Micro-Machining Resonator Frequency Matching
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Solution Overview
Problem
Miniature vibratory gyroscopes face challenges in maximizing sensitivity and minimizing noise and bias drift due to the mismatched frequencies and mechanical quality factor of their wine-glass mode frequencies.
Innovation Solution
A method and apparatus for measuring and machining the principal stiffness axes of miniature electromechanical resonators to adjust their wine-glass mode frequencies by precisely removing or adding material at specific locations, using ultrasonic energy and micro-machining techniques to match the frequencies and enhance the mechanical quality factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing methods are used to fabricate miniature resonators, then production efficiency is maintained, but frequency matching precision and mechanical quality factor are insufficient
Solution Approach 1:
The patent applies preliminary action by performing frequency measurement and machining location calculation on the resonator before actual machining. The system measures the principal stiffness axes and wine-glass mode frequencies, calculates optimal machining locations based on energy concentration distribution, and prepares machining parameters in advance. This preliminary characterization enables precise frequency matching while simplifying the manufacturing process.
Solution Approach 2:
The patent applies local quality by concentrating machining operations at specific high-energy concentration locations rather than uniform machining. The system identifies regions with maximum kinetic and elastic energy concentration and performs localized material removal or addition. This targeted approach achieves frequency matching with minimal material removal, maintaining manufacturing efficiency while improving precision.
2Manufacturing precision
If material is removed from the resonator to adjust frequencies, then frequency matching is improved, but mechanical quality factor may be reduced
Solution Approach 1:
The patent applies local quality by performing machining only at locations with high energy concentration while avoiding low-energy regions. The system calculates and identifies specific angular coordinates where kinetic and elastic energy are concentrated, and confines material removal to these localized areas. This prevents unnecessary damage to low-stress regions, preserving the mechanical quality factor while achieving frequency matching.
Solution Approach 2:
The patent applies mechanics substitution by replacing traditional mechanical machining with ultrasonic vibration-assisted machining. The ultrasonic vibration reduces tool-workpiece contact forces and minimizes mechanical stress on the resonator during machining. This substitution enables precise material removal at high-energy locations while reducing the risk of inducing cracks or damage that would degrade the mechanical quality factor.
3Measurement precision
If precise frequency matching is achieved through machining, then sensitivity is enhanced, but production time increases
Solution Approach 1:
The patent applies preliminary action by performing automated frequency measurement, energy concentration calculation, and machining parameter optimization before actual machining. The system rapidly characterizes the resonator's principal stiffness axes and mode frequencies, then calculates optimal machining locations and depths using energy concentration analysis. This preliminary preparation enables precise frequency matching in a single machining pass, minimizing iterative adjustments and reducing total production time.
Solution Approach 2:
The patent applies self-service by implementing a closed-loop system where the resonator itself provides the information needed for its own frequency matching. The measurement system characterizes the resonator's actual frequency and stiffness properties, and this self-provided data is used to calculate the precise machining parameters needed. This eliminates the need for external trial-and-error adjustment processes, reducing time while maintaining precision.
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 allows for the precise matching of wine-glass mode frequencies and maximization of the mechanical quality factor, thereby enhancing the sensitivity, reducing noise, and minimizing bias drift in miniature vibratory gyroscopes.
Implementation Method 1
machining the one or more locations on the miniature electromechanical resonator to reduce the difference between the first and second wine-glass mode frequencies
Data Source
AI summary
A method of adjusting an operating parameter of a miniature electromechanical resonator comprises measuring angular coordinates of first and second principal stiffness axes of first and second wine-glass mode of the miniature electromechanical resonator, respectively; determining first and second wine-glass mode frequencies of the resonator being resonant frequencies of the first and second principal stiffness axes, respectively; calculating one or more locations on the resonator for machining to reduce a difference between the first and second wine-glass mode frequencies; and machining the one or more locations on the resonator to reduce the difference between the first and second wine-glass mode frequencies. An apparatus for adjusting an operating parameter of a miniature electromechanical resonator comprises a vibration actuator/detector configured to measure the locations of the first and second principal stiffness axes, and a micro-machining apparatus to add or remove material from the resonator for adjusting the operating parameter thereof.