Yaw Rate Sensor Out-of-Plane Coriolis Detection
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Solution Overview
Problem
Existing yaw rate sensors are not effectively designed to detect Coriolis forces perpendicular to the substrate surface, leading to interference from circular acceleration and reduced sensitivity, especially when integrated into vehicles for space-saving and high-frequency applications.
Innovation Solution
The design incorporates multiple drive and detection mass elements connected by springs to suppress vibrations and ensure that Coriolis forces are transmitted only to detection mass elements, with a symmetrical arrangement of centers of gravity to prevent measurement corruption, enhancing sensitivity and reducing interference from accelerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single drive mass element and detection mass element are used with Coriolis force transmission along the surface, then the sensor can detect rotation about an axis perpendicular to the substrate, but the sensor dimensions become large and integration into vehicles becomes difficult
Solution Approach 1:
The patent changes the orientation of the Coriolis force transmission from in-plane (along the substrate surface) to out-of-plane (perpendicular to the substrate surface). The detection mass element is deflected along a second axis extending perpendicular to the substrate surface, allowing the Coriolis force to be transmitted through the substrate thickness rather than across the surface. This dimensional change enables compact sensor dimensions while maintaining detection capability.
2Measurement precision
If the detection mass element is deflected along the surface, then the Coriolis force can be detected, but circular acceleration interferes with the measurement
Solution Approach 1:
The patent creates an asymmetric configuration where the drive mass element and detection mass element are positioned such that their centers of gravity do not coincide. The detection mass element is offset from the drive mass element along the first axis, creating an asymmetric mass distribution. This asymmetry ensures that circular acceleration produces unequal effects on the detection mass element, allowing the sensor to distinguish between Coriolis force and circular acceleration interference.
Solution Approach 2:
The substrate acts as an intermediary element that transmits the Coriolis force from the drive mass element to the detection mass element perpendicular to the surface. By using the substrate as the transmission medium rather than direct in-plane connection, the sensor isolates the detection path from circular acceleration effects that would otherwise interfere with measurements.
3Measurement precision
If the sensor is designed for high working frequencies, then the influence of interfering accelerations is reduced, but the complexity of the drive and detection systems increases
Solution Approach 1:
The patent segments the sensor into distinct functional elements: a drive mass element for generating vibrations, a detection mass element for sensing Coriolis force, and corresponding drive and detection devices. This segmentation allows each element to be optimized independently for high-frequency operation while maintaining clear functional separation that reduces interference between components.
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 configuration results in a highly sensitive yaw rate sensor that effectively detects Coriolis forces perpendicular to the substrate, reducing interference from circular acceleration and improving transverse sensitivity, allowing for integration into vehicles and high-frequency operations.
Implementation Method 1
a detection mass element deflectable along a second axis extending perpendicular to the first axis under the influence of a Coriolis force
Implementation Method 2
a drive mass element situated above a surface of a substrate and drivable to vibrate by a drive device along a first axis extending parallel to the surface
Implementation Method 3
The Coriolis force is transmitted by springs from the drive mass element to the detection mass element
Data Source
AI summary
A yaw rate sensor includes a drive mass element which is situated above a surface of a substrate and is drivable to vibrate by a drive device along a first axis extending along the surface, having a detection mass element, which is deflectable under the influence of a Coriolis force along a second axis perpendicular to the surface, and having a detection device by which the deflection of the detection mass element along the second axis is detectable. Due to the arrangement of the second axis perpendicular to the surface, the yaw rate sensor may be integrated into a chip together with additional yaw rate sensors suitable for detection of rotations about axes of rotation in other directions.