Yaw-Rate Sensor with Segmented Rotation Elements
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Solution Overview
Problem
Conventional yaw-rate sensors are insensitive to angular accelerations and linear accelerations, making it difficult to differentiate between Coriolis force and angular acceleration about the x-axis, leading to interference issues.
Innovation Solution
A yaw-rate sensor design featuring a substrate with multiple rotation elements and coupling structures that allow for differential evaluation of detection signals, enabling the sensor to be insensitive to angular and linear accelerations by increasing frequency splitting between drive and detection modes, and using rocker structures and spring connections to enhance interference rejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional yaw-rate sensors with planarly oscillating masses are used, then the sensor can detect Coriolis force, but it cannot differentiate between Coriolis force and angular acceleration about the x-axis, leading to interference errors
Solution Approach 1:
The sensor is divided into multiple rotation elements (first and second rotation elements) that can be driven in opposite directions. Each rotation element generates signals that are differentially evaluated to separate Coriolis force from angular acceleration interference. The segmentation of the sensing function across multiple elements enables discrimination of different force types.
Solution Approach 2:
Different rotation elements are positioned and oriented to respond differently to Coriolis force versus angular acceleration. By creating local variations in the sensing elements' response characteristics, the system can distinguish between the two types of forces through comparative evaluation of their individual outputs.
2Measurement precision
If the sensor uses planarly oscillating masses subjected to Coriolis force, then it can measure yaw rate, but it remains sensitive to angular accelerations and linear accelerations which cause error signals
Solution Approach 1:
The sensor employs multiple rotation elements driven in opposite directions, with each element contributing to the overall measurement. The differential evaluation of signals from these segmented elements cancels out common-mode disturbances such as angular and linear accelerations while preserving the Coriolis force signal.
Solution Approach 2:
The rotation elements are driven in opposite directions, creating counterbalancing motions that cancel out the effects of angular and linear accelerations. This anti-weight approach ensures that interference forces affect both elements equally but in opposite senses, allowing them to be rejected through differential signal processing.
3Speed
If coupling elements with spring connections are added to connect rotation elements, then frequency splitting between drive and detection modes increases, but device complexity increases
Solution Approach 1:
The coupling elements with spring connections introduce an additional dimension of mechanical compliance to the system, enabling frequency splitting between drive and detection modes. By adding this elastic coupling dimension, the system achieves better mode separation despite the increased structural complexity.
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 sensor effectively differentiates between Coriolis force and angular/linear acceleration signals, reducing interference and achieving improved accuracy by shifting interference-sensitive modes to higher frequencies and compensating for quadrature errors.
Implementation Method 1
Micromechanical yaw-rate sensors for yaw rates about an axis which is parallel to the sensor plane (Z′ and yaw rate Qy) are normally designed as planarly oscillating masses or as masses performing rotational oscillations in the plane, which are subjected to a Coriolis force
Implementation Method 2
the coupling element is connected to the substrate via at least one spring
Data Source
AI summary
A yaw-rate sensor is described as having a substrate which has a main plane of extension for detecting a yaw rate about a first axis extending parallel to the main plane of extension is provided, the yaw-rate sensor having a first rotation element and a second rotation element, the first rotation element being drivable about a first axis of rotation, the second rotation element being drivable about a second axis of rotation, the first axis of rotation being situated perpendicularly to the main plane of extension, the second axis of rotation being situated perpendicularly to the main plane of extension, the first rotation element and the second rotation element being drivable in opposite directions.