Gyro Sensor Circuit Fault Detection With Injected Test Tones
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Solution Overview
Problem
Gyroscopes face challenges in maintaining sensitivity and accuracy due to sensitivity shifts and drifts over their lifespan, making real-time fault detection difficult, especially when deployed in the field, and existing closed-loop systems are prone to inaccuracies and false alarms from deteriorating electronic circuits.
Innovation Solution
A gyro sensor circuit with integrated RF sense, sense base band, forced-to-rebalance, and quadrature cancellation loop paths for continuous monitoring, using safety measure flags to detect deviations and identify abnormal components, ensuring high performance and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed-loop feedback electronics are used to control gain and linearity, then sensitivity and performance are improved, but false alarms and inaccuracies occur when electronic circuits deteriorate over time
Solution Approach 1:
The system segments the monitoring function by separating the sensing path from the feedback path, allowing independent monitoring of each. The sensing path monitors the actual gyroscope output while the feedback path monitors the feedback signal, enabling detection of abnormalities in either path without affecting the other.
Solution Approach 2:
A test tone signal is introduced as an intermediary to monitor the feedback path. This test tone is injected into the feedback path and its presence/absence or amplitude changes indicate abnormalities in the feedback electronics, allowing detection of circuit deterioration without affecting the actual sensing operation.
2Reliability
If continuous monitoring is implemented to detect circuit deterioration, then reliability is improved, but system complexity increases
Solution Approach 1:
The monitoring function is merged with the existing feedback path by utilizing the same electronic components and signal paths already present in the closed-loop system. The test tone monitoring is combined with the existing feedback electronics, eliminating the need for separate dedicated monitoring hardware.
Solution Approach 2:
The system performs self-diagnosis by using its own feedback path and electronics to monitor itself. The test tone is processed through the existing feedback circuitry, and the system automatically detects abnormalities without requiring external monitoring equipment or complex additional circuitry.
3Measurement precision
If sensitivity calibration is performed using known rotary stimuli, then measurement accuracy is improved, but recalibration becomes difficult when deployed in the field
Solution Approach 1:
A test tone signal serves as an intermediary for monitoring the feedback path, replacing the need for physical rotary stimuli for recalibration. This test tone can be electronically injected and measured without requiring external mechanical calibration equipment or known rotary inputs.
Solution Approach 2:
The mechanical calibration process using rotary stimuli is replaced with an electronic test tone-based monitoring system. Instead of applying physical rotational forces for calibration, the system uses electronic test signals that can be injected and measured electrically, eliminating the need for mechanical calibration equipment in the field.
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
Enables real-time detection and identification of faulty components in gyro sensor circuits, maintaining high performance by continuously monitoring and correcting deviations from target ranges, thus preventing inaccuracies and false alarms.
Implementation Method 1
a first chopper comprising a chopping switch, and configured to chop a tone signal at a chopping frequency to generate a chopped tone signal
Implementation Method 2
a first RF amplifier to amplify the combined signal
Implementation Method 3
a first demodulator configured to mix the combined RF sensing and tone signal with a local oscillator (LO) signal to output a demodulated signal
Implementation Method 4
a first analog-to-digital converter (ADC) configured to sample the demodulated signal to output a digitized signal
Implementation Method 5
a first digital signal processor (DSP) to extract a signal at chopping frequency from the digitalized signal
Implementation Method 6
a feedback path configured to feed back a portion of the demodulated signal to the gyro sensor as a feedback signal
Implementation Method 7
a modulator to upconvert the feedback signal to the resonant frequency of the gyro sensor (f res)
Data Source
AI summary
A gyro sensor circuit includes a gyro sensor generating a radio frequency (RF) sensing signal according to an angular movement of the gyro sensor, and an RF sensing path comprising a first chopper comprising a chopping switch, and configured to chop a tone signal at a chopping frequency to generate a chopped tone signal, an adder configured to insert the chopped tone signal to the RF sensing signal to produce a combined RF sensing and tone signal, and a first demodulator configured to mix the combined RF sensing and tone signal with a local oscillator (LO) signal to output a demodulated signal. The tone signal may be the LO signal. The gyro sensor circuit further comprises a sense base band path comprising a first analog-to-digital converter configured to sample the demodulated signal to output a digitized signal, and a first digital signal processor to extract various signals to be analyzed.