水田宽幅喷雾机变量控制系统研究

宽幅变量喷雾机是水稻植保作业的重要装备.为此,提出了以电动控制阀作为变量执行机构,根据流量传感器和压力传感器的反馈信号建立了闭环控制模型,从而克服了以往变量控制方式存在的结构复杂、成本高等不足.同时,利用嵌入式操作系统和PC104工控机,开发了基于RS485总线的变量作业控制系统软硬件,试验验证了上述系统的有效性和可行性.     

水稻精量旱穴直播电驱排种设计与试验

针对地轮滑移造成播种机播种不均、漏播及株距调节精度不高的问题,以水稻精量旱穴直播机为对象设计了一种电驱控制系统代替传统的地轮驱动排种。该控制系统以GPS模块(伪距单点定位)和霍尔元件两种传感器进行速度检测,分别测试了3～4km/h、4～5km/h、5～6km/h和6～7 km/h等4种作业速度下的速度值,并检测了株距为20cm时两种测速装置的播种情况。试验结果表明:霍尔传感器在低速作业下速度值更稳定;速度越高,标准差越大;作业速度在3～5km/h时两种传感器的电驱控制系统播种合格率均大于80%,符合播种作业要求。本研究为单点定位GPS模块和霍尔传感器应用于旱田农机具测速系统提供了参考。     

基于大马力精播机工况监测的田间无线调度系统

针对农机作业工况信息滞后,与农机作业规模化、集成化程度提高之间不匹配的问题,设计了以大马力精播机为主要研究对象的田间作业机工况信息采集硬件系统。在传统的作业速度和作业面积测量基础上,结合数据融合技术,降低了由于地轮打滑引起的测量误差,提高了种肥监测精度;系统增加了发动机转速与油耗的测量,为高效、经济作业提供了优化方案。系统采用基于802.11n的无线传感器网络将各工况信息进行采集,降低了系统布线难度,也为进一步实现农机作业合理调度提供了可靠数据。     

基于LabVIEW的吊杯栽植器成穴阻力试验系统设计

吊杯栽植器是吊杯式移栽机直接与土壤接触的工作部件,其形状、尺寸及作业参数直接影响栽植器打穴栽植性能和效率.为深入研究吊杯栽植器尺寸、作业参数对成穴阻力的影响,设计了一种基于LabVIEW的吊杯栽植器成穴阻力试验系统.采用直流电机作为栽植装置的动力源,并用数据采集卡、压力传感器和扭矩传感器等搭建了成穴阻力测量硬件系统,采...     

基于视觉组合的苹果作业机器人识别与定位

为实现机器人自动化采摘作业,设计了苹果作业机器人识别与定位系统.模拟人类采摘过程,采用单、双目视觉组合传感器系统,克服了现有识别与定位系统对目标到视觉传感器距离的依赖性.实现了对单、双目视觉系统的单独和组合标定,与手动测量结果相比,双目视觉系统标定后3个方向的标准偏差分别为3.4、1.2和1.2 cm.提出了基于苹果颜色、形状和位置特征的识别与定位方法,试验结果表明:当工作距离为240 cm时,双目视觉系统可以准确识别并定位所有苹果,深度方向标准差为4.9 em;当工作距离为150 cm时,双目视觉系统深度方向标准差为2.4 cm;当工作距离小于100 cm时,单目视觉传感器测量目标到传感器距离的标准偏差为1.0 cm.     

农用无人车环境感知技术发展现状及趋势分析*

传统农业随着人口老龄化、生产劳动强度大等原因导致其发展受到制约。近年来随着信息化技术、智能控制技术、传感器技术的快速发展,使得农用无人车的应用成为可能,实现传统农业向智慧农业的转变。对目前农用无人车发展情况介绍的基础上,重点阐述农用无人车环境感知技术的发展现状,对不同传感器技术的特点和应用情况进行总结,并比较分析不同传感器技术的优缺点;同时在对目前传感器信息融合技术发展情况总结分析的基础上,指出农用无人车环境感知技术的发展与应用没能够遵循精细化农业的发展方向,对于农业生产环境结构化研究欠缺。对此文章融合精细农业思想,提出作业对象结构化和作业机器传感器融合技术并重的解决策略,最后为降低成本、提高普及性,指出农用无人车的环境感知技术层可拓展性等发展趋势。     

基于无人机影像技术的小麦长势遥感监测

随着精准农业的发展,农作物长势监测越来越重要.传统的小麦长势监测主要依靠人工采样进行,作业效率低、监测范围小、耗费人力物力大.为有效提高小麦长势监测效率,引入无人机影像技术,以曹妃甸地区的小麦为研究对象,利用无人机影像技术和高光谱影像采集传感器完成对曹妃甸地区小麦叶面积指数、叶片生物量、叶绿素含量及叶片氮含量等长势参数...     

基于超声波传感器的小麦追肥精准评估系统研究

针对小麦追肥作业过程中开沟器易损苗伤根、追肥位置准确性无法评估的问题,基于超声波传感器设计了小麦追肥精准评估系统,提出一种基于超声波传感器阵列交叉探测小麦追肥行的方法,实时评估追肥机具作业精度。系统由作业轨迹检测部分、数据采集部分和数据分析评估部分组成,依靠安装在追肥机具上的超声波传感器交叉扫描小麦追肥行,检测追肥机具作业轨迹。采集器实时采集超声波传感器数据,记录追肥机具作业轨迹,采用阈值滤波算法对异常数据进行筛选和剔除,利用卡尔曼滤波算法最优估计当前时刻电压,根据目标电压和最优估计电压计算追肥机具偏移距离,进行追肥机具作业精度评估。田间试验结果表明：追肥机具作业速度为3~4km/h时,评估系统能够准确检测出追肥机具作业精度,偏移误判率为9%,最大误差距离为3.15cm,误差距离在2cm之内的占比超过90%,标准差均值为2.10cm,与实际作业情况相符。本评估系统可以实现在小麦追肥作业过程中,实时对追肥机具作业精度量化评估,为小麦精准对行追肥作业精度评价提供了一种新的测量手段。     

真实载荷驱动下挖掘机工作装置疲劳寿命研究

由于挖掘机挖掘作业过程中真实载荷非常复杂,提出采用试验与动力学仿真相结合的方法进行分析,以实验室现有6t小型挖掘机为研究对象,用压力传感器和位移传感器测试挖掘过程中各液压缸压力随位移的变化情况,然后把各液压缸的位移变化过程作为驱动,用ADMAS软件对挖掘过程进行动力学仿真,获得挖掘过程中工作装置各铰销点的工作载荷,再应用MSC.Fatigue软件对工作装置进行疲劳分析,获得工作装置大臂和斗杆的寿命云图,分析表明,大臂和斗杆的应力集中区域疲劳寿命最短,最小寿命计算值为13年,研究结果为工作装置结构设计提供了理论依据.     

高秆禾草履带收获机防倾翻预警系统研究

针对高秆禾草收获机在南方山坡地带作业易发生倾翻的问题,设计了防倾翻预警系统.该系统主要由上位机、控制器和传感器组成,通过倾角传感器和压力传感器共同监测,实现防倾翻预警功能.对整机质心进行了测量,测得整机质心与驱动轮轴之间的水平距离为944.5 mm、质心高度为1080.4 mm、质心与纵向中心平面的距离为27.9 mm...     

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。