Coriolis Vibratory Accelerometer Flexure Gimbal Control
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Solution Overview
Problem
Traditional electromagnetic and electrostatic force-rebalance instruments, such as accelerometers, face instability and non-repeatability issues due to characteristics of control electronics, which affect the accuracy of rotation or acceleration measurements.
Innovation Solution
A Coriolis Vibratory Accelerometer (CVA) system that includes a pendulous element rotating via flexures in response to input acceleration, with a torque-summing gimbal and oscillating-masses driven by a triangular wave forcer signal, generating Coriolis force-rebalance through synchronized oscillatory motion, allowing the accelerometer controller to determine input acceleration based on the rotation of the gimbal and oscillating-masses' velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional electromagnetic and electrostatic force-rebalance control electronics are used, then the accelerometer can provide rotation or acceleration measurement, but instability and non-repeatability of control electronics characteristics cause measurement errors
Solution Approach 1:
The patent replaces traditional electromagnetic and electrostatic force-rebalance control electronics with a mechanical Coriolis vibratory system. The accelerometer uses a vibrating proof mass where Coriolis forces directly indicate acceleration, eliminating the need for unstable control electronics while maintaining measurement capability.
Solution Approach 2:
The patent employs mechanical vibration of a proof mass at a resonant frequency to create a stable measurement reference. The Coriolis force acts on the vibrating mass proportionally to the applied acceleration, providing a stable and repeatable measurement mechanism that does not depend on control electronics characteristics.
2Reliability
If Pendulous Integrating Gyroscope Accelerometer (PIGA) with gyroscopic precession is used, then control electronics instability is avoided, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates the complex gyroscopic precession mechanism from the PIGA design. Instead, it uses a simpler Coriolis vibratory system where a proof mass vibrates linearly and the Coriolis force directly provides the measurement signal, removing unnecessary mechanical complexity while maintaining reliability.
Solution Approach 2:
The patent inverts the traditional approach by using linear vibration instead of rotational gyroscopic precession. The Coriolis force acts perpendicular to both the vibration direction and the applied acceleration, providing a more direct and simpler measurement path compared to the indirect gyroscopic precession method.
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
The CVA system provides accurate and reliable measurement of input acceleration by mitigating electronic control errors, offering improved reliability and accuracy compared to traditional accelerometers like the Pendulous Integrating Gyroscope Accelerometer (PIGA) through Coriolis force-rebalance and optical velocity detection.
Implementation Method 1
the in-plane oscillatory motion of the plurality of oscillating-masses and the rotation of the torque-summing gimbal in the oscillatory manner generates a Coriolis force to provide Coriolis force-rebalance of the pendulous element
Implementation Method 2
a pendulous element that rotates about a first axis via first flexures in response to an input acceleration provided along a second axis
Implementation Method 3
the accelerometer controller is configured to determine the input acceleration based on the rotation of the torque-summing gimbal
Data Source
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AI summary
A CVA system includes a sensor system including a pendulous element that rotates about a first axis via first flexures in response to an input acceleration provided along a second axis that is orthogonal with respect to the first axis. A torque-summing gimbal is coupled to the pendulous element via the first flexures and coupled to a housing via second flexures. The system further includes an accelerometer controller that monitors a pickoff signal of the rotation of the pendulous element from a first electrode coupled to the pendulous element and to provide a forcer signal to at least one second electrode coupled to the torque-summing gimbal to force the torque-summing gimbal to rotate about the second axis via the second flexures based on the pickoff signal to provide Coriolis force-rebalance of the pendulous element. The accelerometer controller can determine the input acceleration based on the rotation of the torque-summing gimbal.