Vibrating Beam Accelerometer Isolation Structure for Axial Strain
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Solution Overview
Problem
Vibrating beam accelerometers face measurement errors due to unintended axial strain on mounting pads caused by the movement of elongated beams, which affects the accuracy and precision of acceleration and orientation sensing.
Innovation Solution
The implementation of segmented isolation blocks between mounting pads and resonating tines reduces axial strain and end-pumping, improving measurement accuracy by balancing lateral movement and counteracting the strains induced by resonator vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resonating tines are directly connected to mounting pads, then the structure is simple and easy to manufacture, but axial strain and end-pumping occur during resonance causing measurement errors
Solution Approach 1:
The resonator structure is segmented into distinct functional blocks: mounting pads, pad connectors, isolation blocks (with inner and outer segments), and resonating tines. This segmentation allows the isolation blocks to be positioned between the mounting pads and tines, creating a mechanical decoupling that reduces axial strain transmission to the mounting pads during resonance, thereby improving measurement accuracy while maintaining manufacturing feasibility through modular construction
Solution Approach 2:
Isolation blocks serve as intermediary elements positioned between the mounting pads and the resonating tines. These isolation blocks act as mechanical mediators that decouple the resonance vibrations from the mounting pads, reducing the axial strain and end-pumping effects that would otherwise be directly transmitted to the mounting pads and cause measurement errors
2Measurement precision
If isolation blocks are added between mounting pads and tines, then axial strain and measurement error are reduced, but the resonator structure becomes more complex
Solution Approach 1:
The resonator structure is segmented into distinct functional blocks: mounting pads, pad connectors, isolation blocks (with inner and outer segments), and resonating tines. This segmentation allows the isolation blocks to be positioned between the mounting pads and tines, creating a mechanical decoupling that reduces axial strain transmission to the mounting pads during resonance, thereby improving measurement accuracy while maintaining manufacturing feasibility through modular construction
Solution Approach 2:
The isolation mechanism combines multiple elements (outer block, inner block, and interconnect members) into an integrated assembly that functions as a unified isolation system. This merging approach allows the complex isolation function to be achieved through a coordinated structure that can be manufactured and assembled as a cohesive unit, reducing the practical impact of increased complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the accuracy and precision of acceleration and orientation measurements by minimizing measurement errors associated with axial strain, leading to improved performance in navigation, guidance, and positioning systems.
Implementation Method 1
Accelerometers function by detecting the displacement of a proof mass under inertial forces. Another technique is to measure the strain induced in resonators attached a proof mass as they counteract inertial forces of the proof mass.
Implementation Method 2
The strain may, for example, be determined by measuring the change in the frequencies of the resonators as the accelerometer is subjected to an outside force.
Implementation Method 3
Vibrating beam accelerometers (VBAs) in which the resonator has segmented isolation blocks between the mounting pads and resonating tines that may reduce the axial strain or end pumping on the mounting pads from resonance of the tine
Data Source
AI summary
A resonator defining a longitudinal axis that includes a mounting pad, a pad connector, at least one isolation mechanism, and a pair of elongated tines extending in the direction of the longitudinal axis. The isolation mechanism including an outer block defining a first outer end and a second outer end on opposite sides, an inner block defining a first inner end and a second inner end on opposite sides, and a pair of interconnect members, where each respective interconnect member of the pair of interconnect members connects the second outer end to the first inner end. The respective first ends of the pair of elongated tines being connected to the second inner end and the pad connector connects the mounting pad to the first outer end.