切割厚度可调甜菜切顶机构的机理分析与优化设计
发布时间：2018-07-17 21:08
【摘要】：甜菜是制糖工业中仅次于甘蔗的重要糖料来源。甜菜露出土壤外的青顶中含有较多的氮元素，对制糖工艺产生有害的影响，因此切顶是甜菜收获过程中的重要环节。甜菜切顶机构是甜菜收获机的关键部件，其性能好坏直接影响甜菜收获质量。现有的甜菜切顶机构不能在收获机作业过程中调节青顶的切割厚度，易出现大甜菜少切、小甜菜多切现象，导致甜菜切顶不能满足制糖工艺要求，且造成甜菜资源浪费，减少种植户收益。为此，本文提出一种新型切割厚度可调甜菜切顶机构，在对其工作机理进行分析的基础上，优化了机构参数，并通过ADAMS虚拟样机进行了仿真试验。研究结果对研制具有自主知识产权的甜菜收获机、提高我国甜菜收获的机械化水平具有一定的理论价值和现实意义。 本文的主要研究内容和结果如下： 1）分析了切割厚度可调甜菜切顶机构切割厚度调节的工作机理，建立了切顶机构的运动学模型；根据甜菜实物建立了甜菜青顶轮廓的数学模型。 2）为减少切割阻力，降低机器能耗，基于滑切和削切原理提出一种切刀调节机构，建立了该机构的运动学模型，并基于VB软件通过编程分析其运动特性。 3）基于VB6.0编写了切割厚度可调甜菜切顶机构的运动学计算机辅助分析与优化仿真软件，分析甜菜切顶机构各参数对切顶轨迹及切割厚度的影响；针对切割厚度可调甜菜切顶机构参数优化的目标，利用该软件的人机交互功能，寻求到切顶机构的一组较优参数：机架离地高度H=570mm，厚度调节链轮传动比k=1/2.4，仿形轮节圆半径Rf=180mm，齿轮节圆半径Rc=100mm，摆臂长度L1=520mm，使大小甜菜青顶均能得到合理的切割。 4）为避免仿形轮在运动过程中打滑或仿形失真，建立了仿形轮速度与牵引速度比值的优化模型，利用Matlab软件基于遗传算法对仿形轮线速度v和甜菜切顶机构的牵引速度v1及其比值进行优化，优化结果为：仿形轮线速度为v0.8984m/s，，机构牵引速度为v10.6134m/s，二者比值为v/v11.46，优化结果精确于经验值。 5）利用优化所得的各机构参数，基于UG三维设计软件建立切割厚度可调甜菜切顶机构各零件的实体模型，并对其进行虚拟装配；运用机械系统仿真软件ADAMS建立切割厚度可调甜菜切顶机构的虚拟样机模型，进行运动学仿真，得到切刀的切顶轨迹曲线和甜菜青顶的切割厚度；虚拟样机的仿真结果和理论分析结果基本一致，验证了理论分析和仿真模型的正确性。
[Abstract]:Sugar beet is an important source of sugar material in sugar industry after sugar cane. The green top of beet exposed to soil contains more nitrogen elements, which has harmful effect on sugar making process, so cutting top is an important link in the process of sugarbeet harvest. Beet top cutting mechanism is the key component of sugarbeet harvester, and its performance directly affects the quality of sugarbeet harvest. The existing sugarbeet top cutting mechanism can not adjust the cutting thickness of green top in the process of harvester, and it is easy to appear the phenomenon of large beet cutting and small beet cutting, which leads to the sugarbeet top cutting can not meet the requirements of sugar making technology, and causes the waste of sugar beet resources. Reduce the income of growers. In this paper, a new type of beet cutting mechanism with adjustable thickness is proposed. Based on the analysis of its working mechanism, the parameters of the mechanism are optimized, and the simulation experiment is carried out by Adams virtual prototype. The results have certain theoretical value and practical significance for developing sugarbeet harvester with independent intellectual property rights and improving the mechanization level of sugarbeet harvesting in China. The main research contents and results are as follows: 1) the working mechanism of cutting thickness adjustment of adjustable beet top cutting mechanism is analyzed and the kinematics model of top cutting mechanism is established. In order to reduce cutting resistance and reduce machine energy consumption, a cutting tool adjusting mechanism is proposed based on the principle of sliding cutting and cutting, and the kinematics model of the cutting mechanism is established. The kinematics analysis and optimization simulation software of beet cutting mechanism with adjustable cutting thickness was programmed based on VB software. 3) the computer aided kinematics analysis and optimization simulation software was developed based on VB6.0. The influence of the parameters of beet top cutting mechanism on the cutting track and cutting thickness is analyzed, and the man-machine interaction function of the software is used to optimize the parameters of the cutting mechanism with adjustable cutting thickness. A set of optimum parameters of the cutting mechanism were obtained: the height of the rack was 570mm above the ground, the ratio of sprocket drive was adjusted by thickness by 1 / 2. 4, the circle radius of copying wheel was 180 mm, the radius of gear pitch was 100 mm, and the length of pendulum arm was L _ 1 ~ (1) ~ (520mm), so that the green top of beet could be cut reasonably. 4) in order to avoid the slip or distortion of the copying wheel in motion, The optimization model of the ratio of copying wheel speed to traction speed was established. The drawing speed v _ 1 and the ratio of the copying wheel line velocity v and the beet top cutting mechanism were optimized by using Matlab software based on genetic algorithm. The optimized results are as follows: the linear velocity of the copying wheel is v0.8984 m / s, the traction speed of the mechanism is v10.6134 m / s, the ratio of the two is v / v 11.46, and the optimized result is more accurate than the empirical value. 5) using the optimized mechanism parameters, Based on UG 3D design software, the solid model of cutting thickness adjustable beet top cutting mechanism is established and virtual assembly is carried out, and the virtual prototype model of cutting thickness adjustable beet top cutting mechanism is established by using mechanical system simulation software Adams. The kinematics simulation results show that the cutting path curve of the cutting tool and the cutting thickness of the beet green top are obtained, and the simulation results of the virtual prototype are basically consistent with the theoretical analysis results, which verify the correctness of the theoretical analysis and the simulation model.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：S225.72
[Abstract]:Sugar beet is an important source of sugar material in sugar industry after sugar cane. The green top of beet exposed to soil contains more nitrogen elements, which has harmful effect on sugar making process, so cutting top is an important link in the process of sugarbeet harvest. Beet top cutting mechanism is the key component of sugarbeet harvester, and its performance directly affects the quality of sugarbeet harvest. The existing sugarbeet top cutting mechanism can not adjust the cutting thickness of green top in the process of harvester, and it is easy to appear the phenomenon of large beet cutting and small beet cutting, which leads to the sugarbeet top cutting can not meet the requirements of sugar making technology, and causes the waste of sugar beet resources. Reduce the income of growers. In this paper, a new type of beet cutting mechanism with adjustable thickness is proposed. Based on the analysis of its working mechanism, the parameters of the mechanism are optimized, and the simulation experiment is carried out by Adams virtual prototype. The results have certain theoretical value and practical significance for developing sugarbeet harvester with independent intellectual property rights and improving the mechanization level of sugarbeet harvesting in China. The main research contents and results are as follows: 1) the working mechanism of cutting thickness adjustment of adjustable beet top cutting mechanism is analyzed and the kinematics model of top cutting mechanism is established. In order to reduce cutting resistance and reduce machine energy consumption, a cutting tool adjusting mechanism is proposed based on the principle of sliding cutting and cutting, and the kinematics model of the cutting mechanism is established. The kinematics analysis and optimization simulation software of beet cutting mechanism with adjustable cutting thickness was programmed based on VB software. 3) the computer aided kinematics analysis and optimization simulation software was developed based on VB6.0. The influence of the parameters of beet top cutting mechanism on the cutting track and cutting thickness is analyzed, and the man-machine interaction function of the software is used to optimize the parameters of the cutting mechanism with adjustable cutting thickness. A set of optimum parameters of the cutting mechanism were obtained: the height of the rack was 570mm above the ground, the ratio of sprocket drive was adjusted by thickness by 1 / 2. 4, the circle radius of copying wheel was 180 mm, the radius of gear pitch was 100 mm, and the length of pendulum arm was L _ 1 ~ (1) ~ (520mm), so that the green top of beet could be cut reasonably. 4) in order to avoid the slip or distortion of the copying wheel in motion, The optimization model of the ratio of copying wheel speed to traction speed was established. The drawing speed v _ 1 and the ratio of the copying wheel line velocity v and the beet top cutting mechanism were optimized by using Matlab software based on genetic algorithm. The optimized results are as follows: the linear velocity of the copying wheel is v0.8984 m / s, the traction speed of the mechanism is v10.6134 m / s, the ratio of the two is v / v 11.46, and the optimized result is more accurate than the empirical value. 5) using the optimized mechanism parameters, Based on UG 3D design software, the solid model of cutting thickness adjustable beet top cutting mechanism is established and virtual assembly is carried out, and the virtual prototype model of cutting thickness adjustable beet top cutting mechanism is established by using mechanical system simulation software Adams. The kinematics simulation results show that the cutting path curve of the cutting tool and the cutting thickness of the beet green top are obtained, and the simulation results of the virtual prototype are basically consistent with the theoretical analysis results, which verify the correctness of the theoretical analysis and the simulation model.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：S225.72
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