Vibratory Gyroscope Scale Factor Stability Using Langasite
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Solution Overview
Problem
Vibrating gyroscopes face accuracy issues due to variations in the scale factor over time and temperature, which are not adequately accounted for, leading to uncertainties in determining the rate of angular rotation.
Innovation Solution
The use of piezoelectric monocrystal transducers, such as langasite, in the gyroscope to stabilize the scale factor by reducing variations with time and temperature, combined with PZT transducers for higher gain and signal-to-noise ratio, ensures accurate angular rotation measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional piezoelectric transducers (e.g., PZT) are used to drive and detect vibrations in the resonant structure, then the gain and signal-to-noise ratio are improved, but the scale factor varies significantly with temperature and time, reducing measurement accuracy
Solution Approach 1:
The patent applies different piezoelectric materials to different functional locations within the gyroscope. PZT transducers are used for drive electrodes where high gain is needed, while langasite monocrystal transducers are used for detection electrodes where temperature stability is critical. This spatial differentiation of material properties resolves the contradiction between gain and stability.
Solution Approach 2:
The gyroscope employs a composite transducer system combining two different piezoelectric materials (PZT and langasite monocrystal) with complementary properties. PZT provides high coupling coefficient and gain, while langasite provides low temperature coefficient of frequency. This composite approach allows the system to achieve both high signal-to-noise ratio and stable scale factor across temperature variations.
2Measurement precision
If the resonant structure is driven at higher amplitudes to improve signal detection, then the signal-to-noise ratio increases, but the scale factor variations with temperature become more pronounced, reducing measurement reliability
Solution Approach 1:
Detection transducers made from langasite monocrystal are strategically positioned at locations where temperature-induced scale factor variations have the greatest impact on measurement reliability. The langasite material's inherent low temperature coefficient compensates for these variations, maintaining reliable measurements even at higher vibration amplitudes.
3Measurement precision
If traditional spinning mass gyroscopes are used to achieve high measurement accuracy, then the orientation determination is reliable, but the device size increases and the system becomes more complex
Solution Approach 1:
The patent replaces the traditional mechanical spinning mass gyroscope with a vibratory gyroscope based on a resonant structure. Instead of relying on angular momentum from a spinning rotor, the system uses controlled vibrations of a resonant structure with piezoelectric transducers to detect rotation through Coriolis forces. This substitution dramatically reduces device complexity and size while maintaining measurement precision through the use of langasite monocrystal transducers for stable scale factor.
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 stability of the scale factor with langasite transducers allows for more precise determination of the rate of angular rotation, while PZT transducers enhance the signal-to-noise ratio, improving measurement accuracy and reliability across varying temperatures.
Implementation Method 1
a first set of drive electrodes is fixed to a pair of upper tines and a second set of pickoff electrodes is fixed to a pair of lower tines... at least one of the plurality of transducers comprises a piezoelectric monocrystal
Implementation Method 2
A vibrating gyroscope is a form of gyroscope in which a resonant structure is caused to vibrate
Data Source
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AI summary
A gyroscope comprising a resonant structure and a plurality of transducers configured to drive a vibrational mode in the resonant structure and detect vibrations of the resonant structure, wherein at least one of the plurality of transducers comprises a piezoelectric monocrystal.