Vibration Gyro Bias Correction via Gain Alignment
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Solution Overview
Problem
Existing vibration gyros face challenges in achieving high bias stability due to differences in detection gains for zero degree components, which can result in insufficient correction accuracy when amplifying or attenuating signals.
Innovation Solution
A vibration gyro system that generates multiplexed drive signals using frequencies corresponding to resonance and different frequencies, with demodulation and feedback circuits to align detection gains and subtract parallel bias values from angular velocity signals, ensuring precise angular velocity detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If amplification or attenuation is applied to correct parallel bias values, then correction can be performed, but detection gain alignment becomes difficult to achieve accurately
Solution Approach 1:
The patent applies preliminary action by measuring and storing the detection gains for both angular velocity signals and parallel bias values before performing correction. This pre-measurement allows the system to normalize the gains during correction processing, eliminating the need for complex real-time gain alignment while maintaining high correction accuracy.
Solution Approach 2:
The patent implements feedback by continuously monitoring the detection gains and using this information to adjust the correction process. The stored detection gains are fed back into the correction algorithm to dynamically align the gains between angular velocity signals and parallel bias values, ensuring accurate correction without manual adjustment.
2Measurement precision
If multiple frequency drive signals are used to separate angular velocity and bias signals, then correction precision improves, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the drive signal into multiple frequency components - a first drive signal at a first frequency for exciting the drive mass, and a second drive signal at a second frequency for detecting parallel bias values. This frequency separation allows independent processing of angular velocity and bias components, improving detection precision while keeping the processing algorithm manageable through structured signal decomposition.
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 system achieves high bias stability by aligning detection gains for zero degree components, allowing for precise subtraction and correction of parallel bias values, thereby improving the accuracy of angular velocity signals.
Implementation Method 1
a sense mass configured to be displaced by a Coriolis force generated by an angular velocity
Implementation Method 2
The displacement of the movable mass can be determined based on, for example, capacitance change of a parallel plate-type capacitor or a comb-type capacitor
Data Source
AI summary
A vibration gyro having high bias stability, and a method of using the gyro for obtaining a precise angular velocity signal by correcting the bias. The gyro has: a drive signal generating part configured to generate a multiplexed drive signal; first and second demodulation circuits configured to generate first and second demodulation signals, respectively; first and second control circuits configured to generate first and second feedback amplitude signals, respectively; a feedback signal generating part configured to generate a first multiplexed feedback signal by multiplexing a first feedback signal obtained by modulating the first feedback amplitude signal at the first frequency, and at least one second feedback signal obtained by modulating the second feedback amplitude signal at the at least one second frequency; and a subtracter configured to output an angular velocity signal by subtracting the second feedback amplitude signal from the first feedback amplitude signal.