MEMS Gyroscope Pilot Tone Injection for Parameter Characterization
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Solution Overview
Problem
Conventional MEMS gyroscopes face performance degradation due to manufacturing imperfections and run-time variations, which existing high-order observer and adaptive controller solutions are computationally expensive and analytically complex to implement.
Innovation Solution
A MEMS gyroscope system that uses pilot tone signals to dynamically measure and correct system parameters, such as plant Q, plant gain, and bias terms, by injecting and processing pilot tones within the quadrature channel, allowing for continuous monitoring and performance tuning without downtime or interference with normal operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high order observers and adaptive controllers are used to compensate for manufacturing imperfections and run-time variations, then gyroscope performance is improved, but computational complexity and implementation difficulty increase significantly
Solution Approach 1:
The patent transforms the complex control problem into a parameter estimation problem. Instead of using computationally intensive high-order observers and adaptive controllers, the system injects pilot tones and extracts system parameters (mass, stiffness, damping, coupling coefficients) by analyzing the response at known frequencies. This parameter-based approach dramatically reduces computational complexity while maintaining performance compensation capability.
Solution Approach 2:
The patent introduces pilot tones as intermediary test signals to characterize the gyroscope system. These known-frequency signals act as mediators between the input and output, allowing the system to extract transfer function parameters without requiring complex real-time computation. The pilot tones enable indirect measurement of system parameters that would otherwise require sophisticated observers.
2Measurement precision
If complex compensation algorithms are implemented to address manufacturing imperfections, then measurement precision is improved, but ease of operation deteriorates due to analytical complexity
Solution Approach 1:
The patent performs system characterization in advance by injecting pilot tones and extracting parameters before normal operation. The transfer function parameters are determined beforehand and stored, eliminating the need for complex real-time computation during actual gyroscope operation. This preliminary characterization simplifies the operational algorithm while maintaining high measurement precision through accurate parameter-based compensation.
3Reliability
If continuous monitoring of system parameters is implemented, then reliability is improved, but loss of time is incurred during traditional characterization methods
Solution Approach 1:
The patent enables continuous system parameter monitoring by injecting pilot tones during normal operation without interrupting the gyroscope's useful function. The pilot tone frequencies are chosen to be distinct from operational frequencies, allowing simultaneous characterization and measurement. This continuous monitoring approach eliminates downtime associated with traditional off-line characterization methods.
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 significantly reduces computational complexity and cost, enabling efficient extraction of key system parameters for improved gyroscope performance and health monitoring, while maintaining normal operation without interruptions.
Implementation Method 1
a sense resonator and a drive resonator that are configured to undergo oscillatory motion
Implementation Method 2
injecting and processing pilot tones within the quadrature channel
Data Source
AI summary
A microcontroller-based method and apparatus are described for generating one or more amplitude and frequency selectable low frequency pilot tone signals (PT) that are injected into an embedded MEMS sensor (110) and mixed signal ASIC (120) and then recovered at the microcontroller (140) to compute or measure various gyro parameters during operational use of the device with no down time or interference with normal operations.