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针对负载质量和负载力等参数不确定的主动悬挂电液伺服作动器位置控制系统,采用内模控制方法对其进行位置控制。根据系统特性建立了电液伺服作动器位置控制系统线性化数学模型,并基于此模型设计了内模控制器。为验证内模控制器的控制效果,进行了与PID控制的对比仿真分析和台架试验。以阶跃信号为输入信号进行了仿真分析,仿真结果表明,系统在内模控制下的单位阶跃响应快速、平稳、无超调,动态特性优于PID控制,且当系统受到外部干扰时,内模控制比PID控制能更快速、平稳地恢复至稳态值。台架试验包括改变正弦输入信号频率和改变负载质量两种试验方案。结果表明,当正弦输入信号频率由0.1Hz增加至2Hz时,基于PID控制的系统跟踪性能明显恶化,而基于内模控制的系统跟踪性能并无明显变化;当负载质量发生变化时,基于内模控制的系统跟踪误差变化幅度明显小于PID控制。基于内模控制的电液伺服作动器位置控制系统的跟踪响应性能优于PID控制,满足主动悬挂系统的使用要求。 相似文献
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张威何锋 《农业装备与车辆工程》2023,(3):21-25
为提升纯电动汽车动力总成冷却系统温度控制效果并降低能量消耗,提出一种遗传算法（GA）优化模糊PID参数的控制方法。搭建纯电动汽车分布式冷却系统模型,将模糊控制理论与PID相结合,实时调整PID控制参数,并采用遗传算法优化模糊PID的量化因子和比例系数,建立GA-模糊PID控制器,在所制定的控制策略下调节冷却系统中电子水泵转速和风扇风速,控制冷却液进口温度,进而控制动力总成温度。通过AMESim和Simulink联合仿真,结果表明,相比阈值控制和PID控制,GA-模糊PID控制具有良好的温度控制能力和节能效果。 相似文献
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为解决传统农业温控系统存在的大惯性、时变非线性和纯滞后性问题,以恒温水浴温度调控系统为研究对象,建立温度调控机构的一阶加纯滞后数学模型。充分考虑PID控制、模糊控制与灰色预测控制各自的优点,仿真评估灰色预测算法预测系统温度的相对残差均值为4.73×10-6,方差比为0.001 8,反映出模型预测的可靠性很高;设计将模糊PID作为主控制器,灰色预测算法作为辅助控制器的协同温度控制模型。仿真试验结果表明：灰色预测—模糊PID控制器的超调量相对于传统PID控制器下降0.35%,相对于模糊PID控制器下降0.18%;灰色预测—模糊PID控制器的调节时间相对于传统PID控制器缩短232.8 ms,相对于模糊PID控制器缩短204.9 ms;灰色预测—模糊PID控制器的稳定温度值相对于传统PID控制器减小3×10-3℃,相对于模糊PID控制器没有发生变化;对于相同的扰动信号,灰色预测—模糊PID控制器的调节时间相对于传统PID控制器缩短252.3 ms,相对于模糊PID控制器缩短248.2 ms。灰色预测与模糊PID的恒温水浴协同温度控制与传统PID、模... 相似文献
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基于改进B样条神经网络-PID控制器的温室温度控制技术 总被引：1，自引：0，他引：1
针对温室温度控制系统所存在的大惯性、非线性等问题,提出神经网络PID控制算法,并利用知识局部存储且具有较快学习速度的B样条函数作为网络隐层神经元函数,同时,提出了β参数型-B样条曲线的重新参数化方法,通过学习算法对β参数搜索来动态调节B样条基函数,从而建立B-BP神经网络,并利用其对PID控制器的比例、积分和微分参数进行优化调整,从而为B-BP-PID控制器的参数自适应调整提供更好的保证,使温度控制系统有效跟踪系统模型并达到较高的辨识精度。仿真试验获得B-BP-PID控制器的最佳β因子为3.2,其温度控制超调量为27%,调节时间为0.8 s,而BP-PID控制器的超调量为25%,调节时间为4.8 s,RBF-PID控制器的超调量为40%,调节时间为1.2 s,新算法有效提高了温度控制过程的稳定性、精确性与鲁棒性。 相似文献
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《农业装备与车辆工程》2016,(4)
随着汽车电子技术的发展,主动前轮转向系统作为一项新技术越来越受到人们的关注。本文设计了一种主动前轮转向系统的PID参数自调整模糊控制器。首先,建立了汽车动力学模型,设计了AFS模糊控制器的控制策略,然后设计主动前轮转向系统模糊控器仿真模型图,利用Matlab/Simulink软件进行前横摆角速度模糊控制的仿真,从而实现横摆角速度模糊控制。结果表明:由于PID参数自调整模糊控制器的设计,车辆的操纵稳定性和瞬态响应性能都有明显提高。 相似文献
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基于BP神经网络的PID控制在温室控制系统中的应用 总被引：1，自引：0，他引：1
以温度参数控制为例,结合传统PID控制规律,利用BP神经网络完成温室温度控制系统的PID控制系统设计.通过阐述基于BP神经网络的PID控制算法,完成温度控制系统中的BP神经网络PID控制参数在线整定.采用MATLAB对基于BP网络的PID温度控制系统进行了仿真,结果表明,PID控制算法能够实现控制参数的自适应调整,使系统对输入的响应达到小误差. 相似文献
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针对底盘测功机控制系统在动态控制方面延迟较高和误差大的问题,提出一种基于RBF(径向基函数)神经网络的底盘测功机控制策略。通过对比分析汽车实际运行工况与底盘测功机加载工况的动力学特征,建立了底盘测功机输出力加载模型。基于电涡流测功机的加载力输出特性设计了控制系统框架和RBF神经网络控制器。通过MATLAB中的S-function函数语言编写了控制策略,且在DCG-10E型底盘测功机上进行了硬件在环试验。对比PID控制下的加载力输出曲线,结果表明,输出力上升过程稳定且快速。本文验证了在底盘测功机上应用RBF神经网络PID控制策略的可行性。 相似文献
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Overland water and salt flows in a set of rice paddies 总被引：1，自引：0，他引：1
E. Playn O. Prez-Coveta A. Martínez-Cob J. Herrero P. García-Navarro B. Latorre P. Brufau J. Garcs 《Agricultural Water Management》2008,95(6):645-658
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. 相似文献
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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。 相似文献
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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。 相似文献
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对《种子法》存在问题的探讨 总被引：1，自引：0，他引：1
李鹏 《农业机械化与电气化》2011,(6):129-130
《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。 相似文献
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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. 相似文献
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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。 相似文献
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Gunter Wriedt Marijn van der Velde Alberto Aloe Fayçal Bouraoui 《Agricultural Water Management》2009,96(5):771-789
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. 相似文献
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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。 相似文献
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车辆ABS控制算法的研究及探讨 总被引：1，自引：0，他引：1
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。 相似文献