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Ultra-low frequency vertical vibration isolator based on LaCoste spring linkage
1Joint Institute for Measurement Science, Tsinghua University, Beijing 100084, China.
The Review of Scientific Instruments
|November 3, 2014
Summary
This study presents an ultra-low frequency vibration isolator for precision measurements. The novel design significantly improves absolute gravimeter performance, achieving 2 μGal uncertainty.
Area of Science:
- Geophysics
- Mechanical Engineering
- Instrumentation
Background:
- Precision measurements, such as absolute gravimetry, are sensitive to environmental vibrations.
- Existing vibration isolation systems may not meet the stringent requirements for ultra-high precision measurements.
Purpose of the Study:
- To design and build an ultra-low frequency vertical vibration isolator for applications in precision measurement.
- To evaluate the vibration isolation performance of the developed system for absolute gravimetry.
Main Methods:
- A LaCoste spring linkage mechanism was employed, suspending a test mass with a feedback-controlled system.
- Optical reflection detected arm displacement, enabling a feedback control force to maintain balance.
- Dynamic characteristics of the spring linkage were analyzed to adjust the natural oscillating period.
Main Results:
- The vibration isolator achieved a natural oscillating period of up to 32 seconds.
- Testing with the T-1 absolute gravimeter resulted in a statistical uncertainty of 2 μGal within 12 hours.
- The system demonstrated significant vibration isolation capabilities.
Conclusions:
- The developed ultra-low frequency vibration isolator is highly effective for high-precision absolute gravity measurements.
- The feedback control mechanism successfully corrects for systematic drift, including temperature variations.
- The isolator's performance validates its suitability for demanding geophysical applications.
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