Micromechanical Rotation Sensor with Mirror Symmetry
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Solution Overview
Problem
Existing micromechanical rotation rate sensors are sensitive to external linear and rotational accelerations, leading to inaccurate measurements and interference, and require significant installation space, limiting their versatility and robustness.
Innovation Solution
A micromechanical component with a mirror symmetrical design of rotor and seismic masses, aligned along two perpendicular planes of symmetry, minimizing movement and coupling under external accelerations, and utilizing rocker structures and phase-shifted harmonic vibrations to suppress interference modes, allowing for robust and accurate 3-axis rotation rate detection with reduced space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional micromechanical sensor designs are used, then the sensor can detect rotational movements, but it is sensitive to external linear and rotational accelerations causing measurement errors
Solution Approach 1:
The patent applies mirror symmetry (a form of controlled asymmetry) by arranging two rotor masses and four seismic masses symmetrically with respect to two perpendicular planes of symmetry. This symmetrical arrangement ensures that external linear and rotational accelerations affect both rotor masses identically, causing equal interference that can be differentially eliminated, thereby improving measurement precision while maintaining rotational sensitivity
Solution Approach 2:
The patent uses counterbalancing through the symmetrical arrangement of masses where the two rotor masses and four seismic masses are positioned to create balanced interference patterns. When external accelerations occur, the symmetrical mass distribution ensures that interference forces on both rotor masses are equal and can be rejected through differential measurement, effectively counteracting the harmful effects of external accelerations
2Adaptability or versatility
If conventional sensor designs are used, then rotational detection is possible, but the sensor requires significant installation space
Solution Approach 1:
The patent combines multiple functional elements into a compact integrated structure. Two rotor masses and four seismic masses are arranged in a shared symmetrical configuration that enables 3-axis rotational detection within a reduced volume, merging what would traditionally require separate sensor components into a single compact micromechanical assembly
Solution Approach 2:
The patent utilizes three-dimensional spatial arrangement by positioning masses symmetrically with respect to two perpendicular planes of symmetry. This 3D configuration allows the sensor to detect rotations about three orthogonal axes simultaneously while minimizing the footprint, effectively using vertical and lateral dimensions to reduce overall installation space
3Measurement precision
If the two rotor masses are set in rotational vibrating motions, then rotation rate can be detected, but coupling between the rotor masses may occur causing interference modes
Solution Approach 1:
The patent employs mirror symmetry to create balanced coupling characteristics between the two rotor masses. The symmetrical arrangement with respect to two perpendicular planes ensures that coupling forces generated during rotational vibration are identical for both rotor masses, allowing differential measurement to eliminate these coupling-induced interference modes while preserving the Coriolis effect signal
Solution Approach 2:
The patent converts the potentially harmful coupling between rotor masses into a beneficial differential measurement opportunity. By arranging masses symmetrically, the coupling effects become identical for both rotor masses, allowing the system to use differential measurement techniques to reject these coupling-induced interference signals while maintaining sensitivity to external rotational movements
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 design enhances measurement accuracy, reduces vibrational sensitivity, and minimizes installation space, enabling more versatile and robust 3-axis rotation rate sensors capable of detecting rotational movements without false signals from external accelerations.
Implementation Method 1
the two rotor masses and the four seismic masses are mirror symmetrical with respect to a plane of symmetry passing through the center of the rotor masses
Data Source
AI summary
A micromechanical component for a rotation rate sensor. The micromechanical component includes two rotor masses, mirror symmetrical with respect to a first plane of symmetry aligned perpendicularly to a substrate surface and passing through the center of the two rotor masses, which may be set in rotational vibrating motion about rotational axes aligned perpendicularly to the substrate surface, and four seismic masses, mirror symmetrical with respect to the first plane of symmetry, deflectable in parallel to the first plane of symmetry using the two rotor masses set in their respective rotational vibrating motion. The first rotor mass and a first pair of the four seismic masses connected thereto are mirror symmetrical to the second rotor mass and to a second pair of the four seismic masses connected thereto with respect to a second plane of symmetry aligned perpendicularly to the substrate surface and to the first plane of symmetry.