【摘要】：甜菜是制糖工業(yè)中僅次于甘蔗的重要糖料來源。甜菜露出土壤外的青頂中含有較多的氮元素，對制糖工藝產(chǎn)生有害的影響，因此切頂是甜菜收獲過程中的重要環(huán)節(jié)。甜菜切頂機(jī)構(gòu)是甜菜收獲機(jī)的關(guān)鍵部件，其性能好壞直接影響甜菜收獲質(zhì)量�，F(xiàn)有的甜菜切頂機(jī)構(gòu)不能在收獲機(jī)作業(yè)過程中調(diào)節(jié)青頂?shù)那懈詈穸�，易出現(xiàn)大甜菜少切、小甜菜多切現(xiàn)象，導(dǎo)致甜菜切頂不能滿足制糖工藝要求，且造成甜菜資源浪費，減少種植戶收益。為此，本文提出一種新型切割厚度可調(diào)甜菜切頂機(jī)構(gòu)，在對其工作機(jī)理進(jìn)行分析的基礎(chǔ)上，優(yōu)化了機(jī)構(gòu)參數(shù)，并通過ADAMS虛擬樣機(jī)進(jìn)行了仿真試驗。研究結(jié)果對研制具有自主知識產(chǎn)權(quán)的甜菜收獲機(jī)、提高我國甜菜收獲的機(jī)械化水平具有一定的理論價值和現(xiàn)實意義。 本文的主要研究內(nèi)容和結(jié)果如下： 1）分析了切割厚度可調(diào)甜菜切頂機(jī)構(gòu)切割厚度調(diào)節(jié)的工作機(jī)理，建立了切頂機(jī)構(gòu)的運動學(xué)模型；根據(jù)甜菜實物建立了甜菜青頂輪廓的數(shù)學(xué)模型。 2）為減少切割阻力，降低機(jī)器能耗，基于滑切和削切原理提出一種切刀調(diào)節(jié)機(jī)構(gòu)，建立了該機(jī)構(gòu)的運動學(xué)模型，并基于VB軟件通過編程分析其運動特性。 3）基于VB6.0編寫了切割厚度可調(diào)甜菜切頂機(jī)構(gòu)的運動學(xué)計算機(jī)輔助分析與優(yōu)化仿真軟件，分析甜菜切頂機(jī)構(gòu)各參數(shù)對切頂軌跡及切割厚度的影響；針對切割厚度可調(diào)甜菜切頂機(jī)構(gòu)參數(shù)優(yōu)化的目標(biāo)，利用該軟件的人機(jī)交互功能，尋求到切頂機(jī)構(gòu)的一組較優(yōu)參數(shù)：機(jī)架離地高度H=570mm，厚度調(diào)節(jié)鏈輪傳動比k=1/2.4，仿形輪節(jié)圓半徑Rf=180mm，齒輪節(jié)圓半徑Rc=100mm，擺臂長度L1=520mm，使大小甜菜青頂均能得到合理的切割。 4）為避免仿形輪在運動過程中打滑或仿形失真，建立了仿形輪速度與牽引速度比值的優(yōu)化模型，利用Matlab軟件基于遺傳算法對仿形輪線速度v和甜菜切頂機(jī)構(gòu)的牽引速度v1及其比值進(jìn)行優(yōu)化，優(yōu)化結(jié)果為：仿形輪線速度為v0.8984m/s，，機(jī)構(gòu)牽引速度為v10.6134m/s，二者比值為v/v11.46，優(yōu)化結(jié)果精確于經(jīng)驗值。 5）利用優(yōu)化所得的各機(jī)構(gòu)參數(shù)，基于UG三維設(shè)計軟件建立切割厚度可調(diào)甜菜切頂機(jī)構(gòu)各零件的實體模型，并對其進(jìn)行虛擬裝配；運用機(jī)械系統(tǒng)仿真軟件ADAMS建立切割厚度可調(diào)甜菜切頂機(jī)構(gòu)的虛擬樣機(jī)模型，進(jìn)行運動學(xué)仿真，得到切刀的切頂軌跡曲線和甜菜青頂?shù)那懈詈穸�；虛擬樣機(jī)的仿真結(jié)果和理論分析結(jié)果基本一致，驗證了理論分析和仿真模型的正確性。
[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.
【學(xué)位授予單位】：浙江理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：S225.72

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本文編號：2130939