MEMS Gyroscope Oscillating Assembly for Acceleration Interference
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Solution Overview
Problem
The manufacturing of tuning fork type gyroscope MEMS devices faces challenges due to high-precision requirements and variations in manufacturing processes, leading to mismatched proof masses and support springs, which affect natural frequencies and sensitivity, causing interference from external accelerations and potential malfunctions.
Innovation Solution
The MEMS device incorporates an oscillating assembly with a first frame, torsional beams, and springs that connect the proof masses and frames in a specific configuration to control displacement and movement directions, ensuring opposite oscillations and resonance without fabrication-induced variations, enhancing sensitivity and reducing external acceleration interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If tuning fork type gyroscope structure is used to eliminate external acceleration interference, then external acceleration resistance is improved, but manufacturing precision requirements increase and sensitivity is affected due to fabrication variations
Solution Approach 1:
The device is divided into two separate oscillating systems (first and second oscillating systems) that can be independently manufactured and then combined. Each oscillating system includes its own proof mass, suspension beams, and springs, allowing for modular assembly that reduces the impact of fabrication variations on the overall matching between components.
Solution Approach 2:
A lever is introduced as an intermediary component that connects the first and second oscillating systems. The lever acts as a mediator that transfers and coordinates the motion between the two proof masses, enabling them to oscillate in opposite directions while accommodating minor manufacturing variations through the lever's mechanical coupling.
2Measurement precision
If high-precision manufacturing process is used to match proof masses and support springs, then natural frequency matching is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
By segmenting the device into modular oscillating systems that can be manufactured separately and assembled, the complexity of achieving precise frequency matching is reduced. Each module can be optimized independently, and the assembly process is simpler than attempting to manufacture the entire tuning fork structure as a single integrated component with precise matching requirements.
3Measurement precision
If proof masses are made to oscillate in opposite directions to achieve resonance, then sensitivity is improved, but manufacturing variations cause frequency mismatch and reduce performance
Solution Approach 1:
The oscillating system is segmented into two independently manufacturable proof masses that are coupled through a lever. This segmentation allows each proof mass to be manufactured with standard tolerances, and the lever coupling ensures they oscillate in opposite directions with consistent frequencies, achieving both high sensitivity and reliable frequency matching without requiring ultra-precise manufacturing.
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 configuration allows for improved sensitivity and reduced interference from external accelerations, ensuring accurate angular velocity sensing in orthogonal axes by maintaining consistent oscillation frequencies and directions, thus enhancing the performance and reliability of the MEMS device.
Implementation Method 1
The first springs connect the first frame and the third frame
Implementation Method 2
The torsional beams connect the first proof mass and the third frame
Implementation Method 3
When the MEMS gyroscope 30 is applied with an external angular velocity Wz along the z-axis, the Coriolis acceleration is generated along the y-axis
Implementation Method 4
the proof mass 31 is driven by the driving electrode 32 to oscillate at natural frequency along an x-axis
Data Source
AI summary
A micro-electro-mechanical-system (MEMS) device comprising two proof masses disposed in the first frame, such that the MEMS device with oscillating assemblies senses the angular velocity in the two axes, respectively. The MEMS device with oscillating assemblies further comprises a lever structure and two oscillating assemblies connecting at two opposite ends of the lever structure, such that the oscillating assemblies move in opposite directions synchronously. The MEMS device with oscillating assemblies further comprises a spring assembly connected between the proof mass and a movable electrode, restricting the proof mass to drive the movable electrode to only move in a specific direction.