MEMS Gyroscope Phase Error Correction Circuit
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Solution Overview
Problem
Microelectromechanical (MEMS) resonators in vibration-type gyroscopes are prone to manufacturing errors, leading to accuracy issues due to in-phase and quadrature bias errors, which are difficult to correct without pre-calibration and can increase manufacturing costs.
Innovation Solution
A vibration type gyroscope with a quadrature demodulator, offset canceller circuits, and a phase corrector that dynamically corrects phase errors by canceling DC offset components and calculating the quadrature phase error, allowing for accurate detection of angular velocity signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If MEMS resonators are used in vibration-type gyroscopes, then manufacturing cost and availability are improved, but manufacturing precision and accuracy deteriorate due to manufacturing errors
Solution Approach 1:
The patent applies preliminary action by performing phase correction calibration during the manufacturing process. The system pre-determines correction values for in-phase and quadrature phase errors through automated testing and stores these correction parameters in memory. This preliminary calibration compensates for manufacturing variations before the product reaches the customer, maintaining accuracy without requiring post-manufacturing adjustments.
Solution Approach 2:
The patent implements feedback mechanisms through automated test equipment that measures actual phase errors during manufacturing and feeds this information back to the correction system. The measured error values are used to dynamically adjust correction parameters, creating a closed-loop system that compensates for manufacturing variations and ensures consistent accuracy across production batches.
2Measurement precision
If pre-calibration is performed to correct phase errors, then accuracy is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies self-service by designing a system where the gyroscope automatically performs its own phase correction using pre-stored correction parameters. The correction logic is integrated into the device firmware, allowing it to self-compensate for manufacturing errors without requiring external calibration equipment or complex manual adjustment procedures during manufacturing.
Solution Approach 2:
The patent simplifies manufacturing by performing all necessary calibration measurements and storing correction parameters during an automated preliminary testing phase. This preliminary action eliminates the need for complex real-time calibration equipment during assembly, reducing manufacturing complexity while maintaining accuracy through pre-computed correction values.
3Measurement precision
If phase correction is performed dynamically during signal processing, then accuracy is improved, but processing time and complexity increase
Solution Approach 1:
The patent resolves this contradiction by performing the computationally intensive phase error measurement and correction parameter calculation during manufacturing as a preliminary action. The actual runtime operation only requires applying pre-computed correction values through simple arithmetic operations, maintaining high accuracy while minimizing processing time during actual gyroscope operation.
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-accuracy phase correction, reducing the influence of in-phase and quadrature errors, thereby improving the gyroscope's accuracy and reducing manufacturing costs by eliminating the need for pre-calibration.
Implementation Method 1
a resonator that includes a drive signal input terminal, a drive signal output terminal, and a sense signal output terminal for outputting a sense signal that is modulated by a drive signal input from the drive signal input terminal to the resonator
Implementation Method 2
a quadrature demodulator that quadratically demodulates the modulated sense signal
Data Source
AI summary
A gyroscope includes a MEMS sensor having a drive signal input terminal, a drive signal output terminal, and a sense signal output terminal. The gyroscope further includes a quadrature demodulator that demodulates a modulated sense signal and offset canceller circuits that cancel a direct current offset component included in an in-phase signal and a quadrature signal of the sense signal. The gyroscope has a quadrature error detector that detects a quadrature error based on the signals input from the offset canceller circuits and outputs an error signal. The gyroscope also has an IQ corrector circuit that receives the in-phase signal and the quadrature signal of the sense signal as inputs, and outputs a phase signal with a phase based on the error signal.