水肥一体化施肥机EC和pH改进自抗扰解耦控制

针对水肥一体化施肥机控制系统在交叉耦合、内外不确定条件下难以通过建立精确数学模型进行跟踪控制的问题,提出一种EC和pH改进自抗扰解耦控制策略。利用六次多项式曲线拟合对系统阶跃响应数据进行滤波处理,由面积法构建系统简化数学模型。选择静态解耦法实现系统解耦,对分解后的两个子系统分别设计自抗扰控制器并进行改进,给非线性状态误差反馈率添加类积分项,并引入模糊控制理论实现其参数在线自整定。仿真结果表明,系统EC和pH的调节时间分别为44 s和39 s,超调量分别为5.5%和0.3%,输出绝对误差分别小于0.1 mS/cm和0.2,该控制器能够实现系统高精度独立调节,相比于线性自抗扰和PID控制器,响应速度更快,抗干扰能力和鲁棒性更强。试验结果表明,该控制器调节误差与仿真结果吻合,并且能够使系统用水量、用肥量、用工量分别降低33.13%、35.75%、35.01%,作物产量提升15.16%,节水、节肥、节工和增产效果显著,具有很高的可行性。     

切削加工机器人刚度模型研究

通过对机器人臂杆的分析研究,把机器人臂杆当作一个柔性杆进行处理,分别求出其拉伸、扭转和弯曲的挠度,运用误差参数建立运动学模型,从而求得臂杆末端挠度的映射模型,并结合机器人各关节传动误差在机器人操作末端上的挠度误差映射,最终在机器人操作末端叠加关节挠度和臂杆挠度,通过刚度的定义求解出机器人总的操作空间刚度。建立的机器人刚度模型可为机器人切削加工过程中刀具的误差补偿提供依据。     

基于DRNN网络的风力辅助提水机自整定PID控制

基于风力机和离心水泵的特点,提出了一种风力辅助提水机结构及该机的控制系统。该机是一个耦合的两输入两输出时变系统,系统存在的响应较慢,负荷的随机变化及参数快时变的特性。固定参数PID控制难以适应此系统控制要求,因此,提出一种基于回归神经网络（DRNN）的两输入两输出PID控制器结构,给出了DRNN神经网络参数学习算法和PID控制器参数自整定算法。使该系统能在自然界的风速随机变化的情况下使风力机最大可能利用风能,同时与离心水泵输出功率匹配.计算机仿真结果验证了该控制策略可行性,这为以后进一步研究奠定了基础。     

利用速率陀螺对挠性操纵器进行有效振动控制

利用安装在挠性臂末端的速率陀螺发出的反馈信号，实现了挠性臂末端的位置控制。卡尔曼恩滤波器判断出控制状态反馈的状态变量。卡尔曼恩滤波器和状态反馈增益是由最佳检测来确定的。检测的根据是由挠性臂系统几何数据和电数据而定的参数。同时进行了模拟和实验，并证明了速率陀螺的设置明显地改善了其性能。     

迭代反馈整定在电液伺服系统中的应用

迭代反馈整定（IFT）控制方法能够在未知系统模型的前提下,完成系统控制器的参数整定,使系统控制性能趋向优化。迭代反馈整定方法与传统PID控制器相结合,构成一种IFT—PID控制器,该控制器能够实现在线自整定。将该控制器应用到电液伺服系统中,结果表明,即使被控系统存在很强的非线性,该控制器也能够在外界扰动和系统工况发生变化时,完成控制器参数整定,使控制系统取得满意的控制效果。     

双金属带传动无级变速器设计与仿真

为进一步提高金属带CVT转矩承载能力,扩大CVT的应用范围,设计了一种双金属带式CVT。分析了双金属带CVT的运动及动力学传动特性及变速器传动效率;建立了液压控制系统简化数学模型并分析了系统稳定性;建立了基于某车型的双金属带无级变速器AMEsim整车仿真模型并进行了PID参数整定。结果表明：设计的液压系统较好解决了速比同步控制问题并具有良好的速比控制精度,与单金属带CVT相比,可实现相同带轮夹紧力条件下变速器转矩承载能力倍增,验证了该结构CVT及液压控制系统的可行性。     

喷头仰角调节机构的研制及其对喷头性能的影响

为使旋转式喷头更广泛地适应生产发展的需要,改变喷头结构形式,在喷头的空心轴与喷体间采用变截面平面铰接,对旋转式喷头主喷管仰角在0°~30°间连续调节,达到对旋转式喷头仰角调节的目的.室内试验表明:该仰角调节方式对单喷头水力性能影响明显,喷头的射程发生了明显的变化,减幅达15.6%;同时喷头的水量分布也由三角形变为长方形,且喷头末端的水量明显增加.室外有风条件下喷头组合测试显示,经适当的组合,能够减少风对喷灌系统的影响,提高喷灌系统的适用性.     

永磁交流调速系统参数辨识与PI自整定研究

传统PI控制器不具有参数在线整定功能,难以满足高性能永磁交流调速系统要求。根据永磁同步电机速度环等效原理和经典控制理论推导出PI参数与永磁电动机转动惯量的数学关系;根据永磁同步电机的运动方程和离散模型参考自适应理论,建立永磁电动机转动惯量辨识模型;通过软件方式实现PI参数在线自整定。基于TMS320F2407A的全数字交流调速实验结果证明离散模型参考自适应理论可实现转动惯量的在线辨识,PI自整定可有效地消除系统的超调,减少响应时间,极大地提高了系统的动态性能。     

风力发电变频水泵智能控制策略研究

针对风力发电机和逆变器的特点,给出了风能变频水泵的两输入两输出耦合系统时变模型结构。保持逆变器输入电压恒定的前提下,扰动逆变器输出交流电的频率来实现风力发电机的最大功率跟踪。根据解耦和神经网络的思想,采用两个回归神经网络（DRNN）在线调整两个PID控制器的参数,一个神经元解耦补偿器完成系统的解耦,实现了不依赖于对象模型的自适应PID解耦控制。计算机仿真结果验证了该控制策略可行性,这为以后进一步研究奠定了基础。      

异步电动机调速系统自适应辨识的CMAC-ADRC算法

针对异步电动机调速系统快速响应时启动超调量大的问题,提出了一种基于自适应参数辨识的小脑模型神经网络复合自抗扰控制(CMAC-ADRC)的控制算法。将CMAC与ADRC各自的优点相结合,利用CMAC神经网络实现前馈控制,通过在线学习来抑制系统的超调量,增强系统的鲁棒性能,提高系统的快速性能,利用ADRC技术实现反馈控制,进一步增强系统的抗干扰能力。利用参考模型自适应参数辨识技术对转动惯量进行辨识,优化自抗扰补偿系数。以变频器结合异步电动机为控制对象,进行仿真,基于自适应参数辨识的CMAC-ADRC控制算法的干扰响应幅度是一阶优化自抗扰控制下干扰响应幅度的44.57%,是小脑模型神经网络复合比例-微分(CMACPD)控制下干扰响应幅度的17.69%,干扰恢复时间是一阶优化自抗扰控制下干扰恢复时间的50%,是CMAC-PD控制下恢复时间的60%。搭建MCU-CPLD-DSP控制平台进行了实验,基于自适应参数辨识的CMAC-ADRC控制算法的超调量是一阶优化自抗扰控制的45.49%,上升时间是一阶优化自抗扰控制的53.33%,干扰响应幅度是一阶优化自抗扰控制干扰响应幅度的71%,干扰恢复时间是一阶优化自抗扰控制干扰恢复时间的76.47%。     

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。