【作者】 李常营；

【导师】 贾洪雷；

【作者基本信息】 吉林大学 ， 农业机械化工程， 2014， 博士

【摘要】 随着普通耕作方式和秸秆焚烧带来的土地流失加剧、土壤肥力不断下降、空气雾霾污染加重，人们逐渐意识到保护耕地、保护环境的重要性和紧迫性。针对农作物秸秆作为废弃物或者直接在田间焚烧带来的资源浪费和土壤环境污染，人们对秸秆的处理及利用方式提出了很多建议。保护性耕作以保护耕地为主要目标，并能实现农作物稳产高产且可持续发展的一种先进的农业耕作技术，越来越得到人们的重视，重要的是其对秸秆的还田处理得到了人们的广泛认可，因此在越来越多的国家和地区均积极推行保护性耕作。保护性耕作的内涵除了免耕少耕之外还包括秸秆还田，人们普遍认为秸秆还田能有效增加土壤有机质含量，疏松土壤并能增加土壤蓄水保墒的能力，并且具有促进农作物增收的作用。而且将秸秆进行覆盖还田还有明显的防风固土的作用，能有效减缓土壤水蚀和风蚀现象。但是，农作物秸秆也是重要的生物质能源，在不可再生资源日益枯竭的情况下，生物质能源越来越受到人们的重视。随着秸秆的综合利用技术越来越成熟，越来越多的秸秆将被综合利用，而不能简单全部进行还田，特别是东北地区，寒冷的天气很难保证秸秆有效的腐烂进行有机质还田。同时，为了满足保护性耕作对秸秆还田的农艺要求，秸秆应该一部分进行综合利用，另外部分秸秆进行还田。在此基础上，推广留高茬覆盖还田的保护性耕作模式是合适的。由此可知，针对东北地区收获玉米时较为合理的农艺是：在玉米收获的同时对玉米秸秆进行留高茬切割，留高茬作业（留茬高度为300~500mm）满足保护性耕作秸秆还田的要求，同时将切割下的秸秆进行收集打捆作业，然后进行秸秆的综合利用。因此，秸秆的切割是秸秆还田和秸秆进行综合利用之前必须完成的作业。目前，玉米收获机在收获时主要是将玉米秸秆全部粉碎或者不处理，还没有能够留高茬作业的机型。由此，本文研究重点放在了玉米收获机的留高茬作业切割部件设计上，尤其针对切割使用的锯片进行了仿生设计。（1）本文设计了能够自动留高茬的玉米联合收获机切割机构，该机构采用圆盘回转式切割，切割装置的动力来源为发动机动力输出轴，发动机动力输出轴的动力经传动箱和链轮传递到切割装置上。通过自制夹持玉米秸秆的装置进行了切割试验，结果表明该留高茬切割装置设计合理，能够达到留高茬的设计要求。（2）本文作者对切割机构的切割部件进行了仿生设计。自然界中，切割现象是非常普遍的，很多动物或者昆虫将食物撕裂或者切断（咬断）都属于切割的范畴，如以蛀食打洞危害的蠹虫、啮齿类的老鼠甚至吃植物叶茎的昆虫等。而以植物为主食的昆虫类，棉蝗是典型的代表，经过漫长的进化历程其具有优良的进食口器（咀嚼式口器），可以有效地取食植物的茎叶。通过观察发现棉蝗在进食时可以有效的切断食物。因此，本文作者对棉蝗的口器进行了观察，尤其对具有切割功能的上颚切齿叶部分进行了深入研究。将棉蝗上颚样品在体式显微镜下拍照观察，将拍到的照片用Matlab软件进行处理并提取出上颚切齿叶的外轮廓点的坐标，通过Origin软件进行曲线拟合，将该轮廓切齿叶部分拟合成5段曲线，以该拟合后的曲线为原型进行切割部件的仿生设计。（3）基于仿生原型先后设计了直线型和圆盘型2种类型的仿生切割部件，并以普通锯齿的锯条和锯片为对照进行了玉米秸秆的切割试验。对于直线型的仿生锯齿锯条，以万能试验机为动力拉动直线型仿生锯齿锯条切割固定的玉米秸秆，在空间直角坐标系中将直线型锯条放置在YOZ平面且与Z轴成12度夹角固定在夹具中与万能试验机横梁相连，玉米秸秆在XOZ平面水平放置并固定在自制的夹具中与万能试验机基座相连。直线型锯条以2mm/s的速度从秸秆下方向上运动切割玉米秸秆，通过计算机软件实时记录了切割过程的切割力的大小变化和锯条的位移，切割试验独立重复12次。通过和普通锯齿锯条的对比，结果表明仿生锯齿锯条有显著的降低切割力的作用（P <0.05），普通锯齿锯条切割一根玉米秸秆的平均切割力为71.78N，而仿生锯齿锯条的平均切割力为51.56N，降低了28.17%。相对于普通锯齿锯条，仿生锯齿锯条切割一根玉米秸秆所消耗的能量从10.27J降低为8.95J。通过视频慢放可以看出普通锯齿锯条切割玉米秸秆时主要是齿尖钩住一部分玉米秸秆，随着锯条的持续拉动，剥离秸秆后逐渐被拉断，而仿生锯齿锯条切割时除了拉断之外主要是靠切齿的滑切作用切断秸秆。（4）对于圆盘型的仿生锯齿锯片，由于不能使用万能试验机进行试验，本文作者设计了玉米秸秆切割试验台。该试验台通过电动机带动圆盘锯片进行秸秆的切割试验，通过扭矩传感器测量切割过程中的锯片切割扭矩变化，通过调节皮带轮的传动比改变圆盘锯片的切割速度，通过直流电机改变玉米秸秆的运动速度，通过拉力传感器测定切割过程的拉动玉米秸秆的拉力，并通过动态信号采集分析系统进行数据采集处理。试验考察了圆盘锯片的切割速度、玉米秸秆的前进速度、切割倾角3个因素对切割力、切割功耗、秸秆拉力和切割时间等的影响。试验进行了全因素试验，每个试验独立重复3次，试验表明：各因素对切割扭矩、切割功率及切割功耗均有显著性的影响（P <0.05）。在切割转速为600rpm、切割倾角为75°、秸秆牵引速度为1.3m/s的条件下，仿生锯齿锯片和普通锯齿锯片进行了切割玉米秸秆的对比试验，试验独立重复20次。结果表明仿生锯齿锯片和普通锯齿锯片均可以实现有效切割，普通锯齿锯片切割玉米秸秆的平均切割扭矩为1.691±0.226N·m，而使用齿尖采用交错双面磨刃的仿生锯齿锯片B切割玉米秸秆时的平均切割扭矩为1.439±0.214N·m，相对于普通锯齿锯片的切割降低了14.89%。普通锯齿锯片切割玉米秸秆消耗的能量为34.034±5.224J，而使用齿尖采用交错双面磨刃的仿生锯齿锯片B切割玉米秸秆有明显的降低能耗的作用，切割所需的能耗为27.741±6.181J，降低了18.49%，而切割时间没有显著性的变化。同时通过高速摄像进行切割过程观察，结果表明仿生锯齿锯片切割产生的碎屑较少使切割平面更为平整。（5）将圆盘型仿生锯齿锯片装置装到玉米收获机留高茬切割机构上，于2013年秋季在吉林大学农田试验场进行了田间收获和秸秆切割试验。试验结果表明：圆盘型仿生锯齿锯片能有效的切割玉米秸秆，无推倒现象发生，相对于普通锯齿锯片，具有留茬整齐的特点。在试验过程中没有发现拥堵的现象，对收获质量没有不良影响，证实了该留茬机构设计合理，同时能够满足保护性耕作留高茬的要求。田间试验结果表明玉米秸秆留茬的高度为399.5±24.9mm，在300~500mm之间，合格率为100%，由于受田间地块地貌及秸秆自然倒伏的影响，秸秆的切断率为93%。本文的研究内容来源于生产实际中遇到的问题，即玉米收获机收获玉米时如何实现留高茬，作者在原有的机型上设计了留高茬切割机构，通过试验证实了其合理性，同时运用仿生的方法进行了切割部件的仿生设计，玉米秸秆的切割试验表明仿生切割部件具有降低切割功耗的作用。因此，本文的研究内容在推广保护性耕作方面有一定的促进作用，另外仿生切割部件的设计在节能减排方面有重要的意义，为以后的切割部件的设计提供了参考。更多还原

【Abstract】 With conventional tillage and straw burning caused soil erosion increasing,declining soil fertility, increased air pollution haze, people gradually realized that theimportance and urgency of protecting arable land and environment. Straw as waste ordirectly burn up brings waste of resources and environmental pollution of soil, andmany suggestions to deal with straw were bring up. Meanwhile conservation tillage asan advanced farming technology mainly to protect arable land as the main objective,and to achieve high-yield crops and sustainable development, obtained more and morepeople’s attention, that important for straw back to field has been widely recognized bythe people, therefore more and more countries and regions are actively promotingconservation tillage. In addition to the connotation of conservation tillage for no-tillageand less-tillage, also includes straw back to field, it is widely believed straw caneffectively increase soil organic matter content, loose soil and can increase the capacityof the soil moisture conservation, and promote the crop yield. And the straw mulchingsolid earth could protect against wind, and effectively reduce soil water and winderosion phenomenon. However, crop stalks are also important sources of biomass, inthe case of non-renewable resources are depleted, and biomass energy obtained moreand more people’s attention. With the utilization technology of straw developed, moreand more utilization of straw will be used, but we cannot simply all be returning to thefield, especially in the Northeast, the cold weather is difficult to ensure effective stalkrotting increasing organic matter in field. Meanwhile, in order to meet conservationtillage on straw agronomic requirements, the paper advocates comprehensive utilizationof partial stalk, the other was put back to field. On this basis, the promotion of highstubble mulching conservation tillage mode is appropriate.It can be seen, when harvesting corn Northeast a more reasonable process is: whilethe corn harvest corn straw stubble cutting, leaving high stubble (stubble height of300~500mm) to meet conservation tillage straw requirements, while cutting down thestraw which would be bale collected, then utilization. So cutting the stalks must becompleted before the straw back to field and straw utilization operations. Currently, corn harvester mainly to smash all the corn stalks at harvest or no treatment, has notbeen able to stay high stubble operating models. Thus, this paper focused on the stubblecutting operating components of corn harvester, especially for the cutting blade carriedout using bionic design.（1）In a basis of the existing laboratory type4YZB-2corn combine harvester,removed the straw chopper off the device and designed the cutting stalk componentsunder snapping rolls. The cutting part uses the rotary disc cutting apparatus for cutting,the power source output shaft of the engine power, the power of the engine through thetransmission box and the power output shaft of the sprocket is transmitted to the cuttingdevice. Through self-made gripping device corn stalks were cut, results showed thatthe stubble cutting device reasonably designed to achieve high stubble designrequirements.（2）Atthesametimepartofthecuttingmechanismforcuttingwerebionicdesign.Nature, cutting phenomenon is very common, many animals or insects will tear or cutfood (biting) are all cutting areas, such as to endanger the silverfish eats holes, evenrodents mice and insects eat the leaf and stems. The plant-eating insects, especially thefamous locust plague of locusts is represented through a long evolutionary history ofits excellent eating mouthparts (chewing) can effectively feeding on stems and leavesof plants. The observation that when eating locusts can effectively cut off food.Therefore, mouthparts of locusts were observed, especially for the upper jaw with teethcut function. The locust’s palate samples observed under stereo microscope camera andtake photos with Matlab software for processing to extract the coordinates of the upperincisors, and the outer contour points by curve fitting software Origin, fitting into fivesegments curve. The fitting curve is the prototype of the bionic design cutting parts.（3）Based on the prototype linear and disc type bionic cut parts were designed,and traditional serrated blade as control, corn stalks were cut test.For linear bionic serrated blade, universal testing machine as the power to pullstraight serrated blade cutting fixed corn stalks, in the space of a Cartesian coordinatesystem in place at YOZ straight blade angle between the plane and the Z axis12degreesfixed in the fixture beams connected with universal testing machine, corn stalks in ahorizontal plane and fixed XOZ connected with the universal testing machine base inhomemade fixture. Straight blade speed of2mm/s cutting corn stalk from the bottomupward movement, in real time via computer software recorded the cutting force andthe displacement of saw blade, cutting test independently repeated12times.By contrast to conventional serrated blade, results showed bionic serrated blade significantly decrease the cutting force (P <0.05), using conventional serrated cuttingblade cutting corn stalks average force of71.78N, and the average cutting bionicserrated blade force of51.56N,28.17%cutting force was removed. Bionic serratedblade could reduce power consumption, compared with conventional serrated blade,bionic serrated blade cutting a stalk of corn consumed from10.27J reduced to8.95J.But for bionic serrated cutting blade, the cutting time is longer compared toconventional serrated blade, the average cutting time extended from37.52s to43.47s,17.83%extended cutting time.Through the slow motion video can be seen traditional serrated blade when cuttingcorn stalks are mainly part of the tooth tip hooked corn stalks, with the continuedpulling the blade gradually pulled straw after stripping off until cut off. Bionic serratedblade while cutting in addition to pull off the role mainly by sliding cut.（4）For disk bionic serrated blade, because it isn’t work using universal testingmachine to test, the author designed the corn stalk cutting test bench. The test rig drivenby an electric motor test disc blade for cutting corn stalk, the process of cutting bladecutting through the torque sensor to measure torque variation, by adjusting pulley gearratio change disc blade cutting speed, change of corn pulling velocity by continuouscurrent motor and measured the pull force by pulling the sensor, and data acquisitionand processing through dynamic signal acquisition and analysis system. Experimentalstudy of the circular saw blade cutting speed, corn stalks forward speed, and cuttingangle affecting the cutting force, cutting power, pulling force and cutting stalks of time.A full factorial experimental trials was conducted, each test was repeated three times,the test showed that the cutting time is not significantly different，the cutting torqueand the cutting power consumed have significant effects (P <0.05).Cutting speed is600rpm, cutting angle is75°, stalk pulling speed under1.3m/sconditions, bionic serrated blade and traditional serrated blade were used for cuttingcorn stalks comparative test, the test is repeated20times independently. The resultsshowed that the bionic serrated blade and traditional serrated blade can be achievedgeneral effective cutting, using traditional blade cutting corn stalks the mean cuttingtorque is1.691±0.226N·m, while the use of sharp teeth staggered double-sidedsharpening bionic serrated blade B cutting average cut corn stalks when torque is1.439±0.214N·m, relative to the traditional serrated blade cuts reduced14.89%.Traditionalblade cutting energy consumption of corn stalks is34.034±5.224J, use sharp teethstaggered double-sided sharpening bionic serrated blade B cutting corn stalkssignificantly reduce the energy consumption to27.741±6.181J,18.49%lower, and the cutting time is not significantly changed. While cutting through the high-speed camerato observe the process, the results showed that the debris generated by bionic serratedblade cutting corn stalk is less than traditional blade, which indicated the cutting planeis more flat.（5）Placetheserratedbladedisc bionicdevicetothecornharvest stubblecuttingmechanism, in the fall of2013at Jilin University, conducted a field test corn harvestingand cutting stalk tests. The test results showed that: Bionic serrated blade disc caneffectively cut corn stalks, no push over corn stalk phenomenon, as opposed to thetraditional serrated blade, with a stubble neat features. During the test no congestionphenomenon was found, no adverse effects on the quality of the harvest, stubble leavingparts confirmed the rational design of the original system does not have a negativeimpact on the harvest, and to meet the requirements of conservation tillage to remainhigh stubble. Field test results showed that the corn stalk stubble height of399.5±24.9mm, between300~500mm, with a pass rate of100%, due to the topography andnatural straw lodging affect, stalks cut ratio was93%.we try to solve the problem which come from actual production, namely, how toleave high stubble for corn harvester when harvesting corn, and designed the cuttingstalk components which was believed reasonableness. While the use of biomimeticapproach to the design of the bionic cut parts, cutting corn stalks tests showed bionicparts have reduced the cutting power consumption. Therefore, the research content ofthis paper are in terms of the promotion of conservation tillage, in addition to cuttingparts bionic design has important implications in terms of energy saving for the futuredesign of the cutting unit provides a reference.更多还原