Inertial Sensor Z-Axis Actuation for Angle Detection Accuracy
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Solution Overview
Problem
Current inertial sensors for autonomous driving systems face accuracy issues in whole angle mode due to errors in vibration direction, time delays, and drive gain differences between drive axes, which affect the precision of angle detection.
Innovation Solution
An inertial sensor configuration that includes a resonator with a first and second drive mode, a mounting board with electrode portions, and an actuator that vibrates in the z-axis direction to excite the resonator, maintaining resonance without hindering rotational direction, thereby reducing errors and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inertial sensors use planar electrode arrangements to drive the resonator, then the structure is simple, but errors in vibration direction and drive gain differences occur, reducing angle detection accuracy
Solution Approach 1:
The patent transitions from planar (2D) electrode arrangements to a three-dimensional configuration where electrode portions are arranged around the resonator in the z-axis direction. This dimensional change allows the actuator to vibrate in the z-axis direction, exciting the resonator without introducing errors in the vibration direction or drive gain differences that plague conventional planar configurations. The electrode portions are positioned at distances from the resonator surface, creating a three-dimensional electrostatic actuation field that maintains precise vibration control.
2Stability of the object's composition
If the actuator vibrates in the z-axis direction to excite the resonator, then vibration amplitude consistency is improved, but the device structure becomes more complex
Solution Approach 1:
The mounting board is segmented into multiple electrode portions arranged around the resonator at different distances. This segmentation allows each electrode portion to contribute independently to the z-axis vibration excitation, enabling precise control of the resonator's vibration amplitude. The segmented electrode arrangement creates multiple electrostatic actuation zones that work together to maintain consistent vibration amplitude without requiring a monolithic complex actuator structure.
3Measurement precision
If electrode portions are arranged around the resonator at distances, then quadrature errors are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the geometric parameters of the electrode arrangement by positioning electrode portions at specific distances from the resonator surface and arranging them around the resonator perimeter. This parameter optimization creates an electrostatic field distribution that excites the resonator in the z-axis direction with minimal quadrature errors. The specific spacing and arrangement parameters are designed to balance manufacturing feasibility with high measurement precision, reducing sensitivity to minor positioning variations.
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 proposed configuration enhances the accuracy of angle detection in whole angle mode by minimizing the influence of errors and maintaining consistent vibration amplitude, reducing quadrature errors and phase differences, and improving overall detection precision.
Implementation Method 1
The actuator is configured to vibrate in a z-axis direction... the actuator is further configured to vibrate the resonator in the z-axis direction to cause a resonance mode
Implementation Method 2
The actuator is configured to vibrate in a z-axis direction... vibrate the resonator in the z-axis direction
Data Source
AI summary
An inertial sensor includes a resonator, a mounting board, and an actuator. The resonator has a first drive mode and a second drive mode. The mounting board has a plurality of electrode portions arranged at a distance from each other and surrounding the resonator. The actuator is configured to vibrate in a z-axis direction. The z-axis direction is a direction orthogonal to a planar direction of the mounting board. The actuator is further configured to vibrate the resonator in the z-axis direction to cause a resonance mode.