Balanced 3-Axis Gyroscope Architecture for Vibration Rejection
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Solution Overview
Problem
Conventional MEMS vibratory rate gyroscopes fail to adequately reduce sensitivity to vibration, part-to-part coupling, levitation force-induced in-phase offset shift, and sensitivity to package stress.
Innovation Solution
A 3-axis gyroscope architecture with balanced drive and sense components, stress isolation frame, and mechanical coupling to minimize vibration and part-to-part coupling, featuring inner and outer frame gyroscopes, drive shuttles, and proof masses configured for anti-phase motion to achieve linear and angular momentum balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional vibratory rate MEMS gyroscopes are used, then basic angular velocity sensing is achieved, but sensitivity to vibration and part-to-part coupling remains high
Solution Approach 1:
The gyroscope is divided into multiple independent proof mass assemblies (first and second proof masses) that can be independently controlled and sensed. Each proof mass assembly operates as a separate vibratory rate gyroscope unit, allowing independent vibration rejection control while maintaining overall angular velocity sensing functionality.
Solution Approach 2:
A control mechanism acts as an intermediary between the drive system and the proof mass assemblies, enabling active vibration rejection. The control mechanism receives vibration signals and generates compensating forces to cancel out vibration effects on the proof masses, thereby reducing sensitivity to vibration while preserving sensing accuracy.
2Ease of manufacture
If conventional MEMS gyroscope structures are used, then manufacturing is simplified, but levitation force induced in-phase offset shift occurs
Solution Approach 1:
The gyroscope employs counterbalancing proof mass assemblies that generate opposing levitation forces to cancel out unwanted in-phase offset shifts. The second proof mass assembly is positioned and configured to produce levitation forces that counteract those from the first proof mass assembly, thereby stabilizing the overall offset while maintaining a relatively simple structural configuration.
3Device complexity
If conventional single-axis gyroscope architectures are used, then device complexity is low, but cross-axis sensitivity and part-to-part coupling cannot be adequately reduced
Solution Approach 1:
The gyroscope architecture is segmented into multiple proof mass assemblies (first and second proof masses) that can be independently controlled. This segmentation allows the system to reject vibrations and coupling effects along multiple axes simultaneously while maintaining manageable complexity through modular design and independent control mechanisms.
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
Improves offset stability, vibration rejection, and reduces cross-axis sensitivity by minimizing levitation force-induced offset shifts and package stress, enhancing the accuracy of angular velocity sensing.
Implementation Method 1
one or more inner frame gyroscopes configured to sense a first component of angular velocity associated with the MEMS device, two or more drive shuttles coupled to the one or more inner frame gyroscopes, two or more additional proof masses coupled to the inner frame gyroscopes, and configured to be driven into linear and angular momentum balanced anti-phase motion
Implementation Method 2
Vibratory rate gyroscopes broadly function by driving the sensor into a first motion and measuring a second motion of the sensor that is responsive to both the first motion and the angular velocity to be sensed
Data Source
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AI summary
The subject disclosure provides exemplary 3-axis (e.g., GX, GY, and GZ) linear and angular momentum balanced vibratory rate gyroscope architectures with fully-coupled sense modes. Embodiments can employ balanced drive and/or balanced sense components to reduce induced vibrations and/or part to part coupling. Embodiments can comprise two inner frame gyroscopes for GY sense mode and an outer frame or saddle gyroscope for GX sense mode and drive system coupling, drive shuttles coupled to the two inner frame gyroscopes or outer frame gyroscope, and four GZ proof masses coupled to the inner frame gyroscopes for GZ sense mode. Components can be removed from an exemplary overall architecture to fabricate a single axis or two axis gyroscope and/or can be configured such that a number of proof-masses can be reduced in half from an exemplary overall architecture to fabricate a half-gyroscope. Other embodiments can employ a stress isolation frame to reduce package induced stress.