猕猴桃采摘机器人末端执行器设计与试验

进行了棚架式栽培模式自然生长条件下簇生猕猴桃无损采摘机器人末端执行器的研究。基于果实与果柄的分离特性,提出面向机器人的果实采摘方法和简化几何模型,进行了果实与果柄分离试验的可行性验证;基于果实采摘方法设计了从底部接近、旋转包络分离毗邻果实并抓取、向上运动分离果实的末端执行器,并试制样机,进行了现场评价试验。结果表明,采摘模型能够实现果实与果柄的分离,末端执行器解决了毗邻果实分离问题,能够实现单个果实稳定抓取、无损采摘和采后抓持,成功率达到96.0%,平均单果耗时22 s。     

苹果采摘机器人仿生机械手静力学分析与仿真

提出了一种应用于苹果采摘机器人末端执行器的仿生机械手。采用腱传动式仿生机械手取代了简单的夹具,提高了末端执行器在复杂环境中抓取苹果的适应性。建立了腱传动式机械手开环控制的驱动力和抓握力间的力学模型。仿真结果表明,在相同的驱动力下,腱传动仿生机械手的抓握力与其机构参数相关。其中,有效抓握力由手指的长度和厚度决定;抓握力的分布由各指节的长度比例决定;手指的初始张角决定了其可抓取苹果的半径范围;随着苹果半径的增大,有效抓握力将减小。摩擦力能够改善抓握力在各指节的分布,使抓握力分布均匀化,同时使有效抓握力变大。     

机械手不同抓取控制方式对番茄机械损伤的影响分析

为了分析机械手不同抓取控制方式对番茄造成的机械损伤。通过Burgers粘弹性模型描述番茄的变形特征,利用蠕变实验获得番茄样本的粘弹性参数。选择匀减速、先匀速后减速以及变减速作为3种典型的抓取控制方式,并利用一次函数、巴特沃斯幅度平方函数和指数函数3种函数曲线描述末端执行器实际抓取过程中不同抓取控制方式的速度变化。在此基础上,对番茄塑性变形进行求解,分析在抓取时间一定时,不同抓取控制方式下番茄的塑性变形规律,并以最小塑性变形为依据,确定最优的抓取策略。结果表明:抓取控制方式3为最优抓取控制方式,当抓取速度v0=1 mm/s,抓取时间t0=1 s时,产生的最小塑性变形最小,红熟前期和红熟中期番茄的最小塑性变形分别为0.002 6 mm和0.009 8 mm。以抓取控制方式3进行抓取控制实验,实验数据和理论数据的吻合度较高,决定系数R2为0.99,验证了抓取控制方式3作为最优抓取控制方式的合理性和可行性,为优化机械手抓取过程提供了参考。     

双指型农业机器人抓取球形果蔬的控制器设计

现阶段针对苹果、番茄这类球形果蔬设计的采摘机器人末端执行器大多采用相似的双指结构,但是这类采摘机器人的抓取控制方法均是一对一的研究,研发成本偏高且产品不具有通用性。阻抗控制是常用的柔顺控制方法,能够将果蔬的受力—形变等效为环境导纳模型,不同的果蔬对应不同的导纳模型,但是基本的阻抗控制框架是一致的。因此,本文分别选取偏软和偏硬的两种球形果实,通过压缩试验模拟抓取过程,得到果实受力及形变数据,并以此计算得到果实等效刚度。接着,使用BP神经网络分别对原始数据进行训练及验证,得到各层权值。然后在Simulink中建立环境导纳模型并根据不同的果实选择不同的权值,并完成阻抗控制系统的搭建。同时,根据环境导纳模型中的等效刚度估计值实现在线调整阻抗控制器刚度参数。最后通过Matlab进行仿真验证,结果表明改进后方法对于抓取苹果和番茄两种果实,期望力超调分别为2.2%和1.5%,位置控制器输出最终分别稳定在0.55 mm和4.02 mm范围内,可验证所提方法在理论上能够实现农业机器人的柔性抓取。     

基于自适应神经模糊网络的果蔬抓取力控制

运用自适应神经模糊推理系统设计了农业机器人果蔬抓取力智能控制器。以当前抓取力和滑觉传感器信号的小波变换细节系数作为控制器的输入,末端执行器两指闭合距离作为控制器的输出。基于减法聚类建立模糊推理模型,通过调整聚类半径来优选模糊规则数。给出了训练样本数据集采集方法,并应用梯度下降与最小二乘混合训练算法辨识了控制器的前件参数和结论参数。对所设计的控制器进行了实验验证,结果表明该控制器能够适应果蔬质量、表面摩擦特性等方面的差异。抓取力超调量得到了限制,最大值小于0.8 N,可以避免给抓取对象造成机械损伤。     

基于气动柔性驱动器的苹果采摘末端执行器研

设计了一种基于气动柔性驱动器的苹果采摘末端执行器：以气动柔性驱动器作为其弯曲关节,用力学分析的方法对弯曲关节及末端执行器进行建模,分析建立关节弯曲量及输出力与其内腔气体压力之间的数学关系;建立了末端执行器抓取苹果目标的数学模型。实验结果表明:该末端执行器有较大的输出力,能很好地抓持苹果,并具有很好的柔顺性。     

基于气动柔性驱动器的苹果采摘末端执行器研究

设计了一种基于气动柔性驱动器的苹果采摘末端执行器:以气动柔性驱动器作为其弯曲关节,用力学分析的方法对弯曲关节及末端执行器进行建模,分析建立关节弯曲量及输出力与其内腔气体压力之间的数学关系;建立了末端执行器抓取苹果目标的数学模型.实验结果表明:该末端执行器有较大的输出力,能很好地抓持苹果,并具有很好的柔顺性.     

猕猴桃果实相向运动采摘模式的研究

目前,国内外对于农业采摘机器人研究的关键仍是效率问题,猕猴桃果实的采摘模式决定了采摘机器人末端执行器的结构形式和工作原理,同时也决定了作业效率。现阶段的果蔬采摘机器人,大都是单个果实包络抓取,然后旋转折断或者切断实现采摘。猕猴桃单个果实抓取旋转采摘时间是22s,其实抓取果实到释放可以简化为一步采摘,对于猕猴桃的采摘作业可以抛弃用手指去夹持猕猴桃的动作。为此,提出了一种上行机构和下行机构相向运动的采摘模式,并采用正交试验以采摘力为评价指标研究了该采摘模式。结果表明:试验因素显著性居前两位的是上行机构作用位置和下行机构行进速度,采摘成功率为96.3%,单果采摘时间约为5.3s。该采摘模式的研究为今后末端执行器的设计提供了基础和依据。     

多功能蜓爪式仿生末端执行器设计与试验

为实现利用同一机械手柔顺抓取各种形状果蔬,并且在保证抓取效率的前提下,有效避免末端执行器对果蔬的损害,设计了一种基于仿生原理的多功能蜓爪式末端执行器。首先通过体式显微镜将蜻蜓各爪指的相关物理信息转换为具有指导意义的数据和量化模型,并采用理论分析与数学建模的方法,确定了机械手前后爪腿节、胫节与跗节的长度分别为36、48、31 mm,机械手中爪腿节、胫节与跗节的长度分别为48、48、36 mm;在此基础上,采用D-H法建立了该欠驱动末端执行器的运动模型,绘制了机械手的包络空间区域,进而得到机械手能够完全包络各种形态果蔬的主要抓取部位;最后,应用并联机构平台和串联机构平台开展静态抓取破坏试验,测定了损伤力极限值,并进行了果蔬抓取试验。试验结果表明,仿生机械手对番茄、苹果、柿子椒和茄子的平均抓取成功率分别为90.7%、88.6%、87.9%和87.2%,损伤率分别为4.3%、0.7%、3.6%和2.1%;可见该仿生末端执行器能够较好地实现对各种形态果蔬柔顺、稳定的无损抓取。     

基于外力估计的并联机器人柔顺控制策略研究

针对并联机器人在作业过程中的位置精确控制及柔顺控制问题,提出了基于外力估计的并联机器人柔顺控制策略,实现并联机器人在作业过程中位置和力的高性能动态交互。基于外力估计的柔顺控制实现过程中,考虑到接触力传感器成本较高,提出一种无传感器外力估计的方法。首先建立并联机器人以及伺服运动系统动力学模型,利用所建立的动力学模型和电机的电流反馈值来估算外力作用时机器人关节力的变化。其次根据估算的并联机器人关节力,设计基于位置的阻抗控制,使并联机器人末端执行器与环境柔性接触,确保并联机器人的作业精准度与柔顺度。最后选取合适的阻抗控制参数,对所提出的柔顺控制策略进行仿真分析并且在搭建的实验平台上进行了实验验证,实验结果表明所提出的方法可以实现并联机器人的精确柔顺作业。     

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。