Micromechanical Gyroscope Coupling Structure for Z-Axis Detection
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Solution Overview
Problem
Existing micromechanical sensor devices for measuring angular z-axis motion are complex and prone to perturbation modes, making them difficult to control and resulting in unwanted vibrations that affect the accuracy of z-axis rotation detection.
Innovation Solution
A micromechanical sensor device with a compact structure featuring two vibratory structures suspended above a substrate, connected by a coupling structure that allows anti-phase vibrations, eliminating the need for sense-mode shuttle masses and leveraging distinct spring constants for drive-mode and sense-mode directions to separate frequencies and reduce unwanted modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional micromechanical sensor devices use multiple shuttle masses and complex coupling mechanisms, then the device can detect z-axis rotation, but the device complexity increases and perturbation modes are introduced
Solution Approach 1:
The patent removes sense-mode shuttle masses from the traditional gyroscope structure, extracting only the essential proof masses that are needed for rotation detection. This simplification eliminates the complex coupling mechanisms between multiple shuttle masses while maintaining the core functionality of detecting z-axis rotation through Coriolis acceleration.
Solution Approach 2:
The patent divides the vibratory structure into distinct functional components: proof masses for sensing and simple suspension elements for support. By segmenting the structure into these independent functional units connected by simple suspension, the design achieves clarity in function while reducing overall complexity compared to integrated shuttle mass designs.
2Measurement precision
If traditional designs use rigid levers to couple proof masses, then anti-phase motion is achieved, but spurious frequency modes are introduced that affect measurement accuracy
Solution Approach 1:
The patent replaces rigid mechanical levers with flexible suspension structures that provide the necessary coupling between proof masses. This substitution eliminates the spurious frequency modes associated with rigid lever mechanisms while maintaining the anti-phase motion required for accurate rotation detection through the flexible, compliant nature of the suspension.
Solution Approach 2:
The patent changes the mechanical parameters of the coupling mechanism from rigid (high stiffness) to flexible (compliant suspension). This parameter change transforms the system from one that generates spurious frequency modes with rigid levers to one that naturally filters such modes while maintaining the desired anti-phase vibrational behavior for Coriolis sensing.
3Measurement precision
If sense-mode shuttle masses are used to detect Coriolis acceleration, then rotation sensing is enabled, but the number of vibrating modes increases making control difficult
Solution Approach 1:
The patent extracts and removes the sense-mode shuttle masses from the system, relying instead on the proof masses themselves to detect Coriolis acceleration. This extraction reduces the total number of vibrating components from multiple shuttle masses to fewer proof masses, significantly simplifying vibration mode control while preserving the essential Coriolis sensing function.
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 simplifies the design, reduces the number of vibrating modes, and enhances the separation of in-phase and anti-phase frequencies, leading to improved control over drive-mode and sense-mode vibrations, thereby increasing the accuracy and reliability of z-axis rotation detection.
Implementation Method 1
each of the vibratory structures comprises at least one shuttle mass coupled to the at least one proof mass by sense-mode springs, which are more flexible in sense-mode direction than in drive-mode direction
Implementation Method 2
at least one drive electrode structure for each shuttle mass for activating drive-mode movements that are parallel to the substrate plane
Implementation Method 3
at least one sensing electrode structure for each proof mass for detecting sense-mode movements that are parallel to the substrate plane
Implementation Method 4
at least one coupling support structure connecting the coupling structure to at least one anchor structure and enabling a rotational swinging movement of the coupling structure, the rotational swinging movement having an axis of rotation that is perpendicular to the substrate plane
Implementation Method 5
The driven oscillation combined with rotation of the substrate about an axis perpendicular to the substrate results in Coriolis acceleration along the other mode of compliance, the sense-mode
Data Source
AI summary
A micromechanical sensor device for measuring angular z-axis motion comprises two vibratory structures (2.1, 2.2, 7.1, 7.2) each having at least one proof mass (2.1, 2.2). A suspension structure (3.1, 4.1, 4.2, 5.1, 6.1, ..., 6.4) maintains the two vibratory structures (2.1, 2.2, 7.1, 7.2) in a mobile suspended position above the substrate (1) for movement parallel to the substrate plane in drive-mode direction (x-axis) and in sense-mode direction (y-axis). A coupling support structure (4.1, 4.2) connects the coupling structure (5.1, 5.2, 6.1, ... 6.4) to an anchor structure (3.1, 3.2) and enables a rotational swinging movement of the coupling structure (5.1, 5.2), the rotational swinging movement having an axis of rotation that is perpendicular to the substrate plane. Each of the vibratory structures (2.1, 2.2, 7.1, 7.2) comprises at least one shuttle mass (7.1, 7.2) coupled to the at least one proof mass (2.1, 2.2) by sense-mode springs (8.1, ..., 8.4), which are more flexible in sense-mode direction than in drive-mode direction (x), for activating a vibration movement of each vibratory structure (2.1, 2.2, 7.1, 7.2). A sensing electrode structure (10.1, 10.2) for each proof mass (2.1, 2.2) is designed for detecting sense-mode movements that are parallel to the substrate plane, The coupling support structure (4.1, 4.2) is designed to also enable a translational movement of the coupling structure (5.1, 5.2, 6.1, ... 6.4) in drive-mode direction (x).