【作者】 许述财；

【导师】 李建桥； 李因武；

【作者基本信息】 吉林大学 ， 农业机械化工程， 2004， 硕士

【摘要】 面向农机部件性能测试的四套虚拟仪器研究在农业工程试验研究中，无论是分析农机具的减粘降阻机理，探索减粘降阻规律，还是研究地面机械行走装置和工作部件的减粘脱附技术，都需要对研究过程中所做的各种试验进行数据采集与分析。另一方面，随着电子技术的广泛发展和应用，农业工程试验对试验数据测试精度的要求越来越高，这使得试验中对测试仪器的性能要求也越来越高，为既能取得满意的试验结果又可以降低试验经费，对虚拟测试仪器的研究与探索，将成为改善农业工程试验的一种新的方法。虚拟仪器自1986年美国NI公司提出至今，已显得不再陌生。它的出现，是向传统仪器的挑战，是测试与测量领域的一次技术创新，同时也是该领域发展的一种崭新趋势。尽管目前国内外对其都积极的研究，但限于该项技术发展还不是很成熟，目前国内对于该项技术还存在着中文资料匮乏、使用稳定性不高、推广面较窄等一系列问题，这些都阻碍了虚拟测试仪器体系的研究和应用技术的开发。本文在考察国内外前期虚拟测试仪器研究的基础上，根据实验室现有的硬件设备和农业工程试验的需要，作者利用组态化软件DASYLab和软件DAQView设计开发出了相比传统测试仪器具有占地空间小和价格低等四套虚拟测试仪器，即：16通道应力应变高速虚拟测试仪器、多通道电压信号虚拟测试仪器、应力与温度多功能虚拟测试仪器、单通道应力应变虚拟测试仪器，并将所开发出的虚拟测试仪器用于了模型铲刀推土试验、仿生犁壁减粘降阻试验、仿生开沟器减粘降阻分析等试验。旨在验证开发出的虚拟测试仪器的可行性和相比与传统仪器的优点，并主要为农业工程试验的研究提供更加完善的研究手段。本文研究的各种虚拟测试仪器由笔记本电脑、数据采集系统和组态化软件DASYLab或软件DAQView等组成。本文在开发虚拟测试仪器软件系统的过程中，充分利用了组态化软件DASYLab的A/D模数功能转换模块；信号处理模块：FFT和Filter模块；显示功能模块Dig.meter、Analog、Y/t、Recorder、Message等及辅助功能模块Action、Time Base、Switch、Select等的多种功能，并合理选用和链接这些功能模块。设计开发出的虚拟测试仪器不仅满足了相<WP=106>应的试验要求，同时还具有各种友好的虚拟工作界面，试验者能够随调随用。在功能扩展方面，虚拟测试仪器随着试验条件的不同只需更改所选功能模块的相应性能参数即可；随着输入信号的不同，虚拟测试仪器只需更换虚拟仪器硬件部分的信号调理模块并需更改所选功能模块的性能参数。本文开发的四套虚拟测试仪器通过功能测试和验证试验，结果表明：虚拟测试仪器除了具有相应传统测试仪器的一般功能外，在操作方便性、实时显示可选形式、实时存储格式及试验数据回放和试验数据分析处理等方面均优于传统测试仪器。另外，虚拟测试仪器与计算机相连且其功能以软件为核心，与以固化硬件功能的传统测试仪器相比，具有功能开发和扩展费用低、技术更新周期短、较好的开放性、灵活性及一机多能等优点，尤其具有较高的性价比。最后，虚拟测试仪器还具有占用空间小，无需网络电源供电，非常适合野外操作的优点。利用所设计开发的四套虚拟测试仪器，进行了仿生犁壁犁地阻力、仿生模型铲刀表面所受推土阻力和仿生开沟器的减粘降阻规律等三个主要试验，数据分析结果表明：每套虚拟仪器所采数据反映的试验过程与实际试验过程吻合很好，基本无奇异点，无数据丢失，采样频率及仪器各项性能参数设置合理可用。对于恶劣环境下的各种农业工程试验，我们还需进一步开发出具有远程控制和反馈控制等功能的虚拟测试仪器，这是本文对虚拟测试仪器的发展展望。本文的研究工作为进一步进行农业工程试验研究、对各种农机具性能的完善和优化设计提供了很好的研究手段。更多还原

【Abstract】 Study on Four Sets of Virtual Instruments for Testing Properties of Agricultural-Machine ComponentsDuring the research of agricultural engineering’s experiment, it is necessary to collect and analyze data being relative to all sorts of experiment either for the purpose of analyzing the mechanism of reducing adhesion and resistance of the agricultural machine and exploring its discipline, or for the purpose of researching reducing resistance and desorption of the walking and working device of ground machines. On the other hand, as the developing and applying of electronic technologies, the agricultural engineering’s experiment is more and more strict with measurement precision of experiment’s data. As a result, the more and more requirements of measurement instrument quality are needed. In order to get satisfying experiment results and low the cost of experiment, the research and the exploring of the virtual instrument will be developed into a new method of improving the agricultural engineering’s experiment.The virtual instrument has already not as strange as it was used to be, since it was presented by the IN company in 1986. The appearance of the virtual instrument was a challenge to the traditional instrument and a technologic creation in the field of measurement, as well as a new trend of this field. Although many active researches have been done about the virtual instrument in our and some other country, in China there are still many questions, such as the lack of Chinese material, the instability, the application still limited, and so on. All of these have already been obstacles to researching it deeply and deploring the method to be used widely.In this article, the author reviewed the domestic and overseas early research on virtual instruments. In order to satisfy needs of the agricultural engineering experiment considering hardwires of his laboratory and taking advantage of the configuration software DASYLab and the software DAQView, the author finally designed four virtual instruments with the lower <WP=108>price and occupying smaller room: the 16 channels stress-strain fast virtual test instrument, the many channels voltage signal virtual test instrument, the multi-function of stress and temperature virtual test instrument, the single channel stress-strain virtual test instrument, furthermore, the author made use of these virtual instruments into many experiments, such as, bulldozing experiments of model blade, the experiment to reduce adhesion and resistance of the bionic plow, the experiment to reduce adhesion and resistance of the bionic ditcher, etc, to verify these virtual instruments’ feasibility and the advantages compared with the traditional ones, trying to provide the better research method of the agricultural engineering experiment.The virtual instruments, which are researched in this paper, made up of the notebook PC, the system of data collection, and the configuration software DASYLab or the software DAQView, etc. During the process of exploitation of the software system of the virtual instruments in the paper, the author took full advantage of the transform module of the A/D of the DASYLab; the module of Dig. meter, Analog, Y/t, Recorder, Message, etc; the module of Action, Time Base, Switch, Select, FFT、Filter,etc and choosing and linking those modules reasonably. The virtual instruments designed in the paper can fulfill the demand of the experiment, as well as have the friendly interface. The experimenters can use them at will.In the side of the expanding of function, to accord with the different conditions of experiments these Virtual Instruments only need be changed the parameters of the relevant function modules; to accord with the different input these Virtual Instruments only need to be changed those transform signals modules of their hardwires and corresponding parameters of these modules.Through the testing of function and the experiments, a conclusion about the four Virtual Instruments developed in this paper can be presented: compared with the traditional test更多还原