摘要
基于鸵鸟足底附着特性的越沙轮面仿生研究沙漠石油开采和深空探测等沙地环境都需要车辆或探测车在沙地上具有良好的通过性，但是沙土的内聚力小且有流动性，极易导致车辆在沙地上的通过性差，甚至无法通过。轮面作为沙地环境中车辆和沙地相互作用的关键车轮部位，在提高车辆在沙地上的通过性方面起着至关重要的作用。鸵鸟能够在沙地上快速的奔跑，其足底在沙地上具有良好的附着特性，通过对鸵鸟足底的附着特性进行研究，运用工程仿生学技术，设计了一种性能优越的仿生越沙轮面，对提高车辆在沙地上的通过性提供了重要参考价值。
借助体视显微镜和扫描电镜对鸵鸟足底附着物—乳突群，进行了宏微观研究，在宏观方面，乳突尖端由3-5圈状的层叠结构组成，且在已磨损乳突群中发现了新生乳突，这种圈状的结构和乳突再生能有效的保护鸵鸟足底皮肤不被损坏。在微观方面，单根乳突为中空结构，推测这种中空结构能阻碍热量从沙漠中高温的沙土介质传递到鸵鸟足底皮肤；单根乳突的纵切面可以看到乳突由许多细小纤维相互交错组成，这种结构能增大乳突的抗拉强度和耐磨特性。对于单根乳突，乳突从根部到尖端，宏观结构越来粗糙，而微观结构越来越平整，根据乳突和地面的接触频率可知宏观越粗糙，微观越平整的结构更耐磨。将鸵鸟足底划分10个区域，对每个区域中的乳突数量和尺寸进行统计，简化各区域中乳突方向分布，将这些数据作为仿生越沙轮面凸体设计的依据。
设计了一套动物足底和沙土间附着系数多角度测量装置，并论述了该装置的测量原理，计算了装置中摩擦较大位置处的摩擦力，完成装置的标定。测量了木材与铁和橡胶与铁之间的附着系数，并与已知的参数进行对比，试验表明测量数据和参考数据接近，验证该装置设计合理。在“0度位置”测量了鸵鸟足底在单层沙板上的附着系数，附着系数的测量范围在0.64-0.9，附着系数非常大，表明鸵鸟足底在单层沙板上具有良好的附着特性。在一个圆周方向每隔10度测量鸵鸟足底和200mm厚度的石英砂上附着系数，并对附着系数最大的位置和最小位置对应的工况进行了受力分析，测量表明，对应鸵鸟制动工况的“180度位置”附近是附着系数最大的位置，对应鸵鸟的启动或者直线运动工况的“0度位置”附近是附着系数最小的位置，而对应于鸵鸟转向工况的其他位置附着系数则介于这两个位置之间。附着系数最大的鸵鸟制动工况位置将作为仿生设计的主要位置依据。通过鸵鸟足底有无乳突的对比试验表明，鸵鸟足底乳突能显著增加附着特性。
用手持式三维扫描仪获得鸵鸟足底曲面，并用Geomagic Studio和CATIA软件处理，获得鸵鸟足底轮廓曲线。基于该轮廓曲线和前期鸵鸟足底乳突群测量数据，设计了表面有多种凸体的仿生越沙轮面单体。通过离散元软件EDEM数值模拟，比较附着力的大小，结合正交试验设计，对仿生轮面凸体的尺寸进行优化设计，最终获得凸体宽度（直径）、间距和高度都为2mm的仿生轮面的附着特性最好。基于轮面凸体的最优尺寸，制造出仿生和常规越沙轮面单体，进行正向拉板试验和逆向拉板试验。试验
结果都表明仿生越沙轮面单体的附着特性要好于常规越沙轮面单体；试验结果还表明，基于乳突的凸体必须和基于鸵鸟足底的轮廓相配合才能具有良好的附着效果。将仿生越沙轮面单体和常规越沙轮面单体的三维模型通过阵列获得整轮模型，将模型导入EDEM软件中比较两种轮面的土壤推力，模拟结果表明，仿生越沙轮面的土壤推力要比常规轮面的土壤推力大113.4%，表明仿生越沙轮面有更好的越沙能力。仿生越沙轮面研究将为高通过性越沙轮面设计提供新的思路和设计参考。
关键字：
鸵鸟足底，乳突，附着特性，越沙轮面，仿生设计，数值模拟
Abstract
Bionic Rearch in Surface of Traveling-Sand Wheel Bad on the
Adhesion Property of Ostrich Planta
It is esntial to have a good traveling ability on sand for a car when they are working for exploiting oil on dert or exploring on deep space. But cars always have an inferior traveling ability even land themlves in sand becau the cohesive force of the sand is small and the sand can flow easily. As the only part of the wheel, the surface of the wheel play a key role in improving the traveling ability o
n sand. Ostrich can run fast on sand, the planta of ostrich have a good adhesion property on sand. A bionic surface of wheel was designed bad on the planta of ostrich, which have a significance on improving traveling ability of car on sand environment.
对大数据的认识Stereomicroscope and Scanning Electron Microscope were ud to obrve the plantar papillae of ostrich. In macro level, a single papilla was compod by 3 to 5 circular layered structure. Newborn papillae were found among old papillae. Tho newborn papillae and layered structure can prevent the plantar skin from abrasion. In micro level, the single papilla was hollow. We inferred that this structure can impede the conductor of heat from the sand on dert. From the vertical ction, single papilla was compod by interlocking fibers. Tho fibers can increa the strength of extension and wear-resistance property. From the root to the tip of a single papilla, the macro structure became rougher, but the micro structure became smoother. We also surmid that tho structure can contribute a lot for wear-resistance. The planta of ostrich was divided to ten parts artificially. The size of papillae were collected which would be ud on later bionic design.
An equipment was designed and manufactured for measuring adhesion coefficient between the planta of animal and substrates on the land. The principle of this equipment was reprented and some force of friction was calculated. Adhesion coefficient between wood and steel, rubber and steel
were measured to compare with reference data to finish the calibration of the equipment. Nearby the zero degree position, adhesion coefficient between planta and single-layer sand was 0.64 to 0.9, which indicated that the plana of ostrich have a good adhesion property on single-layer sand. On circumferential angle position, adhesion coefficients between planta and 200mm depth sand were measured every other ten degree. Nearby one hundred and eighty degree, the adhesion coefficient was the biggest which was corresponding to the braking of the ostrich. Nearby the zero degree, the adhesion coefficient was the smallest which was corresponding to the walking or running in a straight way of ostrich. On other parts of the circumferential, the adhesion coefficients were between the one hundred and eighty degree and zero degree, which corresponded to the veer of ostrich. One hundred and eight degree position would be a reference in later bionic design. We hypothesized that the papillae can increa the
adhesion property on sand. Some tests showed that the papillae can increa the adhesion property notably.
3D scanner was ud to obtain the curved surface of the planta. Geomagic Studio and CATIA were
ud to deal with 3D data to gain a curve. Bad on the curve and former test data, bionic surface of wheel on sand environment was designed with convex body. Simulations, which was done by EDEM, were ud to find the best size of the convex body. At last, we gain the biggest adhesion force when the size of the convex body and the height of them were 2mm. Bad on the best size of convex body, bionic surface and normal surface of wheel were manufactured. Tho surfaces were ud to do some tests which called forward direction pulling plate test and rever direction pulling plate test. Test data showed that the adhesion property of bionic surface was better than normal surface. Test data also showed that only the bionic surface cooperated with convex body can achieve good effect. Arrayed the surface to be a whole wheel 3D model. Imported the 3D model to EDEM to do some simulation. The results showed that thrust force of bionic wheel was 113.4% larger than normal wheel. Bionic rearch in surface of wheel on sand environment can afford new thinkings and design references for improving traveling ability of wheel on sand enviroment.
数学速算方法>成都的歌词Key words:
planta of ostrich, papilla, adhesion property, surface of traveling-sand wheel, bionic design, numerical simulation.
目录
第1章绪论 (1)
1.1 研究的背景及意义 (1)
1.2 越沙轮面研究现状 (2)
霸气昵称男生
1.3 仿生学在越沙轮面和机构上的应用 (7)
1.4 鸵鸟及其工程仿生研究现状 (9)
1.4.1 鸵鸟及其优异性能 (9)
1.4.2 鸵鸟足的仿生研究现状 (10)
1.5 本研究的主要内容 (13)
1.6 本章小结 (14)
第2章鸵鸟足底乳突形貌及尺度测试与分析 (15)
2.1 乳突群的宏微观分析 (15)
2.1.1 试验材料准备 (15)鄙意
三个代表本质2.1.2 试验过程 (16)
2.1.3 试验结果 (16)
2.2 乳突的力学特性测试 (21)
2.3 鸵鸟足底乳突尺度的统计分析 (23)榨汁食谱
2.4 乳突的方向分布 (28)
2.5 鸵鸟足侧面附着物形貌与成分分析 (29)
2.6 本章小结 (32)
分布系数
第3章鸵鸟足底附着特性测量装置及试验方法 (33)
3.1 鸵鸟足底附着特性测量装置设计 (33)
3.2 附着特性测量装置的标定 (35)
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