MEMS Multiaxial Angular Rate Sensor with Synchronized Driving Rings
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Solution Overview
Problem
Conventional MEMS three-axis angular rate sensors are bulky due to independent driving circuits for each axis, leading to crosstalk interference and reduced sensing quality.
Innovation Solution
A MEMS multiaxial angular rate sensor design with independent driving structures in at least two axes, where a third driving structure is interactively actuated to synchronize motions and reduce timing asynchronicity and amplitude differences, using pendulum masses to store oscillation energy and stabilize oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three independent uniaxial angular rate sensors are used to measure angular rate in three orthogonal directions, then measurement precision is improved, but device volume increases and crosstalk interference occurs
Solution Approach 1:
The patent merges three independent uniaxial angular rate sensors into a single integrated multiaxial sensor structure. The first, second, and third driving and sensing structures are combined on one substrate with shared proof masses and driving structures, reducing the overall device volume while maintaining the ability to measure angular rate in three orthogonal directions simultaneously
Solution Approach 2:
The integrated sensor structure performs multiple functions within a single device. The first driving and sensing structure measures angular rate in the first direction, the second measures in the second direction, and the third measures in the third direction, all within one compact sensor that serves multiple measurement purposes simultaneously
2Measurement precision
If three independent uniaxial angular rate sensors are used, then measurement precision is improved, but crosstalk interference increases
Solution Approach 1:
The patent segments the sensor into distinct first, second, and third driving and sensing structures, each dedicated to measuring angular rate in specific orthogonal directions. This segmentation with dedicated proof masses and driving structures for each axis reduces mechanical coupling and crosstalk interference between axes while maintaining comprehensive measurement capability
3Volume of moving object
If a mass sharing design is used to reduce volume, then device volume decreases, but motion interference causes crosstalk among axes
Solution Approach 1:
The patent applies local quality by providing dedicated proof masses and driving structures for each axis within the integrated sensor. The first proof mass is dedicated to the first driving and sensing structure, the second proof mass to the second structure, and the third proof mass to the third structure, ensuring that each axis has its own localized sensing elements that prevent motion interference and crosstalk while maintaining compact overall volume
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 reduced bulkiness, improved sensing quality by minimizing crosstalk and synchronizing motions, enhancing the accuracy and efficiency of angular rate detection.
Implementation Method 1
the first driving comb pair structure drives the first driving ring to perform periodical rotation motion
Implementation Method 2
the second driving comb pair structure drives the second driving ring to perform periodical rotation motion
Implementation Method 3
the first driving ring and the second driving ring actuate the third driving ring to perform periodical rotation motion
Implementation Method 4
the interactive-actuation design of the pendulum masses of the third driving structure is used to synchronize the motions thereof and store the oscillation energy of the proof mass
Implementation Method 5
a coupling structure connected with the structure for stabilizing the structure and reducing the oscillation in the unnecessary directions
Implementation Method 6
If a mass moves along a direction and is applied to rotational angular speed in an axial direction different from moving direction, the mass will experience a force in the direction that is orthogonal to both the moving direction and the rotating axial direction because of the Coriolis Effect
Data Source
AI summary
A MEMS multiaxial angular rate sensor includes a substrate and a MEMS wafer layer correspondingly deposited and parallel to each other, and a plurality of anchors coupled to the MEMS wafer layer and fixing the MEMS wafer layer onto the substrate. The MEMS wafer layer includes at least two drive-sensing structures, a third driving ring and two pendulum masses. Each of the drive-sensing structures includes a driving ring, a plurality of driving comb pair structures and a plurality of sensing proof masses respectively coupled to the corresponding driving ring. A third driving ring is coupled to and deposited between the two driving rings of the two drive-sensing structures. In a driving mode, those driving comb pair structures drive the corresponding driving rings to perform periodical rotation motions, and the two driving rings in periodical rotation motions further actuate the third driving ring to perform periodical rotation motion together. Two pendulum masses are respectively coupled to the third driving ring and deposited at opposite two sides of the third driving ring.