Angular Rate Sensor Quadrature Error Compensation
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Solution Overview
Problem
Vibratory angular rate sensors face quadrature error due to manufacturing imperfections, leading to offset errors, reduced dynamic range, increased noise, and potential mechanical damage from electrostatic compensation techniques that require large voltages and precise phase matching.
Innovation Solution
Implementing quadrature compensation electrodes in reverse polarity with the sense electrodes associated with the drive mass, which reduces capacitance output and compensates for quadrature error without using electrostatic force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrostatic force is applied via quadrature compensation electrodes to compensate for quadrature error, then quadrature error is reduced, but large voltage is required and device complexity increases
Solution Approach 1:
The patent replaces the electrostatic force-based compensation system with a mechanical solution. Quadrature compensation masses are mechanically coupled to the drive mass through flexible support elements, allowing passive mechanical compensation of quadrature error without requiring large voltages or complex electrostatic control systems
Solution Approach 2:
The quadrature compensation masses automatically compensate for quadrature error through their mechanical coupling to the drive mass. The system self-regulates through the mechanical interaction between the compensation masses and drive mass, eliminating the need for external control systems or precise phase matching
2Measurement precision
If electrostatic force is applied for quadrature compensation, then quadrature error is reduced, but large voltage is required which increases energy consumption
Solution Approach 1:
The patent replaces the electrostatic force-based compensation system with a mechanical solution. Quadrature compensation masses are mechanically coupled to the drive mass through flexible support elements, allowing passive mechanical compensation of quadrature error without requiring large voltages or complex electrostatic control systems
Solution Approach 2:
The patent changes the compensation mechanism from electrical (electrostatic force requiring large voltage) to mechanical (passive mass-spring system). This parameter change eliminates the high voltage requirement and associated energy consumption while maintaining compensation effectiveness
3Measurement precision
If precise phase matching is required for electrostatic compensation, then quadrature error is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent replaces the electrostatic force-based compensation system with a mechanical solution. Quadrature compensation masses are mechanically coupled to the drive mass through flexible support elements, allowing passive mechanical compensation of quadrature error without requiring large voltages or complex electrostatic control systems
Solution Approach 2:
The quadrature compensation masses automatically compensate for quadrature error through their mechanical coupling to the drive mass. The system self-regulates through the mechanical interaction between the compensation masses and drive mass, eliminating the need for external control systems or precise phase matching
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
Effectively cancels quadrature error signals, enhancing the accuracy and reliability of angular rate sensors by minimizing mechanical motion and eliminating the need for precise phase matching and large voltage applications.
Implementation Method 1
The quadrature compensation electrodes are coupled in reverse polarity with the sense electrodes such that a first error component between the quadrature compensation electrodes and the drive mass substantially cancels a second error component between the sense electrodes and the sense mass
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An angular rate sensor (20) includes a drive mass (36) flexibly coupled to a substrate (22). A sense mass (42) is suspended above the substrate (22) is and flexibly connected to the drive mass (36) via flexible support elements (44). A quadrature compensation electrode (24) is associated with the drive mass (36) and a sense electrode (28) is associated with the sense mass (42). The drive mass (36) and the sense mass (42) oscillate together relative to a sense axis (50) in response to quadrature error. The quadrature error produces a signal error component (78) between the quadrature compensation electrode (24) and the drive mass (36) and a signal error component (76) between the sense electrode (28) and the sense mass (42). The compensation and sense electrodes (24, 28) are coupled in reverse polarity so that the signal error component (78) substantially cancels the signal error component (76).