Vibrating Structure Angular Rate Sensor Phase Stabilization
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Solution Overview
Problem
Existing vibrating structure angular rate sensors face challenges in maintaining high precision control of resonators due to amplitude changes, which affect phase stability and accuracy, particularly with temperature variations affecting the quality factor.
Innovation Solution
Incorporating a signal generator with an integrating circuit that generates a phase change suppressing signal, such as a triangular waveform, to stabilize the phase of drive signals, ensuring precise control of resonators even with amplitude changes, and reducing phase-related errors in angular rate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rectangular wave signal is used to drive the resonator, then the resonator can be driven with a constant amplitude, but the phase of the drive signal changes with amplitude changes due to slew rate limitations
Solution Approach 1:
The patent transitions from a static rectangular wave signal to a dynamic triangular wave signal where the slope is continuously adjusted. This dynamic waveform adapts to amplitude changes while maintaining a constant time to reach the midpoint, thereby stabilizing the phase of the drive signal despite amplitude variations caused by quality factor changes.
2Adaptability or versatility
If the quality factor changes with temperature or time, then the amplitude of the drive signal must be adjusted, but this causes phase shifts that reduce control precision
Solution Approach 1:
The patent changes the waveform parameter from rectangular to triangular, and specifically adjusts the slope parameter of the triangular wave. By controlling the slope to vary inversely with amplitude, the system maintains a constant time to reach the midpoint (50% amplitude point), thereby eliminating phase shifts that would otherwise occur when adapting to quality factor changes.
3Speed
If a fast rising speed signal is input into the amplifier, then the signal can respond quickly, but the slew rate limitation causes the output waveform to become trapezoidal with amplitude-dependent phase shifts
Solution Approach 1:
Instead of using a fixed rectangular wave with infinitely fast rising edges, the patent employs a triangular wave with a dynamically controlled slope. This slope is adjusted based on the desired amplitude, ensuring that the time to reach the midpoint remains constant. This dynamic adaptation eliminates the amplitude-dependent phase shifts caused by slew rate limitations while still achieving fast response.
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 solution enables high precision control of resonators and reduces errors in angular rate detection by stabilizing the phase of drive signals, even when the amplitude changes, thereby improving the accuracy and reliability of the sensor.
Implementation Method 1
the primary-side control circuit vibrates (resonates) a resonator with a constant amplitude along one axial direction
Implementation Method 2
the secondary-side control circuit applies a suppressing force (vibration) to the resonator so as to suppress a vibration generated in the resonator along another orthogonal axial direction to one axial direction due to a Coriolis force (angular rate)
Data Source
AI summary
In a vibrating structure angular rate sensor, a signal generator generates a phase change suppressing signal in which a phase change according to an amplitude of a rectangular wave signal generated by at least one of a first modulator and a second modulator is suppressed.