【作者】 金鑫；

【导师】 李树君； 李栋；

【作者基本信息】 中国农业大学 ， 农业机械化工程， 2014， 博士

【摘要】 移栽技术在蔬菜种植中具有高产稳产、提高土地利用率等诸多优越性。全自动机械化移栽技术能够提高作业效率、降低人工喂苗劳动强度、提高综合经济效益,是蔬菜移栽机械的发展趋势。本文以番茄穴盘苗自动移栽的关键技术与装置为研究对象,在穴盘苗钵体力学性能试验研究的基础上,通过对取苗机构的理论研究与仿真分析,开发了蔬菜穴盘苗自动识别取苗系统,并进行了系统的作业性能检测试验。得到如下结论：1.在番茄穴盘苗苗龄期40天,以基质成份体积比、含水率和位移为试验因素,对苗钵抗压性能、蠕变特性和取苗拉拔力进行了试验研究。结果表明：基质成份FNZ(即泥炭和珍珠岩体积比=2：1)、含水率55%时,苗钵抗压能力最强,最大抗压力4.70N、压缩位移13.45mm、取苗所需拉拔力2.67N,最适宜机械取苗作业；含水率55%、受压力5N持续2s的条件下,不同基质成份的苗钵蠕变量均小于0.04mm,对快速夹取钵体的夹紧松弛特性影响可忽略不计；取苗拉拔力受试验因素影响较小,基本在2-3N范围内变化。2.提出了“啄木鸟”式取苗轨迹,建立了符合该轨迹要求的五杆-定轴轮系组合式取苗机构理论研究模型,并基于VB.NET开发了计算机辅助分析与优化软件,分析了模型参数变化对机构取苗轨迹和振动的影响,优化得到l1=29mm、l2=90mm、l3=93mm、l4=42mm、l5=180mm、l6=126mm、 xD=74mm、yD=27mm、α10=169°、α40=319°、θ1=165°、θ2=90°,为机构最佳参数组合,通过Inventor三维建模仿真分析,得到此组合下机构取苗轨迹高度239.7mm,入穴取苗段轨迹直线段长度31.2mm,入穴取苗、拔苗段轨迹与穴盘面几乎垂直(为88.2°),验证了理论模型的正确性,并得出取苗频率60株/min-90株/min时机构作业性能较好。3.开发了自动识别取苗系统,系统由五杆-定轴轮系组合式取苗机构、供苗机构、秧苗识别传感器及控制系统组成。取苗机构结构参数依据理论模型确定,采用两夹苗指针取苗,夹持苗钵压缩量8mm、入穴取苗两指针夹苗角度16.4°、夹持力4.21N、拉拔力5.31N；供苗机构能够横纵向交替间歇式移盘；采用基于背景抑制漫反射式光电传感器苗茎检测方案和基于PLC的控制系统,实现蔬菜穴盘苗自动准确、高效取苗并减少穴盘缺苗引起的漏栽；系统针对苗茎进行识别,位置约为距离苗盘面15mm、检测距离35mm,在横、纵向供苗过程依靠传感器触发识别穴格有无苗,指导供苗机构动作完成穴盘苗取、供配合作业,取苗频率最高可达到90株/min。4.利用自动移栽试验装置完成了自动识别取苗系统的作业性能检测试验。试验结果表明：自动识别取苗系统不仅实现了蔬菜穴盘苗的自动准确、高效取苗,同时基本满足识别取苗要求;当移栽频率60株/min和90株/min时,取苗成功率分别为92.41%和86.48%;漏栽率较未采用识别取苗整体降低约12%,减少了因穴盘缺苗而导致的漏栽。更多还原

【Abstract】 Transplanting technique has lots of advantages at vegetable cultivation, such as enhance the high and stable yield, and improving the land utilization rate. Automatic transplanter is a most important trends at vegetable transplanting technology, which can promote work efficiency, reduce human-dependent seedlings feeding labor intensity and increase economic benefit. The object of this research were to aim at the key technology and equipment of tomato plug seedlings transplanting, experimental investigate the mechanical properties of plug seedlings, theoretical study and simulation the plug seedlings pick-up mechanism, develop and verify an automatic recognition picking vegetable plug seedlings system. Conclusion was as follows,1. The tomato seedlings at40days period were investigated through compressive capacity, creep strain and pullout force testing s base on the factors of morphological characteristics, physical dynamics, and pullout strength. The results showed the best tomato seedlings for the picking seedlings machinery was FNZ substrates (peat/perlite was2:1by volume) at55%moisture content, meanwhile the compressible displacement of seedling pot was13.45mm. When substrates at55%moisture content, the creep strain of seedling pots was pretty small after5N pressure sustaining2s, and the influence of clamping relaxation properties could be neglected while quickly mechanical picking plug seedling. The pullout force was2N-3N, and little affected by experimental factors.2. A woodpecker type trajectory of picking seedlings was invention, and a theory model of the five-rod fixed axis gear train combined type plug seedlings pick-up mechanism, which can meet the requirements of picking seedlings trajectory. Then, the computer aided analysis and optimization software of the theory model was developed based on software VB.NET, and the influence law of seedlings pick-up trajectory and mechanism vibration affected by the model parameters was obtained. The optimal parameters combination was l1=29mm, l2=90mm,l3=93mm,l4=42mm,l5=180mm, l6=126mm, xD=74mm,.yD=27mm, α10=169°,玖40=319°,θ1=165°,θ2=90°. Simulated analysis of the mechanism3-D model by software Inventor at the optimal parameters combination showed that the height of seedlings pick-up trajectory was239.7mm, the length of seedlings pick-up trajectory in pot was31.2mm, the angle between seedlings pick-up trajectory in pot and seedlings pot surface was almost vertical. So the correctness of the theory model was verified, and the conditions of the good operation performance of seedlings pick-up mechanism was obtained that the picking seedlings frequency was60strains per minute to90strains per minute.3. An automatic recognition picking plug seedlings system was developed which consisted of five-rod fixed axis gear train combined type plug seedlings pick-up mechanism, seedlings feed mechanism, identification sensor of plug seedlings and control system. The seedlings pick-up mechanism parameters were based on theoretical model, using two fingers picking seedlings, and the amount of compression for holding seedlings pot was8mm, the angle of two fingers on plug seedlings pick-up mechanism for clamping seedlings pot was16.4°, the holding force was4.21N, the picking force was5.31N. The plug seedlings could be alternately intermittently fed vertically and horizontally by seedlings feed mechanism. The system was based on background suppression reflected photoelectric sensor and PLC program control to continuously automatically recognizing, picking and feeding the plug seedlings. The system could recognize seedlings stem, and the recognition position was15mm height of seedlings stem, the recognition distance was35mm between the seedlings stem. During the process of feeding seedlings, the identification sensor conducted recognizing plug seedlings in trays. The highest frequency of picking seedlings of the system was90strains per minute.4. To verify the work performance of the automatic system, a test device of automatic transplanting vegetable plug seedlings was built. The verify experiment result showed that the automatic recognition picking plug seedlings system could automatic, accurate and high efficient recognize the seedling in tray that satisfy recognition picking plug seedlings requirements. When the transplanting frequency were60strains per minute and90strains per minute, the success rate of the seedlings pick-up were92.59%and87.41%respectively, and the decreased leakage transplanting rate was about12%compare to the transplanter without the automatically picking seedlings control system. The success rate of seedlings pick-up was92.59%as the transplanting frequency at sixty strains per minute, and87.41%as the transplanting frequency at ninety strains per minute. The leakage transplanting rate with automatically recognition picking seedlings control system was12%lower than without the automatically recognition picking seedlings control system.更多还原