整秆式甘蔗联合收获机断尾关键技术的机理研究

Abstract: Sugarcane harvest mechanization is an important way to reduce the sucrose production cost in China and strengthen its international competitiveness. Whole stalk sugarcane combine harvester will still be an important machine model in China for some time due to its adaptability to current production circumstances of countryside and processing conditions of sugar refinery in China. Sugarcane tail-breaking and leaf-stripping are one of difficult obstacles to be solved in the design and production of whole stalk sugarcane harvester. Tail-broken position is difficult to be controlled and the leaf sheaths enclosing the tails are very difficult to be torn and stripped are two key technical difficulties which hinder the tail-breaking and leaf-stripping technology development. In order to solve this two difficulties, In this project, through testing the physical and mechanical properties of sugarcanes tails, the best position of tail-broken will be determined, tails are be broken in this position can meet the agronomic requirements and be suitable for breaking tail by mechanical means. Based on the research, a sugarcane tail-breaking mechanism, which can be fit for whole stalk sugarcane combine harvester, is to be designed, when passing through this kind of mechanism; these tails wrapped closely by these young leaves can be broken in the best position without the need of tearing open or stripping off their sheaths. Truncation error will be small and the leaf stripping difficulty will be greatly reduced while these tails are broken in the best position. Then establish the correlated mathematical and physical model of sugarcane and tail-breaking mechanism, research into the mechanism of tail-breaking. Some methods will be used in the researches; they are physical and mechanical performance experiments, high-speed photography, physical prototype test, theoretical modeling, and so on. These researches will be theoretically and practically significant for the improvement of sugarcane leaf-stripping and tail-breaking device in whole stalk sugarcane combine harvester.

摘要：实现甘蔗收获机械化是降低我国蔗糖生产成本，增强其国际竞争力的重要途径。整秆式甘蔗联合收获机适应我国目前农村生产以及糖厂的加工条件，在一段时间内将会是我国甘蔗收获机研制的重要机型，断尾除叶是这一机型急需克服的难关之一。本项目采用基础力学试验、高速摄影图像分析、物理样机试验和理论建模分析等方法研究甘蔗尾梢的物理力学特性，确定符合农艺要求又适合于机械断尾的最佳断裂位置；研制适用于整秆式甘蔗联合收获机的断尾机构，甘蔗通过该机构时，不需撕裂或破坏紧密包裹蔗尾的叶鞘，在最佳断裂位置断尾，断尾误差小，大大降低剥叶难度；以解决甘蔗整秆断尾过程中断尾位置难以控制和紧密包裹尾部的叶鞘难以撕裂剥除这两个阻碍断尾除叶技术发展的关键技术难点；在此基础上，建立甘蔗与断尾机构之间的关联数学物理模型，深入研究其断尾机理，对于整秆式甘蔗联合收获机剥叶断尾机构的改进有着重要的理论价值和实践意义。

甘蔗整秆断尾过程中断尾位置难以控制和紧密包裹尾部的叶鞘难以撕裂剥除是阻碍整秆式甘蔗联合收获机断尾除叶技术发展的关键技术难点。项目研究了以弯曲折断方式断尾的甘蔗断尾机理及断尾关键技术，大大降低断尾误差和剥叶难度，为我国整秆式甘蔗联合收获机剥叶断尾装置的研制和改进提供一种新的设计理论和方法。采用力学性能试验、高速摄影图像分析、物理样机试验和理论建模分析相结合的方法研究了三个方面的主要内容：.（1）甘蔗尾部物理力学性能以及确定机械断尾的最佳断裂位置；.（2）研制适用于整秆式甘蔗联合收获机的断尾机构，甘蔗通过该机构时，不需撕裂或破坏紧密包裹蔗尾的叶鞘，在最佳断裂位置断尾；.（3）甘蔗茎杆与断尾元件相互作用过程和运动状态；建立断尾力学模型与甘蔗与断尾机构关联数学物理模型，确立了蔗尾弯曲断裂准则以及蔗尾弯曲断裂位置控制方程。.研究主要结论：.（1）弯曲破坏是机械断尾的一个可行方式，甘蔗尾部茎秆顶端生长点以下约第5节的位置是甘蔗茎秆未成熟尾部与已成熟茎部接合处的脆弱部位，也是机械断尾的最佳断裂位置。最佳断裂位置的抗弯强度显著低于中部和基部，并向蔗茎顶端生长点处逐渐减弱；最佳断裂位置的节间部分抗压强度为4.61MPa，标准误差为0.27MPa；压缩弹性模量为62.91MPa，标准误差为8.63MPa。抗弯强度为9.40 MPa，标准误差为0.46 MPa；弯曲弹性模量为55.85 MPa，标准误差为4.86 MPa。.（2）本项目设计的断尾机构，甘蔗通过该机构时蔗尾在最佳断裂位置附近断裂，断尾误差小，对比本实验室剥叶装置试验结果，本项目设计的断尾装置能够大大降低剥叶难度、有效降低剥叶滚筒的转速。同一时刻对蔗茎施加正压力的断尾弹性元件的数量和正压力的大小，以及断尾弹性元件与蔗茎的接触频率是蔗茎通过断尾滚筒工作区域时能否断尾，断尾的长度是否合理的关键。.（3）根据断尾机构与甘蔗数学物理模型及蔗尾弯曲断裂控制方程，选定速度比（蔗茎前进速度/断尾弹性元件顶端线速度），选择断尾机构各参数满足断裂准则，可实现在最佳断裂位置断尾。