MEMS Gyroscope Dual-Mode Proof Mass for Two-Axis Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing MEMS gyroscopes struggle to simultaneously sense rotation about two perpendicular axes using a single proof mass and sense mode.
Innovation Solution
A MEMS gyroscope design that utilizes a single proof mass to oscillate in two orthogonal drive modes at different frequencies, allowing simultaneous sensing of rotations about two perpendicular axes by demodulating the oscillation signals at distinct frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single proof mass and sense mode are used, then device complexity is reduced, but the ability to simultaneously sense rotation about two perpendicular axes is compromised
Solution Approach 1:
The patent applies dynamics by enabling the single proof mass to oscillate in two different drive modes at different frequencies. The proof mass transitions between radial oscillation in the first drive mode and tangential oscillation in the second drive mode, allowing the system to sense rotations about two perpendicular axes sequentially. This dynamic switching capability resolves the contradiction by making the single proof mass adaptable to multiple sensing functions without requiring multiple physical proof masses.
Solution Approach 2:
The patent utilizes parameter changes by varying the oscillation frequency and mode of the proof mass. The first drive mode operates at a first frequency with radial oscillation, while the second drive mode operates at a second frequency with tangential oscillation. By changing these parameters, the system enables simultaneous sensing of rotations about two perpendicular axes using a single proof mass, thereby reducing device complexity while maintaining versatility.
2Measurement precision
If multiple proof masses are used to sense rotation about two perpendicular axes, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing a single proof mass that can perform multiple sensing functions. The proof mass is configured to oscillate in two different drive modes (radial and tangential) at different frequencies, enabling it to sense rotations about both the first and second perpendicular axes. This multi-functional capability eliminates the need for multiple separate proof masses, thereby improving measurement precision while reducing device complexity.
Solution Approach 2:
The patent uses dynamics to enable a single proof mass to dynamically switch between different oscillation modes and frequencies for sensing different axes. The proof mass can be driven radially at a first frequency for sensing one axis and tangentially at a second frequency for sensing the other axis. This dynamic adaptability allows the single proof mass to replace multiple static proof masses, maintaining measurement precision while simplifying the device structure.
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
Enables simultaneous sensing of angular rates around two perpendicular axes, improving the accuracy and efficiency of angular rate detection.
Implementation Method 1
MEMS gyroscopes infer angular rate by measuring the Coriolis force exerted on an oscillating proof mass. As the MEMS gyroscope rotates around a rotation axis, which is perpendicular to both the drive and sense axes, the Coriolis force drives oscillation of the proof mass along the sense axis.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to the field of microelectromechanical systems (MEMS) gyroscopes. The MEMS gyroscope of the present invention drives oscillation of at least one proof mass in a primary drive mode at a first frequency and in a secondary drive mode at a second frequency, different to the first frequency. The primary drive mode and secondary drive mode are orthogonal. Sense circuitry measures oscillation of the at least one proof mass in a sense mode, which is orthogonal to the primary drive mode and the secondary drive mode, in order to determine the angular rate of rotation of the MEMS gyroscope about sense axes parallel to the movement of the at least one proof mass in the primary and secondary drive modes.