Key Points Product: Quartz Flexure Accelerometer Key Features: Components: Employs quartz flexure technology for high sensitivity and low noise in measuring acceleration. Function: Suitable for both static and dynamic acceleration measurements, with minimal impact from low-pressure environments. Applications: Ideal for monitoring micro-vibration in spacecraft orbits and applicable in inertial navigation systems. Performance Analysis: Demonstrates negligible scale factor changes (less than 0.1%) in vacuum conditions, ensuring accuracy and reliability. Conclusion: Offers robust performance for long-term on-orbit applications, making it suitable for high-precision aerospace requirements. The quartz flexure accelerometer has the characteristics of high sensitivity and low noise, making it suitable for measuring both static and dynamic acceleration. It can be used as an acceleration-sensitive sensor for monitoring micro-vibration environments in spacecraft orbits. This article mainly introduces effect of low pressure environment on quartz flexible accelerometer. The sensitive diaphragm of the quartz accelerometer experiences membrane damping effects when in motion in the air environment, which could potentially cause changes in the sensor’s performance (scale factor and noise) in low-pressure environments. This could affect the accuracy and precision of measuring on-orbit micro-vibration acceleration. Therefore, it is necessary to analyze this effect and provide a feasibility analysis conclusion for the long-term use of quartz flexible accelerometers in high vacuum environments. Fig.1 Quartz Accelerometers In Spacecraft Orbits 1.Damping analysis in low-pressure environments The longer the quartz flexure accelerometer operates in orbit, the more air leakage occurs inside the package, resulting in lower air pressure until it reaches equilibrium with the space vacuum environment. The average free path of air molecules will continuously lengthen, approaching or even exceeding 30μm, and the airflow state will gradually transition from viscous flow to viscous-molecular flow. When the pressure drops below 102Pa, it enters the molecular flow state. The air damping becomes smaller and smaller, and in the molecular flow state, the air damping is almost zero, leaving only electromagnetic damping for the quartz flexible accelerometer diaphragm. For quartz flexure accelerometers that need to operate for a long time in low-pressure or vacuum environments in space, if there is significant gas leakage within the required mission life, the membrane damping coefficient will significantly decrease. This will change the characteristics of the accelerometer, making scattered free vibrations ineffective in attenuation. Consequently, the scale factor and noise level of the sensor may change, potentially affecting measurement accuracy and precision. Therefore, it is necessary to conduct feasibility tests on the performance of quartz flexible accelerometers in low-pressure environments, and compare the test results to assess the extent of the impact of low-pressure environments on the measurement accuracy of quartz flexible accelerometers. 2.Impact of low-pressure environments on the scale factor of quartz flexure accelerometers Based on the analysis of the working principles and application environments of quartz flexible accelerometer products, it is known that the product is encapsulated with 1 atmosphere pressure, and the application environment is a low Earth orbit vacuum environment (vacuum degree approximately 10-5 to 10-6Pa) at a distance of 500km from the ground. Quartz flexible accelerometers typically use epoxy resin sealing technology, with a leakage rate generally guaranteed to be 1.0×10-4Pa·L/s. In a vacuum environment, the internal air will slowly leak out, with the pressure dropping to 0.1 atmosphere pressure (viscous-molecular flow) after 30 days, and dropping to 10-5Pa (molecular flow) after 330 days. The impact of air damping on quartz flexure accelerometers mainly manifests in two aspects: the impact on the scale factor and the impact on noise. According to design analysis, the impact of air damping on the scale factor is approximately 0.0004 (when the pressure drops to vacuum, there is no air damping). The calculation and analysis process is as follows: The quartz flexure accelerometer uses the gravity tilt method for static calibration. In the accelerometer’s pendulum assembly, in an environment with air, the normal force on the pendulum assembly is: mg0, and the buoyant force fb is: ρVg0. The electromagnetic force on the pendulum is equal to the difference between the force it experiences due to gravity and the buoyant force, expressed as: f=mg0-ρVg0 Where: m is the mass of the pendulum, m=8.12×10−4 kg. ρ is the density of dry air, ρ=1.293 kg/m³. V is the volume of the moving part of the pendulum assembly, V=280 mm³. g0 is the gravitational acceleration, g0=9.80665 m/s². The percentage of the buoyant force to the gravitational force on the pendulum assembly itself is: ρVg0/mg0=ρV/m≈0.044% In a vacuum environment, when the air density is approximately zero due to gas leakage causing the pressure inside and outside the instrument to balance, the change in scale factor of the quartz flexible accelerometer is 0.044%. 3.Conclusion: Low-pressure environments can affect the scale factor and noise of the quartz flexible accelerometer. Through calculation and analysis, it’s shown that the maximum impact of the vacuum environment on the scale factor is not more than 0.044%. Theoretical analysis indicates that the influence of low-pressure environments on the sensor’s scale factor is less than 0.1%, with minimal impact on measurement accuracy, which can be neglected. This demonstrates that low-pressure or vacuum environments have minimal effects on the scale factor and noise of the quartz flexure accelerometer, making it suitable for long-term on-orbit applications. It’s worth noting that the AC7 series quartz flexible accelerometers are designed specifically for aerospace applications. Among them, the AC7 has the highest precision, with zero bias repeatability ≤20μg, a scale factor of 1.2mA/g, and scale factor repeatability ≤20μg. It is fully suitable for monitoring micro-vibration environments of spacecraft in orbit. Additionally, it can be applied to inertial navigation systems and static angle measurement systems with high precision requirements.   AC-5 Low Deviation Error Accelerometer Quartz Vibration Sensor for Imu Ins    

Key Points Product: Quartz Flexible Accelerometer Key Features: Components: Uses high-precision quartz flexible accelerometers for accurate acceleration and tilt measurements. Function: Vibration analysis helps identify sensor error coefficients, improving measurement accuracy and performance. Applications: Widely used in structural health monitoring, aerospace navigation, automotive testing, and industrial machinery diagnostics. Data Analysis: Combines vibration data with signal processing algorithms to optimize sensor models and enhance performance. Conclusion: Delivers precise and reliable acceleration measurements, with strong potential in various high-precision industries. 1.Introduction: In the realm of sensor technology, accelerometers play a pivotal role in various industries, from automotive to aerospace, healthcare to consumer electronics. Their ability to measure acceleration and tilt across multiple axes makes them indispensable for applications ranging from vibration monitoring to inertial navigation. Among the diverse types of accelerometers, quartz flexible accelerometers stand out for their precision and versatility. In this article, we delve into the intricacies of identifying quartz flexible accelerometers through vibration analysis, exploring their design, working principles, and the significance of vibration analysis in optimizing their performance. 2.Importance of Vibration Analysis: For the accelerometer to be identified, first, conduct multi-directional vibration table tests on it. Obtain rich raw data through data acquisition software. Then, based on the test data, on the one hand, combine the overall least squares algorithm to identify its high-order error coefficients, improve its signal model equation, enhance the measurement accuracy of the sensor, and explore the relationship between the high-order error coefficients of the accelerometer and its operating status. Seek methods to identify its operating status through the high-order error coefficients of the accelerometer. On the other hand, extract its effective feature set, train neural networks, and finally modularize the effective data analysis algorithm through virtual instrument technology. Develop application software for identifying the operating status of quartz flexible accelerometers to achieve rapid and accurate identification of sensor operating status. This will help personnel to promptly improve internal circuit structures, enhance the measurement accuracy of accelerometers, and improve the yield of manufactured products during the processing and manufacturing process. Vibration analysis serves as a cornerstone in the characterization and optimization of quartz flexible accelerometers. By subjecting these sensors to controlled vibrations across different frequencies and amplitudes, engineers can evaluate their dynamic response characteristics, including sensitivity, linearity, and frequency range. Vibration analysis helps identify potential sources of error or non-linearity in accelerometer output, enabling manufacturers to fine-tune sensor parameters for enhanced performance and accuracy. 3.Identification Process: The identification of quartz flexible accelerometers through vibration analysis involves a systematic approach encompassing experimental testing, data analysis, and validation. Engineers typically conduct vibration tests using calibrated shakers or vibration excitation systems, exposing the accelerometers to sinusoidal or random vibrations while recording their output signals. Advanced signal processing techniques such as Fourier analysis and spectral density estimation are employed to analyze the frequency response of the accelerometers and identify resonance frequencies, damping ratios, and other critical parameters. Through iterative testing and analysis, engineers refine the accelerometer model and validate its performance against specified criteria. 4.Applications and Future Prospects: Quartz flexible accelerometers find applications across a diverse array of industries, including structural health monitoring, aerospace navigation, automotive testing, and industrial machinery diagnostics. Their high precision, robustness, and versatility make them indispensable tools for engineers and researchers striving to understand and mitigate the effects of dynamic forces and vibrations. Looking ahead, ongoing advancements in sensor technology and signal processing algorithms are poised to further enhance the performance and capabilities of quartz flexible accelerometers, unlocking new frontiers in vibration analysis and dynamic motion sensing. In conclusion, the identification of quartz flexible accelerometers through vibration analysis represents a critical endeavor in sensor technology, enabling engineers to unlock the full potential of these precision instruments. By understanding the working principles, conducting thorough vibration analysis, and refining sensor performance, manufacturers and researchers can harness the capabilities of quartz accelerometers for a myriad of applications, ranging from structural monitoring to advanced navigation systems. As technological innovation continues to accelerate, the role of vibration analysis in optimizing sensor performance will remain paramount, driving advancements in precision measurement and dynamic motion sensing. 5.Conclusion Micro-Magic Inc provides high-precision quartz flexible accelerometers, such as AC1, with small error and high precision, which have a bias stability of 5μg, scale factor repeatability of 15~50 ppm, and a weight of 80g, and can be widely used in the fields of oil drilling, carrier microgravity measurement system, and inertial navigation.   AC1 Navigation Class Level Quartz Flexible Accelerometer With Measurement Range 50G Excellent Long-Term Stability And Repeatability