Dual-Use Ring Resonator for Simultaneous Gyroscope and Accelerometer Sensing
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Solution Overview
Problem
Current inertial sensors require distinct gyroscopes and accelerometers to sense rotation and linear acceleration, leading to increased size, power consumption, and cost, as they necessitate separate excitation signals for linear acceleration detection.
Innovation Solution
A method utilizing a resonator mass driven at a resonance frequency with a set of drive-sense electrodes to derive linear acceleration by differencing signals from opposing or orthogonal pairs of electrodes, allowing for simultaneous detection of rotation and linear acceleration without additional excitation signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If distinct gyroscopes and accelerometers are paired to sense rotation and linear acceleration, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines gyroscope and accelerometer functions into a single resonator structure. The resonator mass is excited to operate in both gyroscope mode (detecting rotation via Coriolis effect) and linear sensing mode (detecting acceleration via translational motion) simultaneously or alternatively, eliminating the need for separate sensor devices while maintaining detection capabilities for both rotational and linear motion
Solution Approach 2:
The resonator structure is designed to perform multiple functions: it can be excited to detect rotation as a gyroscope, detect linear acceleration as an accelerometer, or operate in combined modes where distinct modes are excited simultaneously by distinct drive electrodes and detected by distinct sensing electrodes, making a single device universal for both sensing applications
2Measurement precision
If distinct excitation signals are used for linear acceleration detection, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The same resonator mass and electrodes used for gyroscope operation are utilized for linear acceleration sensing. The resonator can be excited in different modes using the same drive electrodes, and linear acceleration is detected by sensing the translational mode of the resonator mass without requiring additional excitation signals or separate accelerometer components, thereby reducing overall power consumption
3Measurement precision
If distinct excitation signals are used for linear acceleration detection, then measurement precision is improved, but device size increases
Solution Approach 1:
The patent merges the accelerometer and gyroscope into a single integrated resonator structure. The same resonator mass, drive electrodes, and sensing electrodes serve dual purposes for both linear acceleration and rotation detection, eliminating the need for separate sensor devices and reducing overall device footprint while maintaining detection precision for both motion types
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
This approach reduces the size, power requirements, and cost of sensors by enabling the detection of linear acceleration within a plane without distinct excitation signals, while maintaining the ability to sense rotation, thereby enhancing the efficiency and functionality of inertial sensors.
Implementation Method 1
driving the resonator mass at a resonance frequency of a first mode
Implementation Method 2
sensing the first mode amplitude by means of a set of at least two drive-sense electrodes
Implementation Method 3
deriving a linear acceleration based at least on a difference between signals of the at least two drive-sense electrodes
Data Source
AI summary
Methods and apparatus for sensing linear acceleration with a MEMS resonator mass, alone, or concurrently with sensing rate of rotation. A resonator mass, which may be a disk or a ring structure, is driven at a resonance frequency of one of the vibration modes of the resonator mass. The amplitude of vibration of that mode is sensed by a set of at least two drive-sense electrodes disposed at opposing positions across the resonator mass. A linear acceleration is derived based at least on a difference between signals of the opposing electrodes. Linear acceleration may be sensed in multiple orthogonal dimensions using multiple pairs of opposing electrodes. Rotation rate may be derived concurrently by sensing the energy coupled into an orthogonal mode of the resonator mass.