基于虚拟仪器技术的MPT测量系统

【作者】 屈崑；

【导师】 毛根旺；

【作者基本信息】 西北工业大学 ， 航空宇航推进理论与工程， 2002， 硕士

【摘要】 电推进技术具有很大的潜力，已经引起学术和航天工业界的兴趣和重视，并且越来越多地被应用到空间任务中。电推进研究室为了对微波等离子推力器(MPT)进行进一步的实验研究，对原有的实验系统作改造以满足需求。 由于目前实验研究在实验对象、测量参数、测量状态等方面具有很大的不确定性，因此需要保证实验系统功能的灵活性和可扩展性的要求。而以功能灵活、扩展能力强、组建方便、成本低廉为特点的虚拟仪器技术正好可以满足这方面的需要，因此新的实验系统采用虚拟仪器技术构造。 本文完成的工作有： 1．以一台个人计算机为核心，AT-MIO-16E-10多功能数据采集卡为数据采集设备，配合外部传感器和仪器进行数据采集和控制，构建了测量系统硬件。 2．同时本文在分析了传统测试软件的缺陷，指出其缺乏数据管理或者实验工程管理，无法满足规模较大、较复杂的实验研究需要以后提出了在测试软件中集成实验工程管理的概念和实现的方法，并以此为基础将数据采集技术、数据库技术和OLE技术结合，采用Labwindows／CVI、Powbuilder、Acess20000和Excell2000为软件平台，设计实现了集测试、实验工程管理和数据管理一体化的虚拟仪器软件，在测试软件结构方面作了有意义的探讨和尝试。 3．使用开发成功的MPT虚拟仪器测试系统进行了MPT的真空和大气条件下启动点火热试，以He气和Ar气为工质测得了大气环境和真空环8种状态下MPT稳态运行的数据。这些数据表明He气的反射功率有明显的极小值，而对于Ar气，反射功率则随着流量增加而单调减小；随着入射功率增大，He的最小反射点对应的流量增大。实验还发现功率条件接近时，He气在真空环境和大气环境下的反射功率有所不同，这可能是由于谐振腔外部尾流形状及其电子浓度分布受到环境压力影响而改变，从而间接影响了谐振腔的电磁特性之故。 实验证实MPT虚拟仪器测试系统设计是可行的，为进一步工作打下了基础。更多还原

【Abstract】 Over the past two years there has been an MPT (microwave plasma thruster) expreiment system in EPRC (Electric Propulsion Reaserch Section). In order to make further experimental study on MPT, EPRC update the old MPT measurement system. Taking account of the uncertainty of the experiments, the flexibility and expansibility are required. The virtual instrument technology is applied to construct the new MPT measurement system.The contents of this paper include:1. A new measurement system was developed, which was based on a PC and equiped with an AT-MIO-16E-10 multifunction I/O borad and other peripheral instruments.2. The limitation of the traditional measuring software was analyzed, and the intergrating idea and method of measuring function and the function of experiment projects management, as well as experiment data management were proposed, on the base of which the new MPT experiment system was developed with Labwindows/CVI, Powerbuilder, Excell 2000 and Access 2000.3. Then with the new system, eight group working data of MPT in atmosphere and vacuum environment were acquired. The data show that there is a minimum of reflected microwave power for helium when the flowrate increases, but for argon the reflective microwave power decreases while the gas flow increases in the special flowrate range. At the same time, at the approximate microwave power the reflected power under atmosphere enviroment and that under vacuum enviroment are diferent, ’which maybe result from the enviroment pressure disturbing the plume shape and electron density in it to change the electromagnetic characteristics of the resonance chamber.The experiments proved that the MPT measurement system is feasible and prepared for the future research.更多还原