MEMS Microgyroscope Three-Axis Rotation Detection
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Solution Overview
Problem
Current microgyroscopes require multiple devices to determine rotational motions about three perpendicular axes, leading to high costs and complex control and evaluation, with existing designs facing challenges in achieving accurate measurements due to mutual interference of component motions.
Innovation Solution
A microelectromechanical system (MEMS) microgyroscope with oscillating masses on a silicon substrate, utilizing springs and anchorings for drive elements and sensor elements to detect Coriolis forces, allowing for compact, simple designs that accurately measure yaw rates about one, two, or three axes by optimizing mass movability and sensor placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three separate microgyroscopes are used to determine rotational motions about three perpendicular axes, then measurement capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines three separate microgyroscope functions into a single integrated device. Multiple oscillating masses are arranged on a common substrate, with each mass sensitive to rotation about a different axis. The sensor housing integrates all three measurement functions, eliminating the need for three separate devices while maintaining full three-axis rotational motion detection capability.
Solution Approach 2:
The single microgyroscope device performs multiple functions by detecting rotational motions about all three perpendicular axes simultaneously. Each oscillating mass is designed to respond to Coriolis forces generated by rotation about a specific axis, allowing the device to universally measure rotational motion in three-dimensional space without requiring separate specialized sensors for each axis.
2Measurement precision
If oscillating masses are arranged to detect all three axes simultaneously, then measurement capability is improved, but mutual interference between components increases
Solution Approach 1:
The device segments the measurement function by assigning each oscillating mass to detect rotation about a specific axis independently. The first mass detects rotation about the first axis, the second mass detects rotation about the second axis, and the third mass detects rotation about the third axis. This segmentation isolates the measurement functions, reducing mutual interference between components while maintaining simultaneous three-axis detection capability.
Solution Approach 2:
Each oscillating mass is designed with specific local properties optimized for detecting Coriolis forces generated by rotation about its designated axis. The masses are positioned and suspended to maximize sensitivity to their respective axis of rotation while minimizing sensitivity to rotations about other axes, thereby reducing cross-axis interference and improving measurement precision.
3Measurement precision
If masses are made movable in multiple directions for three-axis detection, then detection accuracy is improved, but difficulty in determining deflections increases
Solution Approach 1:
The patent extracts and measures only the relevant deflection components for each axis independently. Each oscillating mass is configured so that its primary deflection response corresponds to rotation about a specific axis. By focusing measurement on these extracted, axis-specific deflection components rather than attempting to measure all possible motion components, the device simplifies the measurement process while maintaining high detection accuracy for three-axis rotational motion.
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 detection accuracy and stability, reduces interference, and allows for precise evaluation of yaw rates by decoupling secondary motions, resulting in a compact and reliable microgyroscope capable of detecting rotational motions about multiple axes.
Implementation Method 1
When the substrate rotates about a predetermined spatial axis, Coriolis forces result which cause the associated masses to be deflected in a defined direction
Implementation Method 2
At least some of these oscillating masses are attached to the substrate by means of springs and anchorings
Data Source
AI summary
A microgyroscope is used to determine rotational motions about at least one of three perpendicular spatial axes x, y, and z. The microgyroscope has a substrate (1) on which multiple masses (2x, 2y, 9) which oscillate parallel to the plane of the substrate (1) in an x-y plane are situated. Some of the oscillating masses (2x, 2y) are attached to the substrate (1) by means of springs and anchorings. Drive elements (4a, 4b) are used to maintain oscillating vibrations of the masses (2x, 2y, 9) which are subjected to Coriolis forces when the substrate (1) rotates about any given spatial axis. Sensor elements detect the deflections of the masses (2x, 2y, 9) due to the Coriolis forces generated. Some of the oscillating masses are x masses (2x) which are also deflectable along the z axis perpendicular to the substrate (1), by means of which they are able to detect yaw rates about the x axis, and/or some of the oscillating masses are y masses (2y) which are also deflectable along the z axis perpendicular to the substrate (1), by means of which they are able to detect yaw rates about the y axis, and/or others of the oscillating masses are z masses (9) which are also deflectable in the x-y plane, but perpendicular to their respective drive direction, by means of which they are able to detect yaw rates about the z axis.