MEMS Rate Sensor Mass Segmentation for Stability
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Solution Overview
Problem
Existing micro rate of rotation sensors using MEMS technology are sensitive to external forces and temperature, leading to false measurements and require a large substrate area, making them unstable and inaccurate.
Innovation Solution
A micro rate of rotation sensor design featuring masses connected by springs, where driving masses oscillate in the X-direction, indirectly driving X-Y sensor masses to oscillate in the X-Y plane, reducing sensitivity to external forces and temperature effects while maintaining high measurement accuracy with a compact structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If masses are driven to oscillate in conventional MEMS rate of rotation sensors, then measurement capability is achieved, but sensitivity to external forces and temperature increases causing false measurements
Solution Approach 1:
The sensor masses are divided into multiple segments (first mass, second mass, third mass, fourth mass) arranged in a specific pattern. Each mass segment responds to different components of rotational motion, and their combined response provides the measurement while canceling out external force effects and temperature variations through differential measurement.
Solution Approach 2:
The sensor uses more mass elements than the minimum required for a single-axis measurement. By implementing four mass segments instead of one or two, the sensor achieves partial measurements from each segment that, when combined, provide both high accuracy and immunity to external disturbances through redundant measurement paths.
2Measurement precision
If conventional MEMS sensor structures are used, then measurement function is achieved, but large substrate area is required
Solution Approach 1:
The mass segments are arranged in a nested or compact configuration where the first, second, third, and fourth masses are positioned to overlap or interlock in the planar view. This nesting allows multiple functional masses to occupy a smaller substrate area while maintaining their individual measurement capabilities and structural integrity.
Solution Approach 2:
The sensor design transitions from a conventional planar arrangement to a more three-dimensional spatial configuration. The masses are positioned at different heights or depths relative to each other, allowing them to be packed more efficiently on the substrate. This dimensional reorganization reduces the footprint while preserving the measurement functionality.
3Stability of the object's composition
If masses are supported on substrate with conventional mounting, then structural support is achieved, but stability against external influences and temperature effects deteriorates
Solution Approach 1:
The four mass segments are positioned and configured to act as counterweights to each other. When external forces or temperature changes cause deformation, the differential arrangement of the masses creates opposing responses that cancel each other out in the measurement signal, maintaining reliability despite structural disturbances.
Solution Approach 2:
The sensor configuration inherently provides feedback through the interconnected arrangement of the four mass segments. The motion of each mass segment influences the others through their mechanical coupling, creating a self-correcting system that maintains stable operation and compensates for external disturbances through the collective behavior of the mass array.
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 sensor achieves stable support of masses, reducing the impact of external influences and temperature on measurement results, ensuring high accuracy and low space requirements for detecting rotations about orthogonal axes.
Implementation Method 1
drive elements in order to excite the masses to oscillate in the X-direction, so that Coriolis forces act on the masses in case of a deflection of the substrate
Implementation Method 2
The masses (11, 8, 12) are attached to at least one adjacent mass or to at least one anchor by means of springs
Data Source
AI summary
The present invention relates to a method for operating a rotation sensor for detecting a plurality of rates of rotation about orthogonal axes (x,y,z). The rotation sensor comprises a substrate, driving masses, X-Y sensor masses, and Z sensor masses. The driving masses are driven by drive elements to oscillate in the X-direction. The X-Y sensor masses are coupled to the driving masses, and driven to oscillate in the X-Y direction radially to a center. When a rate of rotation of the substrate occurs about the X-axis or the Y-axis, the X-Y sensor masses are jointly deflected about the Y-axis or X-axis. When a rate of rotation of the substrate occurs about the Z-axis, the X-Y sensor masses are rotated about the Z-axis, and the Z sensor masses are deflected substantially in the X-direction.