玉米种子低损伤仿生脱粒机理研究

Mechanical damage of corn seeds that threshing machinery gives rise to will bring serious influence for storage and production. It is the main influencing factor for threshing method that gives rise to mechanical damage of corn seeds. Because of existence of circulating dint circle between corn kernels, traditional impacting sheller can not be satisfied with the request of low broken rate of corn seed. According to research of some birds pecking corn ear and mankind threshing process of corn ear by bare hand , the results showed that some birds’ wedge beak not only have good ability of inserting kernel cleft and loosening and separating big scope of kernels, but also have stronger ability of pecking corn kernel, corn kernel have no damage; the bionic threshing process of corn ear by bare hand can effectively break circulating dint circle between corn kernels, corn kernels are threshed with different speeds threshing parts in order, have a low damage rate and high clean-threshing rate. The item will begin with research of mechanical damage of corn seeds, pass analysis of mechanism of some birds pecking corn ear and mankind threshing process of corn ear by bare hand and a series of experiments of biological and mechanical properties of circulating dint circle between corn kernels, and find out the relation between low damage bionic threshing and declining law of circulating dint circle, build up wedge loosening and separating theory that some birds’ beak loosen and separate corn kernels and theory of tearing down a row of corn kernel with different speeds threshing parts that man threshes corn ear by bare hand, then put forward the new method of low damage threshing of corn seed.

机械损伤的玉米种子会给储存和生产带来严重的影响，种子的机械损伤是由脱粒机械所引起。 脱粒方法是影响其机械损伤的主要因素。由于玉米穗上籽粒间“循环力圈”的存在，使得传统冲击式玉米脱粒机不能满足玉米种子低破碎率的要求。根据对某些鸟类啄食玉米果穗及人类手工脱粒过程的研究发现:某些鸟类的楔形喙部不仅具有优良的切入籽粒间隙离散大片籽粒的能力，还具有较强的啄取籽粒能力，离散下的籽粒无损伤；仿人手脱粒，能有效破坏籽粒间“循环力圈”，籽粒按顺序差速脱粒，损伤低，脱净率高。本项目从研究玉米籽粒的机械损伤入手，通过鸟类喙部离散玉米、人类手工脱粒玉米的机理分析,以及玉米籽粒间“循环力圈”的生物学、力学特性等系列试验，找出玉米果穗籽粒低损伤仿生脱粒与籽粒间循环力衰败规律之间的关系,建立起鸟类喙部离散籽粒的“楔形离散”理论，以及人手脱粒籽粒的“差速倒排”理论，进而提出低损伤玉米种子脱粒的新方法。

玉米种子脱粒是收获工作中的关键环节，它决定了玉米种子的破损程度，是保证玉米丰产丰收的一个关键环节。 .目前，我国玉米种子脱粒仍采用普通商品玉米脱粒的机型，以靠钉齿或窄板齿高速打击玉米果穗而脱粒，籽粒破损大，严重影响了种子发芽率和玉米产量，并且不符合精密播种等精细农业的发展要求。. 为找出玉米种子低损伤脱粒的新方法，以改进玉米种子脱粒技术，本项目运用了有限元分析方法、图象处理技术、高速摄影法、显微分析法、仿生设计方法与实验法等方法，主要进行了以下研究：（1）玉米果穗生物力学特性分析（2）玉米果穗籽粒间力学特性研究；（3）玉米果穗裸手低损伤差速脱粒机理；（4）鸡喙的生理特性与微观分析；（5）鸡喙几何特征量化分析；（6）鸟类喙部低损伤离散玉米果穗机理；（7）玉米种子低损伤仿生脱粒方法；（8）根据玉米种子低损伤仿生脱粒原理研制了玉米果穗多辊脱粒机并进行了试验。.项目取得的主要成果：（1）揭示了籽粒间组砌规律及外力作用下籽粒间循环力消弱机理；（2）获得了玉米籽粒间缝隙走向对其循环力衰败影响规律（3）发现了玉米果穗离散效果与含水率、冲击头作用力等因素之间的规律；（4）揭示了玉米果穗裸手低损伤差速脱粒机理；（5）提出了裸手脱粒籽粒的“差速倒排”理论；（6）揭示了鸟类喙部低损伤离散玉米果穗机理；（7）提出了鸟类喙部离散籽粒的“楔形离散”理论；（8）提出了基于先离散后脱粒的玉米种子低损伤仿生脱粒新方法。（9）研制了基于先离散后脱粒的玉米果穗多辊脱粒机。. 本项目涉及仿生学、农艺学和机械学等多个学科，揭示了外力作用下籽粒间循环力消弱机理，研究低损伤仿生脱粒方法并指导改进脱粒技术，对于降低玉米种子加工损失，提高种子的质量和品质是有现实意义的。