粮仓窗户远程自动控制系统设计     

周林泉 《粮食储藏》2011,40(1):24-25

设计出一种粮仓窗户远程自动控制系统。根据仓内外的温度和湿度变化,自动开启或关闭窗户及通风机械,实现粮仓的自动通风,自动控制。该系统可与粮情检测系统、通风控制系统等结合,组成粮仓自动化管理系统。  相似文献   

The power-supply of X-ray machine adopting PID control and high-frequency inverter technology     

ZHANG Si-jie  ZHAO Xiao-yu  ZENG Xiao-ping  PENG Cheng-ling  GUO Xing-ming  SHI Ling 《保鲜与加工》2011,(5):130-134

To solve the problem of low control accuracy and low stability of current X-ray machines, a kind of digital power supply for X-ray machine is introduced. In the digital power supply, some key technologies are used to improve the output stability of the high frequency inverter, including improved BUCK circuit for voltage regulating circuit, high frequency inverter and soft switching technology for the high-voltage generator. The PWM control technology is used to control the switch transistor of voltage regulating circuit and inverter circuit, which makes the drive waveform output stable and easy to control. In order to improve the control accuracy, reduce the volume and change high voltage consecutively, the software PID of the microcomputer is used to control the feedback circuit. The high-accuracy power chip is used for the filament power supply to make the filament electric current stable. Through the analysis of the circuit, the parameters of the circuit are calculated and the circuit is simulated by PSPICE software. The results show that the theoretical analysis is consistent with the practical simulation results. The design can meet the requirement of the technology indices of the power supply of the X-ray machines.  相似文献   

Landscape irrigation scheduling efficiency and adequacy by various control technologies   总被引：1，自引：0，他引：1  

M.S. McCreadyM.D. Dukes 《Agricultural Water Management》2011,98(4):697-704

Automated residential irrigation systems tend to result in higher water use than non-automated systems. Increasing the scheduling efficiency of an automated irrigation system provides the opportunity to conserve water resources while maintaining good landscape quality. Control technologies available for reducing over-irrigation include evapotranspiration (ET) based controllers, soil moisture sensor (SMS) controllers, and rain sensors (RS). The purpose of this research was to evaluate the capability of these control technologies to schedule irrigation compared to a soil water balance model based on the Irrigation Association (IA) Smart Water Application Technologies (SWAT) testing protocol. Irrigation adequacy and scheduling efficiency were calculated in 30-day running totals to determine the amount of over- or under-irrigation for each control technology based on the IA SWAT testing protocol. A time-based treatment with irrigation 2 days/week and no rain sensor (NRS) was established as a comparison. In general, the irrigation adequacy ratings (measure of under-irrigation) for the treatments were higher during the fall months of testing than the spring months due to lower ET resulting in lower irrigation demand. Scheduling efficiency values (measure of over-irrigation) decreased for all treatments when rainfall increased. During the rainy period of this testing, total rainfall was almost double reference evapotranspiration (ET_o) while in the remaining three testing periods the opposite was true. The 30-day irrigation adequacy values, considering all treatments, varied during the testing periods by 0-68 percentile points. Looking at only one 30-day testing period, as is done in the IA SWAT testing protocol, will not fully capture the performance of an irrigation controller. Scheduling efficiency alone was not a good indicator of controller performance. The amount of water applied and the timing of application were both important to maintaining acceptable turfgrass quality and receiving good irrigation adequacy and scheduling efficiency scores.  相似文献   

汽车发电机定子铁芯卷叠生产线自动控制系统的研制     

徐慧贞  吴开禾  庄表微  陈陵 《福建农林大学学报(自然科学版)》1990,(3)

汽车发电机定子铁芯卷叠新工艺生产线自动控制系统由自行设计的专用微机和日本三菱F—60可编程序控制器组成。以 Z80 CPU 为核心的专用微机具有计数带料长度、厚度实时检测及根据带料厚度变化自动决定带料长度等功能。F—60可编程序控制器能完成从带料至加工成定子铁芯成品整个工艺过程的自动控制,实现了高速冲裁机、卷绕专机之间及其与其它各台专机之间的协调控制,系统自动化程度高,控制灵敏、可靠。  相似文献   

模糊控制技术在太阳热水系统工程中的应用     

马敏  雷廷宙  王磊  高林朝  张炜宇 《河南农业大学学报》2003,37(2):192-195,204

介绍了太阳热水系统工程的基本组成及特点，详细阐述了采用PIC系列单片机和模糊逻辑控制算法实现水温恒定控制的基本原理、电路设计、精确量的模糊化、模糊控制规则以及测控软件的编制。  相似文献   

基于不同模糊算子的模糊推理方法及效果分析     

李仁杰  刘峰  辛明影  张利芬 《东北农业大学学报》2002,33(1):90-95

给出了基于不同模糊算子的模糊推理方法 ,简单地介绍了模糊控制器的基本结构 ,比较分析了基于不同模糊算子的模糊推理方法的推理结果和计算机控制仿真效果  相似文献   

一种单稳型环形振荡器的提出及其应用     

卢容德 《长江大学学报》2007,4(4):75-78

提出了单稳型环形振荡器的原理和电路,用Multisim8仿真软件进行了电路仿真,介绍了单稳型环形振荡器的应用,讨论了集成74121单稳态触发器定时元件RC对暂稳时间的影响。按照交通灯控制信号的要求,安装调试了单稳型环形振荡器及控制信号产生电路。  相似文献   

西洋参干制微机检控系统的研究     

郭文川  国培光  朱新华 《西北农林科技大学学报(自然科学版)》1997,25(2):81-84

在分析微机应用技术和西洋参人工干制现状的基础上，对西洋参干制过程微机检控系统进行了研究。建立了控制对象的数学模型，并依据自动控制原理和仿真技术确定了控制算法，对检控系统的电路和程序进行了设计、安装和调试。该系统能自动跟踪最佳的温度变化曲线，测量误差＜０．２５℃，控制误差＜０．５℃，测量温度范围０～１００℃。  相似文献   

油田污水处理自动加药控制器的设计     

翁惠辉  魏灵芝  程南 《长江大学学报》2007,4(1):71-73

以油田污水处理站为背景,研究污水处理过程中PPM控制问题。通过对油田污水处理过程控制原理的阐述和对自动控制系统结构模型的深入剖析,结合系统控制策略,建立了PPM加药控制模型。在此基础上,论述了基于PI算法的控制器设计。仿真试验结果表明,PPM加药控制方法可以中和系统离子浓度的变化,达到跟踪误差小,调节时间短等性能指标。  相似文献   

基于MC68376单片机的柴油机电控技术的试验研究     

郑培  陈慧岩 《中国农业大学学报》2003,8(6):54-57,68

对国内外柴油机电控技术的发展态势进行了分析，阐述了柴油机燃油喷射位置式PID电子控制方法的原理。对基于MC68376单片机的柴油机燃油喷射电控系统的组成及其功能进行了研究。针对BF8L413F柴油机和BOSCH-P8AE喷油泵调速系统的特点，分析了进气压力和温度，及燃油温度对电控柴油机性能的影响。台架试验结果表明。增加进气压力和温度，及燃油温度等控制参数后，改善了电控柴油机的整体性能，能够满足实际车辆的使用要求。  相似文献