【作者】 孙燕；

【导师】 曹成茂；

【作者基本信息】 安徽农业大学 ， 农业机械化工程， 2008， 硕士

【摘要】 我国淡水资源十分贫乏,而农业是用水大户,因此发展高效节水灌溉农业是我国农业持续性发展的首要条件。目前绝对多数节水灌溉控制系统不仅功能单一,而且在控制方式上主要以有线控制为主。这样不仅受到控制区域地形的限制,而且架设线路的成本很高。因此科学控制方法且具备无线遥控的节水灌溉控制系统的研制,成为节水灌溉科学实施的核心问题。本文在充分调研了国内外节水灌溉状况的基础上,研究和分析无线节水灌溉控制系统的控制原理,并重点论述了无线节水灌溉控制系统的硬件设计和软件设计。在硬件设计方面,本文根据仪器的精度、实时性和成本要求,选择了合适的元器件,并以模块化的设计思路将仪器硬件分成几个模块进行分别的设计,各个模块调试成功后再合成一个完整的系统:从而保证了硬件的质量和便于维修调试。在软件设计方面,按照仪器预定完成的功能,根据硬件电路的设计,以模块化的设计方法完成单片机的初始化,模拟信号采样,信号处理,实时显示驱动、无线发射接收,以及PC机端的界面设计,串口通信设计等。另外本系统通过太阳能电池供电,这样阴雨天气系统就不需工作,大大节省了能源和劳力,从而提高了系统的效率。无线节水灌溉控制系统的工作方式采用命令应答方式,主站下达采集数据指令,子站对主站发出的地址信息进行处理,若与本机地址相符则执行命令。采集端将TDR-3土壤水分传感器、CHT-WO2温湿度传感器等采集的作物生长的环境参数(土壤水分、空气湿度和温度等)经A/D转换模块转换成数字信号送到子站单片机,子站单片机对采集过来的信号进行编码、并对编码信号加起始位和校验码,构成传输的数据桢,桢信号通过无线射频收发芯片PTR8000按照一定的协议进行打包,加入字头和CRC(循环冗余校验),将作物生长的环境参数(土壤水分、空气湿度和温度等)发送到主站,主站的接收天线接收载波信号经滤波电路消噪后,通过无线射频收发芯片PTR8000解调,再由主站单片机解码,解码后的信号经PC机存入数据库,同时根据软件设计的灌溉预报模块和灌溉控制模块决策出作物需水量情况,并经过驱动电路控制电磁阀的开闭和电磁阀打开的时间。更多还原

【Abstract】 The freshwater resource is lacking in China,hence, developing the high efficient saving-water irrigated argriculture is the initial requirement to the sustainable agricultural development. At present,most water-saving irrigation control system have singal function,and which mainly employ wired control mode. So the control system is limited by the landforms,furthermore constructing wires costs too much. Thus researching a wireless system with scinentific controlling means has becoming the central issue to scientific applicate of water-saving irrigation.The paper studies and analysis the control principles of the wireless water-saving irrigation control system,and foucus on the design of hardware and software based on sufficient researches on national and foreign status of water-saving irrigation.In the respect of hardware design, according to the precision, time and the cost of the detector, we select the appropriate chips and divide the whole hardware system into several modules to design respectively following the theory of module design. When each module is adjusted successfully, we combine them into a complete entity to ensure the high quality of hardware and makes it easy to test and maintain. In the respect of software, according to the predicted function of this detector and the design of the hardware circuit, the software is specified as follows: initialization for MCU and system chips, sampling analog signals, signal process, real time display and serial port communication on MCU, and program interface design, serial port communication etc. The system needn’t work in the wet weather,so efficiency is raised and energy is saved as well as labour because solar cells are used to offer power.The control system works in the way of command response,the master station gives the order to collect data, the sub-station processes the address information from the master and carries the order out if the address fits the local address . Environmental parameters of growing planta (soil moisture,air humidity and temperature) are send to PC in substation after changing them to digital signals by A/D transformation module. The PC encodes the signals and adds start bit as well as check sodes into the coded signals to form transmittal data frames. PTR8000 packes Frame signals under specified agreement,addes head word and CRC into signals,then sents them to master station.After eliminating noises ,carrier singals received by receiving aerial are demodulated by PTR8000 .Then the PC decodes them and put them into database. At the same time ,the the irrigation forecast and control module are designed to determine water requirement of plants to control opening or closing the electromagnetically operated valve by the drive circuit.更多还原