玉米根茬起铺机关键部件试验研究

【作者】 于泳红；

【导师】 王俊发； 周欣；

【作者基本信息】 佳木斯大学 ， 农业机械化工程， 2011， 硕士

【摘要】 本文采用理论分析、试验研究与计算机仿真分析的方法,对玉米根茬机械化收获减阻挖掘理论、低功耗挖掘技术进行了较深入的研究。以低功耗、确保根茬完整性为目标,设计了楔形挖掘铲和捡拾轮组件。对关键部件挖掘铲进行了有限元分析,对单铲挖掘阻力进行了室内土槽测定,得到了0.3~0.9m/s水平前进速度下挖掘阻力功耗及挖掘阻力频谱,分析了影响挖掘功耗的主次因素,确定了低功耗挖掘最佳参数组合。在试验基础上对整机关键部件捡拾轮的运动特性及整机功能进行了计算机仿真研究,实现了以楔形铲、弯弧捡拾轮齿为关键部件的玉米根茬收获虚拟样机运动仿真。并制做了玉米根茬收获机物理样机,完成了田间试验验证。通过对玉米根茬的生长特性、空间分布规律及减租理论的研究,给出了玉米根茬的结构参数,确定了挖掘铲的主要结构参数。建立了铲的有限元模型,借助ANSYS软件,对铲与土壤作用进行了静力学和动力学模态分析。分析得出铲面垂直载荷最大应力集中在铲面连接螺栓处,和挖掘铲固有频率从一阶模态67.414Hz至六阶模态频率为700.53Hz升高的变化规律,不会引起共振,损害挖掘铲。分析了关键部件捡拾轮齿尖相对运动轨迹,研究了根茬捡拾特性,抛茬性能及条件。计算出捡拾轮齿弯弧角度为1 05°和最低捡拾位置角40°。采用自制的传感器,运用六分力阻力测定方法,对挖掘铲进行了室内土槽单铲挖掘阻力及功耗多因子多水平测定,用vib′sys软件得到了阻力频谱及阻力功耗值。用expert-design正交试验软件对试验结果进行了多因子交互作用及各单因素对挖掘功耗的影响分析,确定了低功耗挖掘影响因素主次顺序及最优组合为0.45m/s的前进速度,5 2.7°的铲安装角和27 .5°铲面倾角。得出了各因素及其交互作用对功耗影响方程。土槽功耗试验进一步验证了挖掘铲设计的合理性。设计了玉米根茬收获虚拟样机,采用Pro/E软件对虚拟样机工作机构进行了运动过程仿真分析,并借助3DS MAX软件对作物根茬收获虚拟样机的收获工艺过程进行了仿真研究,为物理样机的试制提供了参考和依据。更多还原

【Abstract】 This article shows a deep study of the theory on reducing excavating resistance、low-power excavating technology with the methods of theoretical analysis、experimental research and computer simulation. For the target of low power consumption to ensur the integrity of root stubble, wedge excavating shovel and picking up wheel components are designed. Finite element on the shovel is analyzed and a excavating resistance of single shovel is measured indoor soil bin, also with excavating resistance power and fresistance requency spectrum at the forward speed of 0.3~0.9m/s is obtained. The primary and secondary factors influencing on excavating resistance prower are analyzed and the most suitable combination of thoese factors of the lowest prower are obtained. Basing on experiments, this article offers a motion characteristics simulation study on computer about picking–up device and the whole machine function. Virtual prototype design and motion simulation of corn root stubble harvest which is made up of thoese two key components by wedge shovel and curved picking up finger picking-up device n are achieved,also with corn root stubble physical prototype is made and field experiments verification is completed.According to the study of corn root stubble growth characteristics、distribution pattern in spatial space and root soil composite mechanical properties,the structure parameters of corn stubble is offered and the main structure parameters for the shovel is determined.The finite element model of shovel is established, and its finite element static and dynamic mode analysis of excavating shovel when it working with soil is offered by software ANSYS. The result verified that the maximum principal stress of vertical load at shovel surface is located on the connecting nut. ,and it’s natural frequency from mode one 67.414Hz to mode six 700.53Hz is obtained ,It is far from sub soiling vibration frequency 8-12Hz in normal, this result can,t damage to the shovel. Also relative motion trajectory for the tip of picking up wheel finger is analyzed, and picking characteristics of the stubble, casting stubble performance and condition is studied. Also with the angle of 105 0for no-casting picking、the lowest position angle 40 0is calculated. .Using self-made sensor, contributing to six component force resistance measuring method, the resistance of single shovel for excavating indoor bin together with resistance power for multi-factor or multi-level is measured.Then by vib’sys software, resistance frequency spectrum and numerical values of resistance power is obtained. In this paper, the interactions of Single factor and multi-factor and influence of various factors on excavating shovel power depending on orthogonal experimental expert-design software. is analyzed. The order of primary and secondary factors of lowest excavating power and is determined by installation angle、forward speed and angle of dip for the shovel surface. and the best combination factors of the lowest resistance power:forward speed is0.45m/s、installation angle is 52°and angle of dip for the shovel surface is 27.5°.Power equation is obtained. Soil bin experiment further verified the design of excavating shovel is reasonable.Harvest of corn stubble prototype is designed. using Pro/E software, the movement process simulation analysis for agencies of the corn root stubble virtual prototype is achieved and with the 3DS MAX software, virtual prototype of crop stubble harvest harvesting process is simulated , making a reference for the trial of physical prototype更多还原