钵苗移栽机器人控制系统设计研究

钵苗移栽是温室穴盘育苗生产中的重要环节。为实现穴盘钵苗智能化移栽作业,设计了一种高速钵苗移栽机器人。该机器人主要由穴盘定位输送系统和平动二自由度钵苗移栽系统构成,基于准确定位抓取、快速移动栽植的作业要求和系统工作原理,以PLC为核心,结合传感器和伺服控制技术对移栽机器人运动控制系统进行了设计。控制系统首先基于穴盘钵苗位置坐标信息,规划出取苗爪移栽路径;然后根据并联机构运动学逆解模型,对并联机构两主动关节伺服驱动电机的转动规律进行控制,并通过系统间的运动协调,实现钵苗从高密度盘到低密度盘或营养钵的连续高速移栽作业。以育苗期28天、钵体含水率为60%左右的黄瓜苗为对象,在移栽动平台最大加速度为45m/s2、移栽频率为45次/min的条件下,进行128孔穴盘到50孔穴盘的连续钵苗移栽运行试验。试验表明,该钵苗移栽机器人控制系统设计合理,系统间运动协调可靠,移栽成功率平均达91.4%,单爪移栽速率可达2 700株/h,满足了自动化移栽作业要求。     

基于Delta并联机构钵苗移栽机器人尺度综合与轨迹规划

Delta并联机构具有速度快、运动精度高、灵活性强等特点,非常适合穴盘育苗过程中的移钵作业及补苗需要。基于三自由度Delta并联机构和气动取苗爪,设计了一种高速钵苗移栽机器人。通过建立Delta并联机构的单支链约束方程,求解出钵苗移栽机器人的可达工作空间;为使其可达工作空间尽可能接近设计工作空间,以机构雅可比矩阵条件数作为惩罚条件,建立起兼顾钵苗移栽机器人整机尺寸与运动学性能的尺度综合目标函数,并应用遗传算法得到机构最优尺寸参数。根据盘到盘钵苗移栽的运动要求,对移栽轨迹进行规划并选取五次多项式作为移栽动平台的运动规律函数。基于机构尺度综合和轨迹规划设计物理样机,并进行盘到盘的钵苗移栽和健壮苗补苗性能试验,结果表明:随着移栽动平台携苗运动最大加速度的提高,钵土破碎率逐渐加大,钵苗移栽合格率逐渐降低,在最大加速度amax为30 m/s2时,钵苗移栽合格率可达95.5%,移栽速率可达2 149株/h,在此加速度下进行健壮苗补苗试验,补苗合格率可达92%,证明了将Delta并联机构用于钵苗移栽机器人的可行性,以及尺度综合和轨迹规划的合理性。     

自动移栽机整排取苗间隔投苗控制系统设计与试验

针对自动移栽机取苗控制精度、协调配合等问题,结合自主设计的自动移栽机取苗、投苗及分苗系统结构及其工作原理,基于可编程控制器PLC设计了一种整排取苗间隔投苗控制系统。该控制系统采用3个行程开关I1、I2、I3检测翻转取苗状态,实现取苗爪针在插入苗钵过程中逐渐收缩的过程,减少了对钵体内部的损伤;运用光电传感器感应分苗杯位置和数量,以增量式编码器获取分苗杯运动位移,通过两者配合完成苗钵在最佳投苗点投苗;选用72孔和128孔穴盘、20 d苗龄的黄瓜苗进行取苗、投苗栽植试验,检测控制系统性能。试验结果表明:在栽植频率40~70株/min范围内,两种穴盘苗的取苗投苗综合成功率均高于95%,平均值为97.98%,随着栽植频率的增加,取苗投苗综合成功率有所下降,但变化不大,证明设计的控制系统能适用不同规格苗盘、不同栽植频率下的自动移栽,达到高效自动移栽目的。     

蔬菜移栽夹茎式取苗装置设计与试验

针对半自动移栽机作业效率低、作业质量差的问题，设计了一种面向蔬菜移栽机器人的夹茎式自动取苗装置。取苗装置经过整排取苗、等距分苗、精准投苗，可实现高效、高质自动化取投苗作业。建立多级剪叉分苗机构与夹苗装置的运动力学模型，对钵苗下落运动、气动系统进行模型设计及分析计算，搭建取苗试验装置。试验选取穴盘辣椒苗作为研究对象，以钵苗苗龄、基质含水率、取苗频率为试验因素，设计以取苗成功率、基质破碎率为评价指标的单因素试验。根据试验结果，采用Box-Behnken响应曲面分析法设计正交试验，探究了苗龄与基质含水率、苗龄与取苗频率及基质含水率与取苗频率之间的交互作用对取苗效果的影响，优化取苗参数。试验结果表明，当苗龄33 d、钵苗基质含水率46%、取苗频率75株/min时，取苗成功率为97.36%,基质破碎5.07%,可满足大田自动化移栽的取苗及投苗要求。     

基于EDEM-RecurDyn的指夹式取苗爪仿真优化与试验

为了实现自动移栽机高效、高质量取苗,提出整排取苗、同时投苗的工作方式。以指夹式取苗爪为研究对象,阐述了取苗爪的结构组成及工作原理。建立了取苗爪的运动数学模型,结合钵体力学特性及根系分布特点,对组成取苗爪的各构件进行尺寸参数优选,并在RecurDyn中建立其虚拟样机模型。通过试验进行钵体力学性能测量,对试验所得数据进行处理,得出钵体物理特性参数,进而在EDEM中建立钵体颗粒模型。通过EDEM-RecurDyn耦合仿真取苗爪插入、夹取、提离过程。分析取苗爪插入钵体苗深度、开始夹苗深度对取苗时钵体的影响,仿真优化得到当取苗爪插入钵体深度I_d=34 mm,插入钵体平均速度I_v=280 mm/s,开始夹苗深度C_i=4 mm,夹苗平均速度C_v=250 mm/s时,可以获得较好的钵体完整性。在16、20、24次/min的取苗速率下进行取苗爪取投苗试验,结果表明,所设计的指夹式取苗爪取苗成功率均在96%以上,钵体破碎率小于1%,具有良好的取苗、投苗效果,在取苗作业中可以保持良好的钵体完整性。     

温室穴盘钵苗成排取苗移植手部件设计与试验

温室穴盘钵苗成苗后需要从穴盘移植到培养槽孔,但因人工作业效率低,限制了其规模化生产。为实现高效、高质量自动化移栽作业,本文设计一种用于温室穴盘钵苗高速取、放苗移栽作业的爪片插入式成排移植手部件,分析取苗作业过程移植手的受力及取放苗过程移植手的变形,结合ADAMS刚柔耦合仿真试验开展植苗手优化设计,确定爪片尖点拟合曲线及移植手抓取穴盘钵苗的运行轨迹。以移植手取苗深度、基质含水率、升降速度和水平横移速度为试验因素,开展成排移植手部件取、放苗正交试验,并确定最佳参数组合。结果表明,当取苗深度48mm、基质含水率69.9%、升降速度0.24m/s和水平横移速度0.35m/s时,取放苗成功率为97.9%,效率10322株/h,满足高速、高效移栽要求。该研究为温室穴盘钵苗高速移栽部件的国产化开发提供参考。     

一体式蔬菜钵苗取苗爪夹持力检测传感器设计与试验

针对入钵夹取式全自动蔬菜钵苗移栽机取苗爪体积小，夹持力检测传感器结构与安装方式干涉取苗爪正常取投动作、影响自身精度与使用寿命等问题，本文选用聚二甲基硅氧烷(Polydimethylsiloxane, PDMS)薄膜作为传感器介电层，设计了一种内置式钵苗夹持力传感器，并通过嵌入方式实现取苗爪与传感器一体化设计。建立穴孔、钵体基质、取苗爪仿真模型，应用LS-PrePost软件对取苗过程进行耦合仿真，得到取苗爪与钵体基质接触部位最大受力区域，确定了取苗爪与传感器的结构与尺寸；设计夹持力信号检测系统，将硬件电路与采集软件结合，完成电容量-电压转换、信号放大、噪声滤除，实现夹持力信号的采集、处理、显示与保存等功能。为验证传感器性能，进行传感器标定试验与室内验证试验。标定试验表明，在不同振荡频率下，夹持力传感器平均灵敏度为0.372 8 N/V,平均线性决定系数为0.989 2,精度为7.548%,量程为7 N,满足移栽过程中夹持力检测的准确度要求；室内验证试验表明，夹持力检测传感器具有良好的稳定性与适应性，可用于移栽机取苗机构夹持实时精准检测。     

基于LabVIEW的自动移栽机整排取投苗控制系统设计

针对目前半自动移栽机作业效率低、控制系统性能不稳定等问题,提出一种整排取苗、双接苗带投苗的取投方案,并设计开发了控制系统。工作时,双苗盘每次进给一排,使钵苗到达取苗位,取苗机械手整排取苗后输送到放苗位;机械手放苗,钵苗进入接苗带栅格中,接苗带转动投苗。系统采用PC机作为上位机,由LabVIEW构建控制系统操作界面;PLC作为下位机,接受传感器的检测信号和上位机发送的指令信号,通过控制步进电机和气缸协同工作来完成整排穴盘苗的取投。试验表明:实时操作上位机可以控制系统的运行,监测机械手运动位置和取投苗过程,实现了整排穴盘苗取投过程的监视与控制。     

烟草钵苗移栽机成穴机构的运动学仿真分析

吊篮式烟草钵苗移栽机成穴机构的作业性能直接影响移栽机的移栽质量。为了探讨成穴机构各杆件相互作用及成穴铲运动规律,针对成穴机构进行简化,建立矢量方程得到成穴机构成穴铲的位移、速度和加速度模型。采用ADAMS软件建立成穴机构的三维运动仿真模型进行仿真分析,对获得成穴铲竖直和水平方向的位移、速度及加速度变化曲线进行分析,满足成穴要求,验证了成穴机构结构设计的合理性,为烟草钵苗移栽机成穴机构的运动轨迹进一步优化及动力学仿真分析提供了理论依据。     

轻便型温室换盘移栽机设计与试验

针对国内中小型温室的实际生产需要,设计了一种轻便型温室换盘移栽机,提出了多爪间隔定距取放苗方案,从而大大简化了传统含爪距扩展的多爪取放、输送系统。同时,提出了源盘与目标盘的长距链传动推杆输送结构,取代了传统三伺服的喂盘取盘短距链传动与长距带组合结构,在实现结构轻量化的同时,有效提高了穴盘输送的定位精度。整机控制系统实现高度集成化,使用了模块化的软件设计,减少了被控对象和控制流程,并降低了整机功耗。试验结果表明:源穴盘换行作业平均误差0.25mm,换盘作业平均误差0.89mm;目标穴盘换行作业平均误差0.31mm,换盘作业平均误差1.09mm;多爪取放苗机构可高效完成取苗栽苗作业,水平输送机构以1.5m/s驱动多爪取放苗机构高速稳定的往复运动。该机的研制为各类温室育苗的移栽作业提供了装备支撑。     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

A European irrigation map for spatially distributed agricultural modelling

We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.     

粉质仪和拉伸仪在面粉生产中的应用

在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。     

农村信息化服务的现状及建设措施

分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。     

车辆ABS控制算法的研究及探讨

对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。