Delta-Sigma Filter Frequency Matching for Yaw Rate Sensor Stability
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Solution Overview
Problem
Yaw rate sensors face challenges in maintaining precise resonance frequency alignment between the secondary mass and the primary resonant frequency due to manufacturing variations and temperature changes, leading to fluctuations that affect signal-to-noise ratio and stability, particularly in closed control loops.
Innovation Solution
A method involving a frequency adjustment circuit that evaluates the noise spectrum of a delta-sigma modulator's output in symmetric frequency bands around the primary resonant frequency, generating an adjustment signal to correct the secondary resonance frequency using the spring-softening effect, allowing for continuous adjustment during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the secondary resonance frequency is adjusted to match the primary resonant frequency, then the signal-to-noise ratio is improved, but the device complexity increases due to additional frequency adjustment circuitry
Solution Approach 1:
The system automatically adjusts the secondary resonance frequency using a feedback mechanism that monitors the noise spectrum and generates adjustment signals without external intervention. The frequency adjustment circuit self-regulates to maintain optimal frequency matching between secondary and primary resonances, eliminating the need for manual calibration while improving signal-to-noise ratio.
Solution Approach 2:
The invention implements a closed-loop feedback system where the noise spectrum is continuously monitored and compared against reference values. Based on the spectral analysis, the system automatically generates feedback signals to adjust the secondary resonance frequency, ensuring continuous optimization of the signal-to-noise ratio without requiring complex external control mechanisms.
2Stability of the object's composition
If the resonance frequency alignment is maintained under temperature changes, then the stability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The system transitions from a static frequency matching approach to a dynamic adjustment mechanism that continuously adapts the secondary resonance frequency in response to environmental changes. The frequency adjustment circuit actively compensates for temperature-induced frequency drifts, maintaining optimal alignment between secondary and primary resonances without requiring extremely tight manufacturing tolerances.
Solution Approach 2:
The invention utilizes adjustable electrical parameters (capacitance or inductance values) in the secondary resonance circuit to dynamically change the resonance frequency. By varying these electrical parameters through the adjustment circuit, the system compensates for temperature effects and maintains frequency alignment, reducing the stringency of manufacturing precision requirements.
3Adaptability or versatility
If continuous frequency adjustment is implemented during operation, then the adaptability is improved, but the loss of energy increases due to continuous circuit operation
Solution Approach 1:
The frequency adjustment circuit operates periodically rather than continuously, performing spectral analysis and adjustments at intervals sufficient to track frequency drifts caused by temperature changes. This periodic operation maintains frequency adaptability while significantly reducing energy consumption compared to continuous adjustment mechanisms.
Solution Approach 2:
The system implements frequency adjustment only when necessary, triggered by detected frequency mismatches or temperature changes. Rather than continuously adjusting, the system activates the adjustment circuit selectively to maintain frequency alignment, achieving adaptability with minimal energy expenditure by avoiding unnecessary adjustment operations.
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 enables precise and continuous frequency adjustment with minimal additional circuit complexity, improving signal-to-noise ratio and stability by ensuring the secondary resonance frequency aligns with the primary resonant frequency, even under temperature changes.
Implementation Method 1
generating an adjustment signal to correct the secondary resonance frequency using the spring-softening effect
Implementation Method 2
This involves reducing the quantization noise generated at the output. The quantization noise is suppressed in the signal band and shifted to other frequencies by filters provided within the modulator
Implementation Method 3
If the sensor undergoes rotation about an axis perpendicular to the primary oscillation or primary motion, the movement of the primary oscillation results in a Coriolis force that is proportional to the measured quantity, i.e., the angular velocity
Implementation Method 4
The primary mass, in which the secondary mass is suspended, is set into constant oscillation at its resonant frequency, for example, by electrostatic actuation
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The present invention relates to a method for adjusting the resonant frequency of a first filter of a closed-loop control system comprising a delta-sigma modulator to a predetermined frequency, the method comprising the following steps: feeding an output signal of the delta-sigma modulator into a frequency matching circuit, determining a first noise spectrum of the output signal of the delta-sigma modulator in a first frequency band and a second noise spectrum of the output signal of the delta-sigma modulator in a second frequency band in the frequency matching circuit, wherein the first frequency band and the second frequency band are arranged symmetrically around the predetermined frequency, comparing the first noise spectrum in the first frequency band with the second noise spectrum in the second frequency band, generating a matching signal that effects a frequency adjustment of the resonant frequency.if the first noise spectrum differs from the second noise spectrum, and output the matching signal from the frequency matching circuit to a control input of the first filter to adjust the resonant frequency in response to the comparison result.