Resonator Stress Isolation via Segmented Mass-Spring Network
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gyroscope resonator designs face challenges in optimizing multiple properties simultaneously due to a fixed relationship between mass and stiffness, leading to suboptimal performance in stress isolation and frequency operation, with stresses affecting bias and damping unpredictably.
Innovation Solution
The resonator is separated into thin compliant 'spring' elements and stiff 'mass' elements, with a stress isolation network of concentric symmetric regions of varying stiffness, allowing independent control of spring constant, mass, thermoelastic loss, and operating frequency, and incorporating slots to reduce stress asymmetry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fully distributed mass/spring geometry is used, then the resonator structure is simple and manufacturable, but the relationship between mass and stiffness is fixed, limiting optimization freedom
Solution Approach 1:
The resonator is segmented into discrete mass elements and discrete spring elements rather than using a fully distributed continuous structure. This segmentation allows independent optimization of mass distribution and stiffness distribution, providing multiple degrees of freedom for optimizing the resonator geometry while maintaining manufacturability through standard fabrication processes.
2Strength
If stresses propagate into the resonator, then the resonator is structurally connected to the mounting, but the stresses cause mode splitting and bias errors in gyroscope performance
Solution Approach 1:
A stress isolation network is introduced as an intermediary structure between the mounting and the resonator active area. This network comprises concentric symmetric regions of alternating high and low stiffness that decouple external mounting stresses from the resonator, preventing stress-induced mode splitting and bias errors while maintaining structural support.
Solution Approach 2:
The resonator structure employs local variations in stiffness through the stress isolation network, with concentric regions of high stiffness providing structural support and low stiffness regions isolating stresses. This local differentiation allows the structure to simultaneously maintain strength and protect the resonator from stress-induced performance degradation.
3Adaptability or versatility
If discrete masses on discrete springs are used, then optimization freedom increases, but the device complexity increases compared to distributed designs
Solution Approach 1:
The resonator is segmented into discrete mass elements and discrete spring elements arranged in a systematic pattern around the periphery. This segmentation provides multiple degrees of freedom for independent optimization of mass and stiffness distributions while maintaining a relatively simple overall structure that can be fabricated using standard processes, thus achieving optimization freedom without excessive complexity.
Data Source
AI summary
To isolate an active portion of a gyroscope resonator from mounting stresses propagating through a resonator attachment center, the resonator includes a stress isolation feature that includes alternating concentric symmetric regions of high and low stiffness. The resonator may be separated into a large number of thin, compliant spring elements and larger stiff mass elements, the aggregate areas of which optimized for an aggregate resonator spring constant (by selecting a width and a length of the spring elements), an aggregate mass (by selecting a size of the mass elements), a thermoelastic loss maximum (by selecting a width of the spring elements) and an operating frequency (by selecting a ratio of the aggregate spring to the aggregate mass).