Decoupled Three-Axis MEMS Gyroscope Mass Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing three-axis MEMS gyroscopes suffer from weak coupling of the gyroscope mass structure, leading to coupled sense modes and excessive errors in angular velocity detection.
Innovation Solution
A fully decoupled three-axis MEMS gyroscope design featuring a unique anchor point unit, driving unit, and sensing unit, with symmetrically arranged X, Y, and Z mass blocks and decoupling members, allowing for independent detection of angular velocities along each axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional three-axis MEMS gyroscope structure is used, then the device can detect angular velocity along three axes, but the sense modes of the three axes become coupled to each other resulting in excessive gyroscope errors
Solution Approach 1:
The mass structure is segmented into three independent sets of mass blocks (X-axis: 2 mass blocks, Y-axis: 2 mass blocks, Z-axis: 4 mass blocks), each set dedicated to a specific axis. The decoupling members further segment the connection paths, ensuring that motion in one axis does not couple into other axes. This segmentation allows independent detection along each axis while maintaining three-axis functionality.
Solution Approach 2:
Decoupling members are introduced as intermediary elements between the mass blocks and the drive mode structure. These decoupling members act as mediators that allow necessary mechanical connections while blocking the transmission of unwanted vibrational coupling between axes. The decoupling members selectively transmit only the intended axis of motion while isolating other axes, thereby preventing error propagation.
2Ease of manufacture
If the gyroscope mass structure uses weak coupling, then the structure is simpler to manufacture, but the sense modes become coupled resulting in error superposition
Solution Approach 1:
The coupling characteristics are made non-uniform across different parts of the structure. Strong coupling is provided locally between drive mode and sense mode for the intended axis through drive members, while weak or decoupled connections are provided locally between different sense modes through decoupling members. This local differentiation of coupling strength allows simple manufacturing while preventing error coupling.
3Measurement precision
If differential detection is implemented for all three axes, then acceleration impulse and quadrature error are reduced, but the structural complexity increases
Solution Approach 1:
Multiple functions are merged into the decoupling members: they provide mechanical support, enable differential motion for error reduction, and simultaneously prevent coupling between axes. The symmetric arrangement of mass blocks and decoupling members combines structural integrity with functional requirements, achieving error reduction without proportionally increasing complexity.
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 achieves independent detection of angular velocities for each axis, effectively reducing the influence of acceleration impulses and quadrature errors, thereby improving the precision and stability of the gyroscope.
Implementation Method 1
When an angular velocity Ω is applied, the gyroscope transfers energy to the sensitive mode due to the Coriolis Effect, causing a vibrating disk to swing out-of-plane under relative drive.
Implementation Method 2
one end of each driving member close to the center of the rectangle is elastically connected to the central anchor point subunit
Data Source
AI summary
Provided is a fully decoupled MEMS gyroscope, including an anchor point unit, a sensing unit elastically connected to the anchor point unit, and a driving unit configured to drive the sensing unit to move. The anchor point unit includes a center anchor point subunit located at a center of a rectangle and four side anchor points. The driving unit includes four driving members located on four sides of the rectangle. The sensing unit includes two X mass blocks symmetrically arranged in two avoiding intervals, two Y mass blocks symmetrically arranged in the other two avoiding intervals, four Z mass blocks respectively located at an outer side of each driving member, and four Z detection decoupling members respectively located at an outer side of each Z mass block. The X mass blocks and the Y mass blocks are respectively connected to each side anchor point.