免耕播种机凹面爪式清茬机构仿真与试验

发布时间：2018-06-07 05:41

本文选题：保护性耕作 + 秸秆还田　；参考：《吉林大学》2017年硕士论文

【摘要】：保护性耕作技术可以保护生态环境、降低农作物生产成本,能有效实现农业可持续发展。我国形成了以“地表覆盖、少耕免耕、联合作业”为关键技术的保护性耕作体系,通过联合作业、蓄水保墒、培肥地力,实现农业可持续发展。免耕播种机是保护性耕作的重要装备之一,不同地区的作物种类、作业环境以及农艺要求各不相同,研发设计适用于不同地区的免耕播种机非常重要。种床清理是影响免耕播种机作业效果的重要条件,因此免耕播种机种床清理机构至关重要,本文针对东北地区玉米保护性耕作模式,根据免耕播种机清茬机构的技术要求以及圆盘耙片的运动曲线,设计了一种具有凹面爪式结构的种床清理机构。本文所设计的凹面爪式清茬机构在免耕播种机的牵引下与土壤产生了相互作用力,在土壤的反力作用下使得轮爪转动,作业的轮爪捡拾并翻抛秸秆,达到清理种床的目的。通过理论分析确定清茬机构主要结构参数:凹面圆盘曲率半径为1346 mm、凹面圆盘直径为320 mm、清茬轮轮爪数量为12。通过运动学和动力学分析得出影响清茬机构的种床清理能力的主要因素为:免耕播种机的作业速度、清茬轮触土深度以及清茬轮运动偏角。对传统平面清茬机构与凹面爪式清茬机构进行了对比试验,在同一因素水平下,分析对比了同一结构参数的平面清茬机构和凹面清茬机构的清茬率以及其它参考试验指标,得出本文所设计的凹面清茬机构清茬效果高于平面清茬机构、所受秸秆和土壤总力低于平面清茬机构。本文采用仿真分析与田间试验相结合的试验手段,保证了试验结果的可靠性。建立秸秆粉碎还田条件下的清茬机构—地面系统模型,仿真分析了清茬机构各因素各水平组合下的作业情况。仿真试验主要试验指标为清茬率,参考试验指标为清茬机构作业时所受来自土壤和秸秆的总力以及秸秆翻抛速度。根据Design-Expert软件中Box-Behnken Design组合设计原理,进行田间正交试验,田间试验指标为清茬率,通过试验数据优化分析得出凹面清茬机构最佳工作参数组合。综合EDEM仿真试验与田间试验得出本文所设计的凹面爪式清茬机构的最佳参数组合为:运动偏角为37.5°、机具速度为2.77 m/s、触土深度为70 mm。本文所设计的凹面爪式清茬机构可有效清理种床、减少秸秆及杂草缠绕、减少机具堵塞、安全性高、能耗小,同时适用于我国玉米均匀垄耕作模式和玉米宽窄行作业模式。本文所设计的凹面爪式清茬机构具有一定的结构创新性,对凹面爪式清茬机构主要试验指标清茬率和其它参考试验指标试验分析的结论,为秸秆还田条件下的种床清理机构提供了研究基础;所建立的EDEM仿真模型对秸秆还田条件下的清茬机构的仿真分析具参考价值。
[Abstract]:Conservation tillage technology can protect the ecological environment, reduce the production cost of crops, and realize the sustainable development of agriculture effectively. China has formed a conservation tillage system with "surface cover, less tillage and no-tillage, combined operation" as the key technology. Through the combined operation, the soil moisture is stored and the soil fertility is increased, so as to realize the sustainable development of agriculture. The no-tillage planter is one of the important equipment of conservation tillage. The crop types, working environment and agronomic requirements are different in different areas. It is very important to develop and design no-tillage planter suitable for different areas. Seed bed cleaning is an important condition that affects the operation effect of no-tillage planter, so the cleaning mechanism of no-tillage planter seed bed is very important. According to the technical requirements of stubble cleaning mechanism of no-tillage planter and the movement curve of disc rake a kind of seed bed cleaning mechanism with concave claw structure was designed. The concave claw type stubble cleaning mechanism designed in this paper has produced interaction force with soil under the traction of no-tillage planter. Under the action of soil reaction, the wheel claw rotates and the working wheel claw picks up and flips the straw, so as to clean up the seed bed. The main structural parameters of stubble cleaning mechanism are determined by theoretical analysis: the curvature radius of concave disc is 1346 mm, the diameter of concave disc is 320 mm, and the number of stubble wheel claw is 12.2 mm. Through kinematics and dynamics analysis, the main factors affecting the cleaning ability of the seed bed of the stubble cleaning mechanism are as follows: the operating speed of the no-tillage planter, the depth of soil contact of the stubble wheel and the angle of movement of the stubble wheel. The conventional plane stubble cleaning mechanism and concave claw stubble cleaning mechanism are compared. Under the same factor level, the stubble removal rate of plane stubble cleaning mechanism and concave stubble cleaning mechanism with the same structural parameters and other reference test indexes are analyzed and compared. It is concluded that the stubble cleaning effect of concave stubble cleaning mechanism is higher than that of plane stubble cleaning mechanism, and the total force of straw and soil is lower than that of plane stubble cleaning mechanism. In this paper, the reliability of the test results is ensured by the combination of simulation analysis and field experiments. The ground system model of stubble mechanism under the condition of straw comminuting and returning to field was established, and the operation situation was simulated and analyzed under each level combination of various factors of stubble mechanism. The main test index of simulation test is stubble rate, and the reference index is the total force from soil and straw and the rotation rate of straw. According to the principle of Box-Behnken Design combination design in Design-Expert software, the field orthogonal experiment was carried out, and the field experiment index was stubble cleaning rate. The optimum working parameters combination of concave stubble cleaning mechanism was obtained by optimizing analysis of test data. The optimum parameters of the concave claw stubble cleaning mechanism designed in this paper are as follows: the angle of motion is 37.5 掳, the speed of the machine is 2.77 m / s, and the depth of touching soil is 70 mm. The concave claw type stubble cleaning mechanism designed in this paper can effectively clean up the seed bed, reduce the winding of straw and weeds, reduce the clogging of machinery and tools, have high safety and low energy consumption. It is also suitable for maize uniform ridge tillage and wide and narrow row operation in China. The concave claw type stubble cleaning mechanism designed in this paper has certain structural innovation. The conclusion of the experiment analysis on the main test indexes of concave claw stubble cleaning mechanism and other reference test indexes is concluded. It provides the research foundation for the seed bed cleaning mechanism under the condition of straw returning to the field, and the EDEM simulation model established has reference value for the simulation analysis of the stubble cleaning mechanism under the condition of straw returning to the field.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S223.2

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