小型智能葉菜類蔬菜收割機(jī)設(shè)計(jì)外文文獻(xiàn)翻譯、中英文翻譯、外文翻譯
小型智能葉菜類蔬菜收割機(jī)設(shè)計(jì)外文文獻(xiàn)翻譯、中英文翻譯、外文翻譯,小型,智能,葉菜類,蔬菜,收割機(jī),設(shè)計(jì),外文,文獻(xiàn),翻譯,中英文
Design of small intelligent vegetable harvester
Gao long, Yijinggang, Kong Degang, Yuan Yongwei
Absrtact: at present, most of the vegetable harvesting in China is basically done manually, the harvesting efficiency is low, and the damage to vegetables is great. Aiming at the problems of leaf vegetable harvesting, a small intelligent automatic leaf vegetable harvester was designed by using function tree to analyze the machine function. The machine can intelligently adjust the cutting width and stubble height of harvested vegetables according to the different kinds of vegetables, and adopt battery DC drive technology, wire rod lifting technology, bidirectional lead screw technology and grading transmission technology. The harvester has high harvesting efficiency, which can ensure the harvesting quality of vegetables and meet the needs of leafy vegetables in most areas of China.
Research on Agricultural Mechanization
[Year (Vol.), Issue ]2016(000)009
[Total pages ]4
[keywords] vegetable harvester; cutting adjustment; stubble adjustment
0 Introduction
According to the latest information :2014, China's vegetable area of more than 20 million hm2, Annual output exceeding t ,700 million For over 500 kg per person, Both ranked first in the world [1]. Among them, Facilities vegetable area up to hm2,3.862 million Leaf vegetables account for 50%[2] of facility vegetables. Because of the ecological characteristics of different leafy vegetables, The unified harvest of leafy vegetables is difficult, Its harvest work basically depends on manual completion; But the growth cycle is short, The quality of harvesting is difficult to control, Directly affect the quality of vegetables, and the value [3] of leaf vegetables is reduced. As labor prices rise, The cost of manual harvesting has increased significantly in the cost of vegetables, A kind of intelligent leaf vegetable harvesting machinery [4] is urgently needed in the market. To that end, Design an intelligent automatic leafy vegetable harvester, Can vary according to vegetable species and harvesting requirements, Intelligent adjustment of cutting amplitude and stubble height, And the key working parts are optimized. This machine makes full use of power resources, To minimize environmental pollution during machine operations, Make it meet the harvesting requirements of leafy vegetables in most areas of China.
1 Device programming
For the purpose of designing the functions of the small intelligent automatic leafy vegetable harvester, the function tree [5] of the harvester is analyzed, and the analysis structure is shown in figure 1
According to the principle of creation method, the functional morphology matrix [6] can be established, as shown in Table 1.
according to the morphological matrix theory, there can be 2×3×3×3,2×3,3=324 schemes to realize the function in the functional tree. Through the analysis of similar products in domestic and foreign markets, comparing the advantages and disadvantages of various execution methods and taking into account the requirements of cost, difficulty and reliability of assembly of small intelligent automatic leafy vegetable harvester, the final scheme is determined as disk drive wheel walking, conveyor belt conveying vegetables, two-way lead screw cutting pair adjustment, wire rod lifting stubble adjustment, disc cutter cutting vegetables, and manual start-stop control scheme.
2 General structure
The blade vegetable harvester uses battery as DC power supply; the front end of the harvester is equipped with stubble height adjustment mechanism, which is composed of DC motor and wire rod lift, which is driven up and down by DC motor; the front end is equipped with cutting adjusting device, which is driven by motor and can be adjusted manually. The stubble adjusting mechanism, the splitter, the cutting amplitude adjusting mechanism, the conveying mechanism, the conveying DC motor, the forward handrail, the control box, the walking wheel and the collection box are all installed on the rack, and the cutting knife driven by the DC motor is arranged on the cutting amplitude adjusting mechanism, as shown in figure 2.
As shown in Fig .2, the DC motor is directly connected with the wire rod hoist, both of which are installed in the front end of the frame; the splitter is installed in the middle of the front end of the frame; the cutting mechanism is installed in the lower part of the frame; the front end of the conveying mechanism is installed in the front end of the cutting mechanism, the middle part is arranged in the middle of the frame, and the rear is installed in the rear end of the frame; the battery is placed in the lower part of the frame; the driving wheel is arranged in the lower part of the battery and connected to the frame; the control box is installed on the right side of the middle of the frame; The vegetable collection box is installed at the rear of the rack, and the forward armrest is connected to the protruding part of the rear of the rack.
When working, the species of harvested vegetables are determined, the signal is sent out by the control box, the amplitude and width adjustment mechanism and the wire rod lift are moved to the appropriate harvesting position, and the two actions stop. At this point, the cutter starts to work, the walking wheel starts to walk under the drive of the DC motor, and the conveying mechanism moves under the drive of the conveying motor. The harvested vegetables are flipped and transported to the secondary conveying device by the first stage conveying device °90.
3. Key component design
3.1 Cutting adjustment mechanism
The cutting adjustment mechanism is composed of the main adjustment mechanism and the fine adjustment mechanism.The main adjustment mechanism mainly includes DC motor, bidirectional lead screw and cutter placement device.The micro adjustment mechanism includes a small two-way lead screw, a handwheel and a width controller, as shown in Figure 3.
The whole adjusting mechanism is installed at the front end of the harvester support; the DC motor is connected with the bidirectional lead screw through the coupling, and the square nut on the bidirectional lead screw is connected with the cutter placement device. When the DC motor rotates, the bidirectional lead screw rotates and drives the square nut to move in a straight line, thus realizing the adjustment of the harvest line spacing. The square nut on the small two-way screw in the fine-tuning mechanism directly fixed the width controller and adjusted the spacing of the width controller by shaking the handwheel on both sides. The main function of the fine-tuning mechanism is to adjust the clamping width of different vegetables manually.
3.2 Cutting height adjustment mechanism
The stubble height adjustment mechanism consists of DC motor, wire rod hoist and walking wheel, as shown in figure 4.
The DC motor is directly connected with the wire rod hoist, the two wire rod elevators are connected by the synchronous shaft, and the walking wheel is installed at the lower end of the wire rod of the wire rod hoist.
The stubble adjusting mechanism determines the stubble height according to the species and growth status of different leafy vegetables. The control device gives the definite signal, the DC motor rotates, drives the wire rod lift to carry on the lifting movement, thus realizes the different kind and the different growth condition vegetable has the different stubble height.
3.3 Transport institutions
The conveying mechanism is composed of the first stage conveying mechanism and the second stage conveying mechanism: the first stage conveying mechanism mainly includes the front end vertical conveying small wheel, the transverse conveying wheel and the strip belt, etc. The second stage conveying mechanism includes the front and rear conveying wheel, the wide conveyor belt, etc. The structure is shown in figure 5.
The first stage conveying mechanism is installed on the front end of the vegetable harvester, one end of the strip belt is installed on the vertical conveying wheel, the other end of the adjacent two belts is placed on the upper and lower two vertical conveying wheels respectively, and the vegetables can be transported by clamping force between the adjacent two belts. The main function of the primary conveying mechanism is to hold and transport the harvested leafy vegetables and the vertical vegetables horizontally and then to the secondary conveying mechanism; The secondary conveying mechanism conveys the vegetables from the primary conveying mechanism to a higher position and throws them into the collection box.
4 Determination of vegetable transport speed
The conveying mechanism is a bridge connecting cutter and collecting box, and its speed directly affects the working performance of the whole machine. The conveying mechanism can not be blocked or waste unnecessary power, and the vegetables should be stored in the collection box. In order to ensure the harvest quality of leafy vegetables, it is necessary to calculate the conveying speed of the conveying mechanism and obtain the conveying speed matching the walking speed of the whole machine.
4.1 Speed calculation of the first stage conveyor mechanism
The first stage conveying mechanism mainly depends on the clamping force of the strip belt to carry on the vegetable transportation, the conveyor belt fast clamps the vegetable layer thin, the conveyor belt slow increases the vegetable layer thickness. At this point, the conveyor belt speed should be determined according to the specified vegetable stacking thickness so that the conveyor belt unit time of vegetable transport and machine harvest equal and [7]. i
VmBq1=Vsdq2(1)
The speed of Vm — machine (m/s);
q1— vegetable production density (plant/ m3);
B— cuts (m);
Vs — first class conveyor belt speed (m/s);
The clamping thickness of d — vegetables in the conveyor belt (mm);
q2— is the concentration density of vegetables on the conveyor belt (m/s).
And so there's Vs =VmBq1/dq2=VmB /kd (2)
The k is the vegetable accumulation coefficient, the k=q1/q2,k is generally 18~33, dk=q1/q2,k 60 mm ..1
4.2 Calculation of secondary transport mechanism
The secondary conveyor belt needs to have a certain thickness of vegetable stacking. The relationship between the velocity Vd of the secondary conveyor belt and the thickness h the clamping layer can be obtained by analyzing its conveying principle
Vd =VsB /kh (3)
Formula Vd — the speed of the secondary conveyor belt;
h — the stacking height of vegetables on the secondary conveyor belt.
At the same time, in order to throw vegetables into the collection box, the end of the secondary conveyor belt should also meet the following conditions [8](see figure 6), that is
mrω2≥mgcosα(4)
The quality of m — vegetables (kg);
Radius of r— delivery wheels (mm);
ω— the angular velocity of the conveyor belt wheel (rad/s);
g— gravitational acceleration (m/s2);
α— the inclination of the conveyor belt.
As a result
ω≥√gcos α/r (5)
cause
Vd =rω(6)
So, so
Vd ≥√rgcos α(7)
For the most adverse case when cos α=1, the minimum limit is
Vmin ≥√rg (8)
Among them, the Vmin is the lowest limit value of the conveyor belt. So to sum up, the speed of the two-stage conveyor belt is Vd greater than Vmin. percent
By theoretical calculation, the range value of the velocity between the first stage conveyor belt and the second stage conveyor belt can be obtained. The q of rod diameter agglomeration coefficient between different leafy vegetables and the thickness of the clamping layer of the transported vegetables d different from the stacking height, which results in the value of the conveyor belt speed can not be obtained accurately. In order to ensure the harvest quality of leafy vegetables, it is necessary to carry out field experiments to determine the accurate value of conveyor belt speed.
5. Conclusions
By using the function tree to analyze, in order to meet the needs of leafy vegetables harvesting in most areas of China, a small intelligent automatic leafy vegetable harvester was designed, and the machine was determined to use battery as power. The cutting mechanism and stubble height adjustment mechanism were used to harvest leafy vegetables. The cutting amplitude and stubble adjusting mechanism make the machine better meet the actual operation requirements and have higher versatility. Through the theoretical calculation of the speed of the conveying mechanism, the range value of the vegetable conveying speed matching the walking speed is determined, but in order to better ensure the harvest quality of the vegetables, the field test of the whole machine is needed.
Compared with the traditional vegetable harvester, the small intelligent automatic leaf and vegetable harvester designed in this paper has the advantages of simple structure, easy manufacturing and processing, convenient operation, high working efficiency and guaranteed the quality of harvested vegetables. Therefore, vegetable harvester has great application prospect and development potential, but it needs further improvement in individual parts of machine, and the whole machine needs further test and analysis.
References:
[1] People's net, China vegetable area output per capita occupies the world first [EB/OL].] in the world http://scitech.people.com.cn/n/2014/0515/c1007-25019148.html.,2014-05-25
[2] State Council. National Planning for the Development of Modern Agriculture (2011-2015)[ EB/OL]. 2012-01-13 http://scitech.people.com.cn/n/2014/0515/c1007-25019148.html.
[3] Wang Jun, du Dongdong, Hu Jinbing. J]. on Mechanized Harvesting Technology and Development of Vegetables Journal of Agricultural Machinery ,2014,45(2):81-87.
[4] Chen Yongsheng, Hu Hui, Xiao Qiqiong, et al. Current Situation of Mechanization of Vegetable Production in China [J].] and Development Countermeasures Chinese Vegetables ,2015(10):1-5.
[5] Zhao Han, Huang Kang, Chen Ke. Design [M].] of Mechanical Systems Beijing: higher Education Press ,2005.
[6] Liu Siping, Liu Shuwu [M].] of Creative Methodology Harbin: Harbin University of Technology Press ,1998.
[7] Chinese Academy of Agricultural Mechanization. Manual for the Design of Agricultural Machinery (first volume)[ K].].1 Beijing: China Agricultural Science and Technology Press ,2007.
[8] Geng Duanyang, Zhang Daolin, Wang Xiangyou, et al .[ M].] of new agricultural mechanics Beijing: national Defense Industry Press ,2011.
Fund projects: Hebei Province Science and Technology support Project (15227209 D); Hebei Province vegetable Industry Technology system Project (2014)
小型智能葉菜類蔬菜收割機(jī)設(shè)計(jì)
高 龍，弋景剛,孔德剛，袁永偉
【摘 要】摘 要：目前，我國大部分葉菜類蔬菜收獲作業(yè)基本靠人工完成，收割效率低，且對(duì)蔬菜損傷較大。針對(duì)葉菜類蔬菜收割存在的問題，通過使用功能樹對(duì)機(jī)器功能進(jìn)行分析，設(shè)計(jì)了一種小型智能自動(dòng)化葉菜類蔬菜收割機(jī)。該機(jī)能夠根據(jù)蔬菜種類的不同，智能調(diào)節(jié)收割蔬菜的割幅寬度與割茬高度，并采用了電池直流驅(qū)動(dòng)技術(shù)、絲桿升降技術(shù)、雙向絲杠技術(shù)和分級(jí)傳動(dòng)技術(shù)。該收割機(jī)收割效率高，可保證蔬菜的收割品質(zhì)，滿足國內(nèi)大部分地區(qū)葉菜類蔬菜收割的需要。
【期刊名稱】農(nóng)機(jī)化研究
【年(卷),期】2016(000)009
【總頁數(shù)】4
【關(guān)鍵詞】蔬菜收割機(jī)；割幅調(diào)整；割茬調(diào)整
0 引言
據(jù)最新資料顯示：2014年，我國蔬菜面積達(dá)到0.2億hm2多，年產(chǎn)量超過7億t，人均占有量500kg多，均居世界第一位[1]。其中，設(shè)施蔬菜面積達(dá)386.2萬hm2，葉菜占設(shè)施蔬菜的50%[2]。由于不同葉菜類蔬菜之間的生態(tài)學(xué)特性各異，葉菜類蔬菜的統(tǒng)一收獲有著較大的難度，其收獲作業(yè)基本依靠人工完成；但葉菜生長周期短，收割即時(shí)性強(qiáng)、勞動(dòng)強(qiáng)度大、人工收割質(zhì)量難以控制，直接影響蔬菜品質(zhì)，降低了葉菜價(jià)值[3]。隨著勞動(dòng)力價(jià)格不斷上漲，人工收割費(fèi)用占蔬菜成本大幅度提高，市場急需一種智能化葉菜收割機(jī)械[4]。為此，設(shè)計(jì)了一種智能自動(dòng)化葉菜類蔬菜收割機(jī)，能夠根據(jù)蔬菜種類及收割要求的不同，對(duì)割幅和割茬高度進(jìn)行智能調(diào)節(jié)，并對(duì)關(guān)鍵工作部件進(jìn)行了優(yōu)化設(shè)計(jì)。該機(jī)充分利用電力資源，?盡可能地減輕機(jī)器作業(yè)時(shí)對(duì)環(huán)境的污染，使其滿足國內(nèi)大多數(shù)地區(qū)的葉菜類蔬菜的收割要求。
1 裝置方案擬定
為了能較好地設(shè)計(jì)出小型智能自動(dòng)化葉菜類蔬菜收割機(jī)的各部分功能，對(duì)收割機(jī)的功能進(jìn)行功能樹[5]的分析，分析結(jié)構(gòu)如圖1所示
根據(jù)創(chuàng)造方法的相關(guān)原理，建立能完成功能樹內(nèi)的各個(gè)功能形態(tài)學(xué)矩陣[6]，如表1所示。
根據(jù)形態(tài)學(xué)矩陣?yán)碚?為實(shí)現(xiàn)功能樹內(nèi)的功能，可以有2×3×3×3×2×3=324種方案。通過對(duì)國內(nèi)外市場上的類似產(chǎn)品的分析，對(duì)比各種執(zhí)行方式的優(yōu)劣并考慮到小型智能自動(dòng)化葉菜類收割機(jī)的成本、裝配的難易和可靠性等要求，確定最終方案選擇為盤式驅(qū)動(dòng)力輪行走、輸送帶輸送蔬菜、雙向絲杠割副調(diào)節(jié)、絲桿升降割茬調(diào)節(jié)、圓盤式切割器切割蔬菜，以及人工手動(dòng)啟停控制的方案。
2 總體結(jié)構(gòu)
葉菜類蔬菜收割機(jī)采用蓄電池做直流電源；在收割機(jī)的前端設(shè)置割茬高度調(diào)整機(jī)構(gòu)，由直流電機(jī)與絲桿升降機(jī)組成，絲桿升降機(jī)由直流電機(jī)驅(qū)動(dòng)進(jìn)行上下移動(dòng)；前端底部裝有割幅調(diào)節(jié)調(diào)節(jié)裝置，由電機(jī)進(jìn)行驅(qū)動(dòng)，也可由人工對(duì)割幅進(jìn)行微調(diào)；收割機(jī)的中部設(shè)置了蔬菜輸送機(jī)構(gòu)，由兩級(jí)輸送機(jī)構(gòu)組成，分別由兩個(gè)直流電機(jī)進(jìn)行動(dòng)力輸入；行走則由直流電機(jī)直接驅(qū)動(dòng)行走輪進(jìn)行移動(dòng)；收割機(jī)尾部設(shè)有蔬菜收集箱對(duì)蔬菜進(jìn)行收集。割茬調(diào)整機(jī)構(gòu)、分禾器、割幅調(diào)整機(jī)構(gòu)、輸送機(jī)構(gòu)、輸送直流電機(jī)、前進(jìn)扶手、控制箱、行走輪及收集箱全部裝在機(jī)架上，由直流電機(jī)驅(qū)動(dòng)的割刀布置在割幅調(diào)整機(jī)構(gòu)上，如圖2所示。
如圖2所示：直流電機(jī)與絲桿升降器直接連接，二者安裝在機(jī)架的前端;分禾器安裝在機(jī)架的前端中部；割幅調(diào)整機(jī)構(gòu)安裝在機(jī)架的前端下部，割刀則布置在割幅調(diào)整機(jī)構(gòu)上的割刀放置器上；輸送機(jī)構(gòu)前端安裝在割幅調(diào)整機(jī)構(gòu)的前端，中部布置在機(jī)架中部上，尾部則安裝在機(jī)架的尾部；蓄電池放置在機(jī)架的中下部；驅(qū)動(dòng)輪布置在蓄電池的下部與機(jī)架相連；控制箱安裝在機(jī)架的中部右側(cè)；蔬菜收集箱安裝在機(jī)架的尾部，前進(jìn)扶手與機(jī)架的尾部的凸起處相連。
工作時(shí)，確定好收割蔬菜種類，由控制箱發(fā)出信號(hào)，幅寬調(diào)整機(jī)構(gòu)與絲桿升降機(jī)進(jìn)行運(yùn)動(dòng)，使割刀運(yùn)動(dòng)到合適的收割位置，二者動(dòng)作停止。此時(shí)，割刀開始工作，行走輪在直流電機(jī)的驅(qū)動(dòng)下開始進(jìn)行行走；輸送機(jī)構(gòu)在輸送電機(jī)的帶動(dòng)下進(jìn)行動(dòng)作，輸送機(jī)構(gòu)中先由一級(jí)輸送裝置將收割的蔬菜進(jìn)行空間90°翻轉(zhuǎn)并運(yùn)送到二級(jí)輸送裝置上；二級(jí)輸送裝置將蔬菜輸送到蔬菜收集箱中。
3 關(guān)鍵部件設(shè)計(jì)
3.1 割幅調(diào)整機(jī)構(gòu)
割幅調(diào)整機(jī)構(gòu)由主調(diào)整機(jī)構(gòu)與微調(diào)機(jī)構(gòu)組成。主調(diào)整機(jī)構(gòu)主要包括直流電機(jī)、雙向絲杠及割刀放置器。微調(diào)整機(jī)構(gòu)包括小型雙向絲杠、手輪及幅寬控制器，如圖3所示。
整個(gè)調(diào)整機(jī)構(gòu)安裝在收割機(jī)支架的前端；直流電機(jī)通過聯(lián)軸器與雙向絲杠進(jìn)行連接，雙向絲杠上的方形螺母與割刀放置器連接在一起。直流電機(jī)轉(zhuǎn)動(dòng)時(shí)，雙向絲杠轉(zhuǎn)動(dòng)，帶動(dòng)方形螺母進(jìn)行直線移動(dòng)，從而實(shí)現(xiàn)了收割行距的調(diào)整。微調(diào)機(jī)構(gòu)中的小型雙向絲杠上的方形螺母直接固定幅寬控制器，通過搖動(dòng)兩側(cè)的手輪對(duì)幅寬控制器的間距進(jìn)行調(diào)整。微調(diào)機(jī)構(gòu)的主要作用是依靠人工對(duì)不同的蔬菜的夾持輸送寬度進(jìn)行調(diào)整。
3.2 割茬高度調(diào)整機(jī)構(gòu)
割茬高度調(diào)整機(jī)構(gòu)由直流電機(jī)、絲桿升降器及行走輪等組成，如圖4所示。
直流電機(jī)與絲桿升降器直接連接，兩個(gè)絲桿升降器之間由同步軸連接，絲桿升降器的絲桿下端分別安裝行走輪。
割茬調(diào)整機(jī)構(gòu)根據(jù)不同葉菜類蔬菜的種類與生長狀況，確定出不同的割茬高度?？刂蒲b置給出確定的信號(hào)，直流電機(jī)轉(zhuǎn)動(dòng)，帶動(dòng)絲桿升降機(jī)進(jìn)行升降運(yùn)動(dòng)，從而實(shí)現(xiàn)不同的種類與不同生長狀況的蔬菜具有不同的割茬高度。
3.3 輸送機(jī)構(gòu)
輸送機(jī)構(gòu)由一級(jí)輸送機(jī)構(gòu)與二級(jí)輸送機(jī)構(gòu)組成：一級(jí)輸送機(jī)構(gòu)主要包括前端豎置輸送小輪、橫置輸送輪及條形帶等;二級(jí)輸送機(jī)構(gòu)包括前后輸送輪、寬型輸送帶等，結(jié)構(gòu)如圖5所示。
一級(jí)輸送機(jī)構(gòu)安裝在蔬菜收割機(jī)的前端，條形帶一端安裝在豎置輸送小輪上，相鄰兩帶的另一端則分別放在上下兩個(gè)橫豎輸送輪上，可使用相鄰兩帶之間的夾持力輸送蔬菜。一級(jí)輸送機(jī)構(gòu)的主要作用是將收割上來的葉菜類蔬菜夾持輸送并將豎直蔬菜橫向放倒后送至二級(jí)傳送機(jī)構(gòu)；二級(jí)輸送機(jī)構(gòu)則將從一級(jí)輸送機(jī)構(gòu)輸送上來的蔬菜輸送至較高位置并將其拋入收集箱中。
4 蔬菜輸送速度的確定
輸送機(jī)構(gòu)是聯(lián)系割刀和收集箱的橋梁，其速度快慢直接影響整機(jī)的工作性能。輸送機(jī)構(gòu)既不能被堵塞也不能浪費(fèi)不必要的功率，同時(shí)要保證蔬菜在收集箱中有合適的堆放位置。為了更好地保證葉菜類蔬菜的收割品質(zhì)，有必要對(duì)輸送機(jī)構(gòu)的輸送速度進(jìn)行計(jì)算，得到與整機(jī)行走速度相匹配的輸送速度。
4.1 一級(jí)輸送機(jī)構(gòu)速度計(jì)算
一級(jí)輸送機(jī)構(gòu)主要靠條形帶的夾持力進(jìn)行蔬菜的輸送，輸送帶快則夾持蔬菜層薄，輸送帶慢則加持蔬菜層厚。這時(shí)輸送帶速度則應(yīng)該按指定的蔬菜堆疊厚度使輸送帶單位時(shí)間內(nèi)的蔬菜輸送量和機(jī)器收割量相等而確定[7]。即
VmBq1=Vsdq2 （1）
式中 Vm—機(jī)器前進(jìn)速度(m/s)；
q1—蔬菜生產(chǎn)密度(株/m3)；
B—割幅(m)；
Vs—一級(jí)輸送帶速度(m/s)；
d—蔬菜在輸送帶的夾持厚度(mm)；
q2—為蔬菜在輸送帶上的集聚密度(m/s)。
所以有Vs=VmBq1/dq2=VmB/kd （2）
其中，k為蔬菜積集系數(shù)，k=q1/q2，k一般取18~33，d≤60mm。
4.2 二級(jí)輸送機(jī)構(gòu)計(jì)算
二級(jí)輸送帶上需要有一定的蔬菜堆疊厚度。通過分析其輸送原理可以得到二級(jí)輸送帶的速度Vd與夾持層的厚度h關(guān)系為
Vd=VsB/kh (3)
式中 Vd—二級(jí)輸送帶的速度；
h—蔬菜在二級(jí)傳送帶上的堆疊高度。
同時(shí)，二級(jí)輸送帶的尾端為了將蔬菜拋入收集箱中，二級(jí)輸送帶還應(yīng)該滿足下列條件[8](見圖6)，即
mrω2≥mgcosα (4)
式中 m—蔬菜的質(zhì)量(kg)；
r—輸送輪的半徑(mm)；
ω—輸送帶輪的角速度(rad/s)；
g—重力加速度(m/s2)；
α—輸送帶的傾角。
因此有
ω≥√gcosα/r (5)
又因
Vd=rω (6)
所以
Vd≥√rgcosα (7)
當(dāng)cosα?=1時(shí)為最不利的情況，其最低極限值為
Vmin≥√rg (8)
其中，Vmin為輸送帶的最低極限值。所以綜上所述二級(jí)輸送帶的速度Vd大于Vmin。
通過理論計(jì)算可以得到一級(jí)輸送機(jī)構(gòu)輸送帶與二級(jí)輸送帶的速度的范圍值。由于不同葉菜類蔬菜之間的桿徑集聚系數(shù)q以及被輸送蔬菜的夾持層厚度d與堆疊高度h的不同，導(dǎo)致了輸送帶速度的值無法準(zhǔn)確得到。為了更好地保證葉菜類蔬菜的收割品質(zhì)，需要對(duì)收割機(jī)進(jìn)行實(shí)地試驗(yàn)來確定出輸送帶速度的準(zhǔn)確值。
5 結(jié)論
通過使用功能樹進(jìn)行分析，為滿足國內(nèi)大多數(shù)地區(qū)的葉菜類蔬菜收割，設(shè)計(jì)了小型智能自動(dòng)化葉菜類蔬菜收割機(jī)，并確定該機(jī)使用蓄電池作為動(dòng)力，以割幅調(diào)整機(jī)構(gòu)及割茬高度調(diào)整機(jī)構(gòu)，輸送機(jī)構(gòu)作為主要部件對(duì)葉菜類蔬菜進(jìn)行收割。割幅與割茬調(diào)整機(jī)構(gòu)使得該機(jī)更好地滿足了實(shí)際作業(yè)需求，且具有更高的通用性。通過對(duì)輸送機(jī)構(gòu)速度的理論計(jì)算，確定出與行走速度相匹配的蔬菜輸送速度范圍值；但為了更好的保證蔬菜的收割質(zhì)量，需對(duì)整機(jī)進(jìn)行實(shí)地試驗(yàn)。
相比于傳統(tǒng)的葉菜類蔬菜收割機(jī)，本文所設(shè)計(jì)的小型智能自動(dòng)化葉菜類收割機(jī)結(jié)構(gòu)簡單、制造加工容易、操作使用方便、工作效率高且能保證被收割蔬菜品質(zhì)。因此，蔬菜收割機(jī)具有很大的應(yīng)用前景和發(fā)展?jié)摿?，但在機(jī)器中個(gè)別零部件處需進(jìn)一步的改進(jìn)，整機(jī)需要進(jìn)一步的試驗(yàn)分析。
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基金項(xiàng)目：河北省科技支撐計(jì)劃項(xiàng)目(15227209D)；河北省蔬菜產(chǎn)業(yè)技術(shù)體系項(xiàng)目(2014)
1iJOE ? Vol. 14, No. 3, 2018
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