MEMS Proof-Mass Coupling for Anti-Phase Gyroscope Oscillation
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Solution Overview
Problem
Single-mass gyroscopes are sensitive to acceleration, which can mask the true angular rotation signal due to acceleration-generated signals being interpreted as angular rotation, and existing coupling structures in MEMS devices struggle to efficiently direct and synchronize oscillation modes without cross-axis interference.
Innovation Solution
A MEMS device with a coupling structure that synchronizes proof masses in anti-phase oscillation using flexible and rigid spring structures, ensuring forces are directed only in the intended direction, minimizing cross-axis motion, and maintaining independent oscillation modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-mass gyroscope is used, then the device structure is simple, but the acceleration-generated signal masks the angular rotation signal
Solution Approach 1:
The single proof mass is segmented into two separate proof masses (first proof mass and second proof mass) that are coupled together. This segmentation allows the system to distinguish between acceleration effects and Coriolis effects by observing the relative motion between the two masses, thereby resolving the signal masking problem while maintaining reasonable structural complexity.
2Measurement precision
If mass pairs oscillate out-of-phase to suppress acceleration signal, then acceleration-generated signal is suppressed, but the coupling structure becomes complex
Solution Approach 1:
A coupling structure acts as an intermediary element between the two proof masses, enabling them to oscillate out-of-phase. This coupling structure is designed to be flexible in the oscillation direction while resisting motion in perpendicular directions, achieving signal suppression without requiring complex multi-component assemblies.
3Force
If coupling structure transfers force in x-direction, then out-of-phase oscillation is achieved, but cross-axis motion occurs in y-direction
Solution Approach 1:
The coupling structure is designed with directionally dependent mechanical properties: it is flexible in the x-direction (allowing out-of-phase oscillation) but stiff in the y-direction (preventing cross-axis motion). This local differentiation of mechanical quality enables the structure to perform its function while blocking harmful cross-axis effects.
4Strength
If primary oscillation amplitude is large, then the oscillation mode is well-defined, but cross-axis interference increases
Solution Approach 1:
The coupling structure implements directional stiffness differentiation, being stiff in the y-direction to prevent cross-axis interference even when primary oscillation amplitude is large. This allows the system to maintain well-defined oscillation modes without suffering from increased cross-axis effects.
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
The solution effectively separates acceleration-induced signals from angular rotation signals, enhancing the accuracy of angular rotation measurements by minimizing cross-axis interference and optimizing oscillation synchronization.
Implementation Method 1
The first coupling structure is configured to transmit force in the primary direction between the first and second proof masses
Implementation Method 2
the other oscillation mode (the secondary oscillation mode) is generated by the Coriolis force when the gyroscope undergoes rotation
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 2c~2e
AI summary
A microelectromechanical device which comprises a first proof mass and a second proof mass. A first coupling structure is configured to transmit force in a primary direction between the first and second proof masses. The first coupling structure is connected to a primary spring structure in a first suspension structure which extends from a first anchor point to the first proof mass. The first primary spring structure is more flexible in the primary direction than in the y-direction.