马铃薯播种机的性能评估外文翻译、外文文献翻译、机械类中英文翻译

1、马铃薯播种机的性能评估外文翻译、外文文献翻译、机械类中英文翻译 Assessment of the Behaviour of Potatoes in a Cup-belt PlanterH Buitenwerf WB Hoogmoed P LerinkJMullerFarm Technology Group Wageningen University PO Box 17 6700 AA Wageningen The Netherlandse-mail of corresponding author willemhoogmoedwurnlKrone GmbH Heinrich-Krone Str

2、asse 10 48480 Spelle GermanyIB-Lerink Laan van Moerkerken 85 3271AJ Mijnsheerenland The NetherlandsInstitute of Agricultural Engineering University of Hohenheim D-70593 Stuttgart Germany Received 27 May 2005 accepted in revised form 20 June 2006 published online 2 August 2006 The functioning of most

3、 potato planters is based on transport and placement of the seed potatoes by a cup-belt The capacity of this process is rather low when planting accuracy has to stay at acceptable levels The main limitations are set by the speed of the cup-belt and the number and positioning of the cups It was hypot

4、hesised that the inaccuracy in planting distance that is the deviation from uniform planting distances mainly is created by the construction of the cup-belt planterTo determine the origin of the deviations in uniformity of placement of the potatoes a theoretical model was built The model calculates

5、the time interval between each successive potato touching the ground Referring to the results of the model two hypotheses were posed one with respect to the effect of belt speed and one with respect to the inuence of potato shape A planter unit was installed in a laboratory to test these two hypothe

6、ses A high-speed camera was used to measure the time interval between each successive potato just before they reach the soil surface and to visualise the behaviour of the potatoThe results showed that a the higher the speed of the cup-belt the more uniform is the deposition of the potatoes and b a m

7、ore regular potato shape did not result in a higher planting accuracyMajor improvements can be achieved by reducing the opening time at the bottom of the duct and by improving the design of the cups and its position relative to the duct This will allow more room for changes in the cup-belt speeds wh

8、ile keeping a high planting accuracy1 IntroductionThe cup-belt planter Fig 1 is the most commonly used machine to plant potatoes The seed potatoes are transferred from a hopper to the conveyor belt with cups sized to hold one tuber This belt moves upwards to lift the potatoes out of the hopper and t

9、urns over the upper sheave At this point the potatoes fall on the back of the next cup and are conned in a sheet-metal duct At the bottom the belt turns over the roller creating the opening for dropping the potato into a furrow in the soilCapacity and accuracy of plant spacing are the main parameter

10、s of machine performance High accuracy of plant spacing results in high yield and a uniform sorting of the tubers at harvest McPhee et al 1996 Pavek Thornton 2003 Field measurements unpublished data of planting distance in The Netherlands revealed a coefcient of variation CV of around 20 Earlier stu

11、dies in Canada and the USA showed even higher CVs of up to 69 Misener 1982 Entz LaCroix 1983 Sieczka et al 1986 indicating that the accuracy is low compared to precision planters for beet or maizeTravelling speed and accuracy of planting show an inverse correlation Therefore the present cup-belt pla

12、nters are equipped with two parallel rows of cups per belt instead of one Doubling the cup row allows double the travel speed without increasing the belt speed and thus a higher capacity at the same accuracy is expectedThe objective of this study was to investigate the reasons for the low accuracy o

13、f cup-belt planters and to use this knowledge to derive recommendations for design modications eg in belt speeds or shape and number of cupsFor better understanding a model was developed describing the potato movement from the moment the potato enters the duct up to the moment it touches the ground

14、Thus the behaviour of the potato at the bottom of the soil furrow was not taken into account As physical properties strongly inuence the efciency of agricultural equipment Kutzbach 1989 the shape of the potatoes was also considered in the modelTwo null hypotheses were formulated 1 the planting accur

15、acy is not related to the speed of the cup-belt and 2 the planting accuracy is not related to the dimensions expressed by a shape factor of the potatoes The hypotheses were tested both theoretically with the model and empirically in the laboratory2 Materials and methods21 Plant materialSeed potatoes

16、 of the cultivars cv Sante Arinda and Marfona have been used for testing the cup-belt planter because they show different shape characteristics The shape of the potato tuber is an important characteristic for handling and transporting Many shape features usually combined with size measurements can b

17、e distinguished Du Sun 2004 Tao et al 1995 Zodler1969 In the Netherlands grading of potatoes is mostly done by using the square mesh size Koning de et al 1994 which is determined only by the width and height largest and least breadth of the potato For the transport processes inside the planter the l

18、ength of the potato is a decisive factor as well A shape factor S based on all three dimensions was introducedwhere l is the length w the width and h the height of the potato in mm with howol As a reference also spherical golf balls with about the same density as potatoes representing a shape factor

19、 S of 100 were used Shape characteristics of the potatoes used in this study are given in Table 122 Mathematical model of the processA mathematical model was built to predict planting accuracy and planting capacity of the cup-belt planter The model took into consideration radius and speed of the rol

20、ler the dimensions and spacing of the cups their positioning with respect to the duct wall and the height of the planter above the soil surface Fig 2 It was assumed that the potatoes did not move relative to the cup or rotate during their downward movementThe eld speed and cup-belt speed can be set

21、to achieve the aimed plant spacing The frequency fpot of potatoes leaving the duct at the bottom is calculated as where vc is the cup-belt speed in ms-1 and xc is the distance in m between the cups on the belt The angular speed of the roller or in rad s -1 with radius rr in m is calculated asThis ga

22、p xrelease in m is reached at a certain angle arelease in rad of a cup passing the roller This release angle arelease Fig 2 is calculated aswhere rc is the sum in m of the radius of the roller the thickness of the belt and the length of the cup and xclear is the clearance in m between the tip of the

23、 cup and the wall of the ductWhen the parameters of the potatoes are known the angle required for releasing a potato can be calculated Apart from its shape and size the position of the potato on the back of the cup is determinative Therefore the model distinguishes two positions a minimum re-quired

24、gap equal to the height of a potato and b imum required gap equal to the length of a potato The time trelease in s needed to form a release angle ao is calculated asCalculating trelease for different potatoes and possible positions on the cup yields the deviation from the average time interval betwe

25、en consecutive potatoes Combined with the duration of the free fall and the eld speed of the planter this gives the planting accuracyWhen the potato is released it falls towards the soil surface As each potato is released on a unique angular position it also has a unique height above the soil surfac

26、e at that moment Fig 2 A small potato will be released earlier and thus at a higher point than a large oneThe model calculates the velocity of the potato just before it hits the soil surface uend in ms-1 The initial vertical velocity of the potato v0 in ms-1 is assumed to equal the vertical componen

27、t of the track speed of the tip of the cupwhere yr in m is the distance between the centre of the roller line A in Fig 2 and the soil surfaceThe time of free fall tfall in s is calculated withwhere g is the gravitational acceleration 98ms2 and the nal velocity vend is calculated aswith v0 in ms-1 be

28、ing the vertical downward speed of the potato at the moment of releaseThe time for the potato to move from Line A to the release point trelease has to be added to tfallThe model calculates the time interval between two consecutive potatoes that may be positioned in different ways on the cups The lar

29、gest deviations in intervals will occur when a potato positioned lengthwise is followed by one positioned heightwise and vice versa23 The laboratory arrangementA standard planter unit Miedema Hassia SL 4 6 was modied by replacing part of the bottom end of the sheet metal duct with similarly shaped t

30、ransparent acrylic material Fig 3 The cup-belt was driven via the roller 8 in Fig 1 by a variable speed electric motor The speed was measured with an infrared revolution meter Only one row of cups was observed in this arrangement A high-speed video camera SpeedCam Pro Wein-berger AG Dietikon Switzer

31、land was used to visualize the behaviour of the potatoes in the transparent duct and to measure the time interval between consecutive potatoes A sheet with a coordinate system was placed behind the opening of the duct the X axis representing the ground level Time was registered when the midpoint of

32、a potato passed the ground line Standard deviation of the time interval between consecutive potatoes was used as measure for plant spacing accuracyFor the measurements the camera system was set to a recording rate of 1000 frames per second With an average free fall velocity of 25ms-1 the potato move

33、s approx 25mm between two frames sufciently small to allow an accurate placement registrationThe feeding rates for the test of the effect of the speed of the belt were set at 300 400 and 500 potatoes min-1 fpot 5 67 and 83s-1 corresponding to belt speeds of 033 045 and 056ms-1 These speeds would be

34、typical for belts with 3 2 and 1 rows of cups respectively A xed feeding rate of 400 potatoes min-1 cup-belt speed of 045ms-1 was used to assess the effect of the potato shapeFor the assessment of a normal distribution of the time intervals 30 potatoes in ve repetitions were used In the other tests

35、20 potatoes in three repetitions were used24 Statistical analysisThe hypotheses were tested using the Fisher test as analysis showed that populations were normally dis-tributed The one-sided upper tail Fisher test was used and a was set to 5 representing the probability of a type 1 error where a tru

36、e null hypothesis is incorrectly rejected The condence interval is equal to 100-a 3 Results and discussion31 Cup-belt speedThe measured time intervals between consecutive potatoes touching ground showed a normal distribution Standard deviations s for feeding rates 300 400 and 500 potatoes min-1 were

37、 330 205 and 127ms respectively According to the F-test the differences between feeding rates were signicant The normal distributions for all three feeding rates are shown in Fig 4 The accuracy of the planter is increasing with the cup-belt speed with CVs of 86 71 and 55 respectively32 Results predi

38、cted by the modelFigure 5 shows the effect of the belt speed on the time needed to create a certain opening A linear relationship was found between cup-belt speed and the accuracy of the deposition of the potatoes expressed as deviation from the time interval The shorter the time needed for creating

39、 the opening the smaller the deviations Results of these calculations are given in Table 2The speed of the cup turning away from the duct wall is important Instead of a higher belt speed an increase of the cups circumferential speed can be achieved by decreasing the radius of the roller The radius o

40、f the roller used in the test is 0055m typical for these planters It was calculated what the radius of the roller had to be for lower belt speeds in order to reach the same circumferential speed of the tip of the cup as found for the highest belt speed This resulted in a radius of 0025m for 300 pota

41、toes min-1 and of 0041m for 400 potatoes min-1 Compared to this outcome a linear trend line based on the results of the laboratory measurements predicts a imum performance at a radius of around 0020mThe mathematical model Eqn 5 predicted a linear relationship between the radius of the roller for r40

42、01m and the accuracy of the deposition of the potatoes The model was used to estimate standard deviations for different radii at a feeding rate of 300 potatoes min-1 The results are given in Fig 6 showing that the model predicts a more gradual decrease in accuracy in comparison with the measured dat

43、a A radius of 0025m which is probably the smallest radius technically possible should have given a decrease in standard deviation of about 75 compared to the original radius4 ConclusionsThe mathematical model simulating the movement of the potatoes at the time of their release from the cup-belt was

44、a very useful tool leading to the hypotheses to be tested and to design the laboratory test-rig Both the model and the laboratory test showed that the higher the speed of the belt the more uniform the deposition of the potatoes at zero horizontal velocity This was due to the fact that the opening al

45、lowing the potato to drop is created quicker This leaves less effect of shape of the potato and the positioning of the potato on the cup A relationship with the belt speed wasfound So to provide more room for reductions in the cup-belt speeds while keeping a high planting accuracy it is recommended

46、to decrease the radius of the roller till as low as technically possibleThis study showed that the accuracy of planting distance in the seeding furrow is inuenced for a large part by the cup-belt unit of the planterA more regular shape lower shape factor does not automatically result in a higher acc

47、uracy A sphere golf ball in most cases was deposited with a lower accuracy than a potato This was caused by the shapes of the guiding duct and cupsIt is recommended to redesign the geometry of the cups and duct and to do this in combination with a smaller roller马铃薯播种机的性能评估原文来源H BuitenwerfWB Hoogmoed

48、PLerink and J MüllerAssement of the Behavior of Potato in a Cup-belt Planter Biosytems Engineering Volume 95 Issue September 2006 3541大多数马铃薯播种机都是通过勺型输送链对马铃薯种子进行输送和投放当种植精度只停留在一个可接受水平的时候这个过程的容量就相当低主要的限制因素是输送带的速度以及取薯勺的数量和位置假设出现种植距离的偏差是因为偏离了统一的种植距离这主要原因是升运链式马铃薯播种机的构造造成的一个理论的模型被建立来确定均匀安置的马铃薯的原始偏差这个模

49、型计算出两个连续的马铃薯触地的时间间隔当谈到模型的结论时提出了两种假设一种假设和链条速度有关另一种假设和马铃薯的形状有关为了验证这两种假设特地在实验室安装了一个种植机同时安装一个高速摄像机来测量两个连续的马铃薯在到达土壤表层时的时间间隔以及马铃薯的运动方式结果显示a输送带的速度越大播撒的马铃薯越均匀b筛选后的马铃薯形状并不能提高播种精度主要的改良措施是减少导种管底部的开放时间改良取薯杯的设计以及其相对于导种管的位置这将允许杯带在保持较高的播种精度的同时有较大的速度变化空间1介绍说明升运链式马铃薯种植机图一是当前运用最广泛的马铃薯种植机每一个取薯勺装一块种薯从种子箱输送到传送链这条链向上运动使得

50、种薯离开种子箱到达上链轮在这一点上马铃薯种块落在下一个取薯勺的反面并局限于金属导种管内在底部输送链通过下链轮获得足够的释放空间使得种薯落入地沟里图一杯带式播种机的主要工作部件1种子箱2输送链3取薯勺4上链轮5导种管6护种壁7开沟器8下链轮轮9释放孔10地沟株距和播种精确度是评价机械性能的两个主要参数高精确度将直接导致高产以及马铃薯收获时的统一分级在荷兰的实地测量株距未发表的数据变异系数大约为20美国和加拿大早期的研究显示相对于玉米和甜菜的精密播种当变异系数高达69时其播种就精度特别低输送速度和播种精度显示出一种逆相关关系因此目前使用的升运链式种植机的每条输送带上都装备了两排取薯勺而不是一排双排

51、的取薯勺可以使输送速度加倍而且不必增加输送带的速度因此在相同的精度上具有更高的性能是可行的该研究的目的是调查造成勺型带式种植机精度低的原因并利用这方面的知识提出建议并作设计上的修改例如在输送带的速度取薯杯的形状和数量上为了便于理解建立一个模型去描述马铃薯从进入导种管到触及地面这个时间段内的运动过程因此马铃薯在地沟的运动情况就不在考虑之列由于物理因素对农业设备的强烈影响 Kutzbach 1989 通常要将马铃薯的形状考虑进模型中两种零假设被提出来了1播种精度和输送带速度无关2播种精度和筛选后的种薯形状尤其是尺寸无关这两种假设都通过了理论模型以及实验室论证的测试2材料及方法 播种材料几种马铃薯种

52、子如圣特阿玲达以及麻佛来都已被用于升运链式播种机测试因为它们有不同的形状特征对于种薯的处理和输送来说种薯块茎的形状无疑是一个很重要的因素许多形状特征在结合尺寸测量的过程中都能被区分出来在荷兰马铃薯的等级主要是由马铃薯的宽度和高度最大宽度和最小宽度来决定的种薯在播种机内部的整个输送过程中其长度也是一个不可无视的因素形状因子S的计算基于已经提到的三种尺寸 此处l是长度w是宽度h是高度单位mm且h w l还有球形高尔夫球其密度和马铃薯密度大致相同作为参考同是在研究中用到的马铃薯的形状特征通过表一给出表一 实验中马铃薯及高尔夫球的形状特征 品种 方形网目尺寸毫米 形状因子 圣特 2835 146 阿玲

53、达 3545 362 麻佛来 3545 168 高尔夫球 428 10022 建立数学模型数学模型的建立是为了预测升运链式播种机的播种精度和播种性能该模型考虑了滚轴的半径和速度取薯勺的尺寸和间距以及它们相对于导种管壁的位置和地沟的高度如图二模型假设马铃薯在下落的过程中并没有相对于取薯勺移动或者相对于轴转动图二模型模拟过程当取薯杯到达A点的时候模拟开始释放时间是开启一个足够大的空间让土豆顺利通过所需的时间该模型同时也计算出两个连续的马铃薯之间的时间间隔以及马铃薯到达地面自由下落的时间rc 代表链轮半径带的厚度以及取薯杯长度之和xclear 取薯勺与导种管壁之间的间距xrelease 释放的间距r

54、elease 释放角度 链轮的角速度C点地沟田间作业速度和输送带速度可设定为到达既定的作物间距的要求马铃薯离开导种管底部的频率fpot 通过如下公式计算式中vc 是勺型输送带的速度单位ms1xc 是带上两个取薯勺之间的距离单位m槽轮的角速度r单位rad s1计算如下导种管的间距必须足够大以使得马铃薯能通过并被释放xrelease是当取薯勺以一定的角度release径向通过链轮时的时间间距释放角图二按以下公式进行计算rc单位m是链轮半径链条的厚度以及取薯勺长度之和xclear单位m是取薯勺端面与导种管管壁之间的间隙当马铃薯的各种参数已确定的情况下释放马铃薯的所需角度可以通过计算得到除了形状和尺寸护种壁的马铃薯的位置也具有诀定性的作用因此这个模型区分了两种状态a释放角度o所需的时间trelease的计算公式如下当马铃薯释放后将直接落到地沟由于每个马铃薯都是在一个特定的角度释放的通常那时都有一