飞机电缆屏蔽层接地可靠性测试系统设计

Design of Aircraft Cable Shield Grounding Reliability Test System[JZ)][HS)]

摘要:

飞机电缆屏蔽层可靠接地对飞机建立完整屏蔽环路,防止复杂电磁场对飞机内部电路产生干扰具有重要意义;因此,接地可靠性测试尤为必要;测试系统以NI CompactRIO机箱为核心,通过连接上位机、辅助电路以及测试工具搭建硬件测试平台,利用LabVIEW可视化编程语言编写控制程序;上位机程序,通过状态机实现人工交互以及系统整体逻辑控制;FPGA控制程序,用于驱动硬件完成信号的产生和采集工作;实时处理器程序,采用DMA技术与FPGA进行通讯,对辅助电路反馈的采集数据进行快速傅里叶变换提取有效信号,随后应用矢量电压电流法求解电缆屏蔽层环路阻抗;实际测量结果证明:基于LabVIEW的飞机电缆屏蔽层接地可靠性测试系统能够以较高精度完成电缆屏蔽层接地可靠性测试。

Abstract:

Aircraft cable shielding is necessarily well-grounded to establish a complete shielding loop to prevent the interfering on the internal circuitry from the complex electromagnetic environment. Therefore, grounding reliability test is particularly necessary. In this test system, NI CompactRIO chassis is used as the main core to build hardware test platform, co-operating with host computer, auxiliary circuit and test tools, and LabVIEW visual programming language is used as the software tool for system design. The program on the host computer, utilizes a state machine to implement the user interface and the overall control logic of the system. The FPGA is programmed to drive the hardware to complete signal generation and acquisition simultaneously. The real-time processor program communicates with FPGA using Direct Memory Access technique, the feedback data from the auxiliary circuit is collected and processed by the method of Fast Fourier Transform, and further the vector voltage and current method is applied to calculate the loop impedance of the cable shielding. Measurement results show that:the aircraft cable shield grounding reliability test system based on LabVIEW is able to complete grounding reliability tests with high accuracy.