蔬菜移栽機(jī)在發(fā)展中國家的展望外文文獻(xiàn)翻譯、中英文翻譯
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外 文 翻 譯 單行蔬菜缽體苗自動(dòng)移栽機(jī)的設(shè)計(jì)—取苗裝置設(shè)計(jì) 原文1:Vegetable Transplanters for Use in Developing Countries—A Review 譯文1:蔬菜移栽機(jī)在發(fā)展中國家的展望 原文2:Development of a mechanism for transplanting rice seedlings 譯文2:移栽水稻幼苗機(jī)制和發(fā)展 原文1: Developing countries contribute 72% of the total vegetable production in the world. The transplanting operation is one of the most labor intensive in vegetable production. It is largely done by hand in India and most developing countries and incurs large investments in labor, time,and cost. This article presents the details of construction of vegetable transplanters in addition to recent advances in their development.Performance of transplanters under actual field conditions is discussed. Traditional Methods of Transplanting Vegetable Seedlings Ferminger (1953) reported that in India, for small-scale vegetable gardening, holes of 60 cm diameter and 30 cm deep are manually dug in the field at desired spacings. The soil is mixed with farmyard manure, bone meal,and wood ashes. The hole is then filled to a depth of 15–20 cm and packed. A seedling is placed in the middle of the hole and topsoil is filled around the seedling, compacted, firmed, and soaked with water. A shelter is built to shade the seedling under dry weather conditions. This method does not require any field preparation. A shovel or spade is the only implement used. Classification of Vegetable Transplanters and Seedlings Transplanters are designed based on seedling type to be used. The semiautomatic transplanters can be used for almost all types of seedlings (Table 1). The bare root seedlings are obtained by pulling seedlings directly from nursery beds. The soil block seedlings are obtained by sowing of seeds in moist soil cubes made by mixing soil, peat, compost,and sand (Press, 2001). The cell mold seedlings are grown in flexible plastic (Tsuga, 2000) or heavy-duty injection-molded trays(Horticultural Supplies Co., Mumbai, India) with cells to fill with the soil mix and sow the seed. Trays can contain 128, 200, or 288 cells, in which the arrangement of cells is 8 16, 10 20, and 12 24, respectively(Tsuga, 2000). The Horticultural Supplies Co. tray has five sections,each with 30 or 40 cells, supported by an outer tray, which can hold 150 or 200 seedlings. The shape of the cell is an inverted truncated pyramid. Another method for transplant production is the paper pot,generally made from recycled paper. Paper pots provide an individual area for each seed to germinate and the plant to develop (Indian Institute of Horticultural Research [IIHR], 2006). A total of 128 or 200 pots can be placed on a tray in 8 8 or 10 10 arrangements (Tsuga,2000).Semiautomatic and fully automatic transplanters can be used for plantingcell mold and paper pot–produced seedlings. The linked paper pot,or a chain of pots prepared by connecting a series of paper pots, is made by joining two-ply sheets of paper with water-resistant adhesive(Nambu and Tanimura, 1992). They do not require a tray for holding seedlings but require an arrangement to separate the chain of pots into individuals before feeding them to the planting unit. Linked paper pots are used only with fully automatic transplanters. The walking-type semiautomatic transplanters are either self-propelled or hand tractor–operated machines. They are rare because the operator has to concentrate on the operation of the machine and feeding the seedlings.Riding-type two-row or three-row semiautomatic transplanters are tractor mounted or tractor pulled machines, whereas those that are used with more rows are tractor pulled. The walking-type automatic transplanters are self-propelled machines for sowing a maximum of four rows. Ridingtype automatic transplanters are either self-propelled (up to four rows) or tractor pulled (up to eight rows). Further, Marr (1994) described types of transplanters called punch planters (automatic) and water-wheel planters (semiautomatic). The punch planters transplant through plastic mulches by puncturing the mulch and the soil and setting the seedling into the holes. The water-wheel planters are similar to the punch planters with the addition of a large tank filled with water or fertilizer solution. As the hole is formed for the transplant, a portion of the solution is injected into the transplant hole. Seedlings are hand-set into the watered hole by operators riding low near the ground (Model 1600 of Robert Marvel Plastic Mulch, Annville, Pa.). As the seedling is pushed in, mud from the bottom comes up along the sides and covers the top to complete the transplanting operation. Munilla and Shaw (1987) described a dibbling transplanter in which holes are made in the soil and seedlings are planted in the holes. Seedling Box or Tray Holder A seedling box is provided on semiautomatic transplanters to store bare root seedlings for feeding to the planting unit. It is rectangular in cross section and is open at the top. Long rectangular seedling boxes are used in transplanters (Model 2000, Mechanical Transplanter Co., Holland, Mich.)used for planting long seedlings, in which a conveyor belt is provided,which can be driven by foot action. Carrousel tray holders (Figure 1) can also be used in transplanters (Mechanical Transplanter Co.’s models 5000,5000W, 5000WD, 4000, and 6000) that use cell mold seedlings. Each tray holder stores four to six trays, each carrying 200 cell mold seedlings. In automatic transplanters, the tray is kept at a place with its orientation suitable for the pick-up device to remove seedlings from trays. It also has a mechanism to move trays forward as seedlings are removed from the tray. Recent advances in the design of vegetable transplanters. Apart from the essential components for efficient planting of vegetable seedlings, vegetable transplanters are provided with systems for maintaining the accuracy, precision, and effectiveness in planting seedlings with minimum human intervention. Researchers have reported recent developments in automatic vegetable transplanter in the United States (Parish,2005), Italy, Japan, Australia, and England (Labowsky, 2001). Robotic transplanters have been developed (Brewer, 1994; Kim et al., 1995;Ryu et al., 2001; Sakaue, 1992; Tai et al., 1994), and Figure 7 presents a schematic diagram for this type of transplanter developed by Ryu et al.(2001). It has a CCD camera, which identifies empty cells in high-density plug trays, passes this information to the computer, which feeds it to the manipulator. The manipulator actuates the end-effecter to pick up only the good-quality seedlings to the low-density growing trays. The labor and time involved in discarding the poor-quality seedlings are fully FIGURE 7. Schematics of the robotic transplanter: (a) the front view of the manipulator (b) the side view of the manipulator, the tray moving system,and the vision system (Ryu et al., 2001). Reprinted with permission of the Institute of Agricultural Engineers, UK. Further, a camera linked to a computer feeds the information on the leaf direction of the good-quality seedlings and the manipulator accordingly orients the end-effecter to pick up the seedlings. The lowdensity growing trays used for transplanting will have 100% good-quality seedlings without any human intervention. In machines employing the belt conveyor–type planting unit (Series TP Transplanter of FMC Food Tech Agricultural Machinery Division, Collecchio-Parma, Italy), faulty seedlings are separated using a machine vision system. It is claimed that the mechanism has been developed to compensate for the deficit caused by removing faulty seedlings by momentarily increasing the feed rate of seedlings from the tray (Thijssen, 2000). Photo-cells are being used to detect the gaps and replace them with new seedlings (Lannen Plant Systems, Victoria,Australia). The desired plant spacing in the field can be entered into the computer and encoders are provided to read the distance traveled along the ground and plant the seedlings within 1-mm accuracy. The seedling planting depth can be electronically controlled. This is useful particularly in lettuce, where if seedlings are planted exactly level with the top of the soil,leaf rot will be minimized and development of lettuce into an oval rather than round shape will be reduced. The pressure applied by the soil compacting device can be controlled depending on the type of soil and its condition. Seedlings can be automatically planted at the speed of 2 seedlingss?1 (Model G4 vegetable transplanter, Williames Hi-tech International Pvt. Ltd., Victoria,Australia). The machine can carry 35 trays with 260 seedlings each, eliminating time lost for loading of seedling trays by at least 1 h. A transplanter with the ability to adjust the seedling pick-up unit based on size and configuration of trays has been developed (Sena, 2006). The field performance of vegetable transplanters depends on the feeding rate of the seedling pick-up unit (for automatic transplanters), planting rate of the seedling planting unit, spacing between seedlings in a row, row spacing, and achievable optimum speed of operation to minimize missed plantings in addition to field, crop, and other operating parameters. Most researchers and manufacturers have reported data on planting rate and seedling feed rate rather than on field performance of machines. CIAE(2004) reported forward speed as 0.9 kmh?1 and field capacity (field area plantedh?1) as 0.1 hah?1 for planting tomato at a 60-cm row spacing and 45-cm in-row plant spacing using a tractor-drawn two-row semiautomatic transplanter with pocket-type planting unit. The field performance of a two-row tractor-mounted semiautomatic transplanter with pocket-type planting unit developed by PAU (2004) is presented in Table 4. The suitable forward speed of operation for obtaining a minimum of missed plantings was found to be from 0.9 to 1.1 kmh?1 for various crops. Increasing speed increased the percentage of missed plantings and necessitates that two laborers feed the single row to maintain the percentage missing within acceptable limits. Holland Transplater Co.’s models 1500, FWD 1500, and 1600, and Mechanical Transplanter Co.’s models 1000, 1000B-3,1000 2, 1980 nursery transplanter, 2000, and 22C have the provision for two laborers to feed the single row. Marr (1994) opined that the transplanter has to be operated at a speed that allows careful placement and attention to problems that develop. Operators should not be so involved in placing plants in the machine that they cannot watch for problems that develop. A rotary cup–type planting unit on a semiautomatic transplanter allowed for higher forward speed than that of a pocket-type planting unit(Labowsky, 2001). An average forward speed of 1.4 kmh?1 and field capacity of 0.14 hah?1 for planting tomato, cauliflower, chile peppers,and eggplant using a three-row semiautomatic transplanter with rotary cup–type planting unit has been reported (Tamil Nadu Agricultural University [TNAU], 2004). For reasonable seedling spacing, the feed rate clearly limits the maximum allowable travel speed of the transplanting machine (Srivastava et al., 2006). Minoru Industrial Co. Ltd. (Okayama,Japan) claims that its two-row self-propelled walking-type automatic vegetable transplanter can plant 0.2 hah?1. Tsuga (2000) found that the two-row fully automatic transplanter was able transplant 0.11 hah?1 while operating at a speed of 1.2–1.4 kmh?1 for cabbage at a plant spacing of 30 cm and an in-row spacing of 60 cm. There was less than 3% missed plantings. Kim et al. (2001) reported that the field capacity of a prototype two-row automatic transplanter for cabbage of 0.1 hah?1 with 3.5% missed plantings.Srivastava et al. (2006) opined that an important performance criterion for transplanters is that seedlings must be oriented properly and in good contact with the soil. A successful planting has been defined as having seedlings inclined less than 30 from the vertical (Munilla and Shaw, 1987). 作者:G. V. Prasanna Kumar ; H. Raheman 出處:International Journal of Vegetable Science,Vol.14,No.3,232-255 譯文1: 發(fā)展中國家占世界蔬菜總生產(chǎn)的72%。移栽技術(shù)是一種最密集型的蔬菜生產(chǎn)勞動(dòng)。它主要是在印度手工完成和大多數(shù)發(fā)展中國家把大量的資源投資在人力、時(shí)間、和成本。本文介紹了蔬菜移栽機(jī),除了最新的一些進(jìn)展和研究發(fā)現(xiàn),是在移栽機(jī)實(shí)現(xiàn)其特定性能條件下討論。 傳統(tǒng)方法的移植蔬菜種苗。 Ferminger(1953)報(bào)道說,在印度對(duì)于小規(guī)模的蔬菜園種植,孔的直徑是60厘米,深30厘米是手工挖場(chǎng)在理想狀態(tài)下的空隙。土壤是混合堆肥,骨粉,和木灰。這個(gè)洞是的深度15 - 20厘米。一個(gè)幼苗被放置在中間孔上和表層周圍被土所包圍,圍繞著種苗,將其壓實(shí),壓牢固 ,再進(jìn)行灌水。一個(gè)理想適當(dāng)?shù)沫h(huán)境是建立樹蔭下的幼苗干旱的天氣條件。這種方法不需要任何現(xiàn)場(chǎng)準(zhǔn)備,一個(gè)鏟或鋤頭僅僅使用一種工具。 蔬菜的分類移栽機(jī)和秧苗。 印度孟買的一家園藝有限公司,對(duì)此進(jìn)行了開發(fā)研究,其讓細(xì)胞充滿土壤與之充分混合,隨后播下種子。試驗(yàn)中鎖使用的托盤可以容載128、200或288個(gè)細(xì)胞,再進(jìn)行整齊排列,將細(xì)胞排列到816、1020。2424幾種排列托盤中(Tsuga,2000)。 園藝用品有限公司的托盤有五個(gè)部分,每個(gè)有30或40個(gè)細(xì)胞,由一個(gè)外托盤盛載,可以容納150或200顆蔬菜苗。而細(xì)胞的形狀是一個(gè)反向的被截?cái)嗟慕鹱炙煨汀A硪粋€(gè)方法是移植生產(chǎn),一般用可再生環(huán)保紙。環(huán)保紙盆提供一個(gè)個(gè)人面積為每個(gè)種子發(fā)芽和植物開發(fā)所需要的空間(印度理工學(xué)院園藝研究[IIHR],2006)。總共有128或200盆可以被放置在一個(gè)88或1010的托盤中整齊排列 (Tsuga,2000)。而半自動(dòng)和全自動(dòng)移栽機(jī)可以用于種植電池模具和紙罐生產(chǎn)的種苗。鏈接的紙盆,或一連串的準(zhǔn)備通過連接一個(gè)系列的紙盆,是由通過加入兩層的紙張?jiān)儆梅浪z加工(Nambu和Tanimura,1992)。 他們雖然不需要一個(gè)托盤來排列但是他們需要安排一個(gè)人在喂食他們種植單位前使幼苗分離鏈形成,而環(huán)保紙盆只能使用全自動(dòng)移栽機(jī)。 步行式半自動(dòng)移栽機(jī)一種是手推式操作機(jī)器,另一種是裝載于手扶式拖拉機(jī)上的操作機(jī)器。它們并不常見,這是因?yàn)榻?jīng)營者專注于機(jī)器的操作和喂苗。還有一種騎式雙排渦輪和由三行組成的半自動(dòng)移栽機(jī)是在拖拉機(jī)上安裝或拖拉機(jī)拉動(dòng)的機(jī)器,而那些使用更多的是由拖拉機(jī)來提供拉動(dòng)力。蔬菜移栽機(jī)的步行式和自動(dòng)式都是自航機(jī)械,播種最多4行。Ridingtype自動(dòng)移栽機(jī)要么自航(最多4行)或拖拉機(jī)拉(8行)。進(jìn)一步,馬爾(1994)所描述的移栽機(jī)類型稱為穿孔種植者(自動(dòng))和水輪播種機(jī)(半自動(dòng))。沖頭通過塑料薄膜種植移植由穿孔薄膜與土壤設(shè)置幼苗進(jìn)入洞口。種植園主和水輪相似的穿孔種植園還添加了一個(gè)大水箱并將其注滿水或肥料溶液。隨著孔形成的移植,一部分營養(yǎng)液和肥料注入移植孔。進(jìn)澆苗洞并手工精制,運(yùn)營商地面附近騎低(型號(hào)1600的羅伯特奇跡塑料覆蓋物,Annville,Pa。)。 隨著秧苗的推進(jìn),泥漿從底部出現(xiàn)并沿兩側(cè)和頂部覆蓋同時(shí)完成移植操作。Munilla和蕭伯納(1987)描述了一種穴播插秧機(jī)在這洞是土壤和苗種植的洞。 苗箱和托盤架。 一株幼苗盒子是提供半自動(dòng)移栽機(jī)存儲(chǔ)的根幼苗喂種植單位。它呈矩形其橫截面和是開在頂部。長矩形育苗盒用于移栽機(jī)(型號(hào)2000,機(jī)械插秧機(jī)有限公司,荷蘭,米奇。)用于種植長苗,用傳送帶進(jìn)行傳送,這可以由人力來代替。旋轉(zhuǎn)托盤也可用于移栽機(jī)(機(jī)械插秧機(jī)公司的模型5000,5000 w,wd 5000、4000和6000),使用電池模具苗。每個(gè)托盤持有人有4到6個(gè)托盤,每個(gè)托盤載有200左右細(xì)胞型苗。在自動(dòng)移栽機(jī)中托盤是保存在一個(gè)地方,其取苗機(jī)構(gòu)為傳感器裝置取出幼苗到托盤。它也有一個(gè)機(jī)制向前移動(dòng)托盤苗移開從托盤。 現(xiàn)行設(shè)計(jì)的最新進(jìn)展蔬菜移栽機(jī)。 除了基本組件為高效種植的蔬菜苗,蔬菜移栽機(jī)提供系統(tǒng)維護(hù)的準(zhǔn)確性、有效性和精準(zhǔn)性,在種植幼苗與最小的人工干預(yù)。研究人員報(bào)道最近的自動(dòng)蔬菜插秧機(jī)進(jìn)展是在美國的 (教區(qū),2005)、意大利、日本、澳大利亞和英國(Labowsky,2001)。機(jī)器人移栽機(jī)已經(jīng)開發(fā)(布魯爾,1994;金et al。,1995;Ryu et al。,2001;Sakaue,1992;大et al,1994年),并提出了原理圖的這種類型的插秧機(jī)Ryu開發(fā)的et al。(2001)。 它有一個(gè)CCD攝像機(jī),它能識(shí)別空細(xì)胞高密度塞托盤,并將這些信息傳送給計(jì)算機(jī),讓它來代替機(jī)械手。機(jī)械手的促動(dòng)端區(qū)只撿優(yōu)質(zhì)的種苗到低密度增長托盤。勞動(dòng)和時(shí)間參與完全丟棄劣質(zhì)苗。英國制造的電路圖的機(jī)器人插秧機(jī),其機(jī)械手,托盤運(yùn)動(dòng)系統(tǒng),和視覺系統(tǒng)(Ryu et al。,2001)。 進(jìn)一步的,一個(gè)相機(jī)與電腦提要信息方向和機(jī)械手的優(yōu)質(zhì)種苗因此主導(dǎo)的端區(qū)撿起苗。低密度種苗的日益增長的托盤用于移植會(huì)有100%的高質(zhì)量苗,無需人工干預(yù)。在機(jī)器使用皮帶輸送機(jī)來傳送種植單位(TP插秧機(jī)的FMC食品系列科技農(nóng)業(yè)機(jī)械部門,Collecchio-Parma、意大利),故障苗是分開使用機(jī)器的視覺系統(tǒng)。它聲稱機(jī)制已被開發(fā),以彌補(bǔ)種苗劣質(zhì)的幼苗,瞬間增加取苗量,種苗從托盤中取出(Thijssen,2000)。 細(xì)胞被用來檢測(cè)差距,代之以新的苗(Lannen植物系統(tǒng),維多利亞,澳大利亞)。 所需的植物間距在字段可以輸入到計(jì)算機(jī)和編碼器提供閱讀的距離沿地面和植物的幼苗在1毫米的精度。苗木種植深度可以電子控制。這是很有用,特別是在生菜,如果苗種植完全頂部的水平上土,葉腐病將會(huì)最小化和發(fā)展生菜成橢圓形而非圓的形狀將減少。壓力由土壤壓實(shí)的應(yīng)用設(shè)備可以控制取決于類型的土壤和條件。幼苗可以自動(dòng)種植幼苗的速度2?1(模型s G4嗎蔬菜插秧機(jī),Williames高科技國際經(jīng)紀(jì)有限公司,維多利亞,澳大利亞)。這臺(tái)機(jī)器可以攜帶260苗35托盤每,消除失去時(shí)間來裝載苗盤至少1 h。一個(gè)插秧機(jī)與適應(yīng)能力的幼苗拾音器單位根據(jù)大小和配置托盤已經(jīng)發(fā)達(dá)(塞納,2006)。 蔬菜移栽機(jī)現(xiàn)場(chǎng)性能取決于幼苗拾取單元的攝食率(自動(dòng)移栽機(jī)的插秧機(jī)),種植率,幼苗在一排之間的間距,行間距,并能達(dá)到的最佳的運(yùn)行速度,減少差錯(cuò)率,錯(cuò)過了種植作物,和其他操作參數(shù)。大多數(shù)研究人員和制造商已經(jīng)報(bào)道的種植率和幼苗的進(jìn)給速率,而不是在機(jī)器工作現(xiàn)場(chǎng)的性能數(shù)據(jù)。中國原子能科學(xué)研究院(2004)報(bào)道的前進(jìn)速度為0.9公里和田間持水量(田間種植面積)為0.1公頃以行距60厘米和45厘米使用拖拉機(jī)牽引兩行半自動(dòng)移栽機(jī)袋式栽培行株距種植番茄的單位。一二行拖拉機(jī)田間表現(xiàn)安裝半自動(dòng)移栽機(jī)袋式栽培單元由加索爾(2004)給出了。為獲得最小漏種植手術(shù)合適的前進(jìn)速度是從0.9到1.1公里多種作物。增加的速度增長百分比,錯(cuò)過了種植需要兩個(gè)工人保持在可接受的范圍內(nèi)的飼料比例失調(diào)的單排。荷蘭栽植機(jī)有限的模型1500,前進(jìn)1500,和1600,和機(jī)械插秧機(jī)有限的模型1000b-31000 1000,2,1980和2000,苗木移栽機(jī),有兩個(gè)工人養(yǎng)活22c單排的規(guī)定。馬爾(1994)認(rèn)為插秧機(jī)必須在速度進(jìn)給上給出合理適當(dāng)?shù)臄?shù)值,需要進(jìn)行精心安排和注意問題的研究探討,開發(fā)操作。轉(zhuǎn)杯–型種植單元在半自動(dòng)移栽機(jī)允許更高的速度比一個(gè)袖珍型種植單位(labowsky,2001)。一個(gè)正向平均速度為1.4公里和田種植西紅柿,花椰菜,辣椒0.14公頃的容量,并使用一三行半自動(dòng)移栽機(jī)轉(zhuǎn)杯–型種植單位茄子(泰米爾納德邦農(nóng)業(yè)大學(xué)[ TNAU ],2004)。合理的株距,進(jìn)給速度合理,有明顯界限的插秧機(jī)允許的最大行駛速度(Srivastava等人。,2006)。稔實(shí)業(yè)有限公司(岡山,日本)聲稱其兩行自走式自動(dòng)蔬菜移栽機(jī)可以種植0.2公頃。長苞鐵杉(2000)發(fā)現(xiàn),兩行全自動(dòng)移栽機(jī)可以移植0.11公頃而在速度為1.2白菜1.4公里在30厘米, 60厘米行株距株距操作,有小于3%的種苗錯(cuò)過了播種?;返热耍?001)報(bào)道,用3.5%的0.1公頃的白菜原型兩排自動(dòng)插秧機(jī)場(chǎng)容量錯(cuò)過了播種。Srivastava等人(2006)認(rèn)為,插秧機(jī)一個(gè)重要的性能指標(biāo)是幼苗必須正確定向并且與土壤接觸良好。一個(gè)成功的種植已被定義為幼苗傾斜小于30(穆尼利亞和肖,1987)。 原文2: Transplanting of seedlings is a labor intensive operation in the cultivation of rice. It is also a skilled job and involves working with a stooping posture in a puddled field. There exists a need to mechanize this operation. For this purpose the design of a mechanism was carried out following the method of analytical synthesis. A planar four-bar linkage with coupler extension was selected as the basic design. The path generated by the mechanism was plotted on a computer screen. By varying the dimensions of various links in the mechanism different paths of output motion of the coupler point were obtained. The potential link dimensions were identified based on the suitability of the path for picking, conveying and planting of seedlings as well as the return motion. A four-row self-propelled transplanter using the above mechanism and an optimized-planting finger was then developed and tested. The machine transplanting system was found to be technically viable. India is predominantly an agricultural country with rice as one of its main food crop. It produces about 80 million tons rice annually, which is about 22% of the world rice production.Culturally, transplanting of young seedlings of 20–35 days age in water-inundated field is preferred over direct seeding. The former leads to better yield due to better crop management practices that are possible in a transplanted crop. The operation of transplanting requires large amount of manpower (about 400 man-hour/ha) and the task is very laborious involving working in a stooping posture and moving in muddy field. Hence, this is considered as an activity that needs mechanization. Mechanization of transplanting facilitates mechanization of subsequent activities also in the production of the crop. The machines that are already successful in Japan and Korea could not be adopted in India because of economic cost constraints and due to the prevailing cultural practices of this country. Design of planting mechanisms used in power operated transplanters. Anon. states that most of the planting devices of power operated transplanters can be classified as crank and rocker mechanisms of four-bar linkage. A planting finger, which is a part of the coupler link of the mechanism, separates the seedlings from the seedling tray and places them in the soil. The curve traced by the planting finger may have an influence on the stability of the planted seedlings. The kinematic analysis of the planting mechanisms is considered essential for an understanding of its operation and its further improvements. Design of mechanism Erdman and Sandor state most mechanism tasks require a single input to be transferred to a single output. Therefore, single-degree-of-freedom mechanisms are the forms used most frequently.Shigley states that Grubler’s criterion is concerned with the numbe r of links in the mechanism and with the numbe r and kinds of kinematic pairs. It can be used for determining the degree of freedom of a mechanism. Erdman and Sandor state that analysis techniques can be used to replace costly and time consuming building and testing of physical prototypes in a trial and error design process. Analysis techniques generally form a basic part of most synthesis methods. Norton states that the four-bar linkage should be among the first solutions to motion control problems to be investigated. The fewest parts that can do the job will usually give the least expensive and most reliable solution. Norton states that the Grashof condition can be used as a very simple relationship, which predicts the behavior of a four-bar linkage, based on the link lengths. Zimmerman states that a four-bar mechanism is physically impossible if one of the links has a length greater than the sum of the other three. Hirschhorn states that in a four-bar linkage distinct types of mechanisms could be obtained by inversion. A crank-rocker mechanism is obtained by fixing one of the two links paired with the shortest link. Paul suggested that Newton–Raphson method could used be used to solve the non-linear equations developed for solving the four-bar linkage position problem. Zimmerman states that one basic mechanism design problem for which the four-bar chain- 1.請(qǐng)仔細(xì)閱讀文檔,確保文檔完整性,對(duì)于不預(yù)覽、不比對(duì)內(nèi)容而直接下載帶來的問題本站不予受理。
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