基于数字零中频纳米位移遥测技术研究

Research on nanometer displacement telemetry based on digital zero intermediate frequency

针对航空航天领域对超静平台纳米量级位移遥测的需求,研制了一套体积小、质量轻、便携式的激光多普勒纳米位移遥测系统;系统在电学部分采用基于数字零中频的解调方案,模拟器件的减少有助于提高系统的探测准确度和精度;理论分析了基于数字零中频的纳米位移振动解调算法,并进行了算法实现和试验验证,研究结果表明,该算法最小探测相位达到1°,对应振动位移2.15 nm。在此基础上,利用PI-E501标准振动源,在作用距离为10 m处,对研制的激光多普勒纳米位移遥测系统进行了性能测试,实现了振动频率10 Hz和1 000 Hz下和幅度1 000、200、10 nm的遥测,测试结果表明:该遥测系统满足工作频段在几十到几百赫兹,振动位移为微米甚至更低的航空航天领域对超静平台测量的要求。

A small volume,light weight,portable laser Doppler nanometer displacement telemetry system was presented that meet the demand of nanometer detection for the ultra-stable platform in the aerospace industry.In the electrical module,the system adopted the demodulation scheme based on digital zero intermediate frequency,thus the decrease of the analog devices was helpful to improve the detection resolution and precision of the system.Digital zero intermediate frequency demodulation method for the nanoscale vibration amplitude was analyzed theoretically and implemented.The proof experiment shows that the minimum phase of 1°,equal to vibration amplitude 2.15 nm detectable capacity is achieved.PI-E501 standard vibration source,placed at 10 meter distance from the system,was employed to testify the performance of the laser Doppler nanometer displacement telemetry system and telemetry with amplitudes of 1000,200,10 nm at the frequency 10 Hz and 1000 Hz was achieved.This system performance verification experiment shows that the laser Doppler nanometer displacement telemetry system achieve the ability of dozens of herts to hundred herts frequency,microns or even smaller vibration amplitude detection for the ultra-stable platform in the aerospace industry.