results showed that the coefficient of variation of seeding depth was only 13. 4% with the average seeding depth of 4. 88 cm under 9. 05 km/h seeding speed. The field seedling counting showed that the components were beneficial to maintain evenness of seeding depth and also good for water conservation,especially under dry conditions.