Three-axis Rotation Rate Sensor with Dual Rotor
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Solution Overview
Problem
Conventional three-axis rotation rate sensors are complex, sensitive to external vibrations and electrical measuring pulses, and require additional elements for Z-direction measurement, making them less robust and more susceptible to interference.
Innovation Solution
A compact three-axis rotation rate sensor design featuring dual-function rotors with deflectable seismic masses, where Coriolis forces induce radial displacement detectable via phase-opposed drive and detection movements, minimizing additional elements and coupling structures, thus reducing spurious modes and interference sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional elements and coupling structures are added to enable Z-direction measurement, then three-axis measurement capability is achieved, but device complexity and susceptibility to interference increase
Solution Approach 1:
The rotor structure is designed to serve multiple functions: it provides X-Y plane rotation rate measurement through conventional Coriolis mass movement, and simultaneously enables Z-axis rotation rate measurement through radial elongation/compression forces. The same rotor and spring elements are used for both measurement directions, eliminating the need for separate Z-axis sensing structures.
Solution Approach 2:
The patent combines the Z-axis measurement functionality with the existing X-Y measurement structure by integrating radial force sensing into the rotor-spring system. The spring elements that support the rotor for X-Y measurement also detect radial elongation/compression for Z-axis measurement, merging two measurement functions into a unified structure.
2Adaptability or versatility
If additional elements and coupling structures are added for Z-direction measurement, then three-axis measurement capability is achieved, but susceptibility to external vibrations and electrical measuring pulses increases
Solution Approach 1:
The rotor structure is designed to serve multiple functions: it provides X-Y plane rotation rate measurement through conventional Coriolis mass movement, and simultaneously enables Z-axis rotation rate measurement through radial elongation/compression forces. The same rotor and spring elements are used for both measurement directions, eliminating the need for separate Z-axis sensing structures.
Solution Approach 2:
The patent converts the previously harmful radial forces (which were ignored or caused interference) into useful measurement signals for Z-axis detection. By equipotentializing the support structure and using the spring elements as both support and sensing mechanisms, the radial forces become the basis for Z-axis measurement rather than interference.
3Adaptability or versatility
If soft spring elements are used in complex coupling structures, then three-axis measurement capability is achieved, but sensitivity to external vibrations increases
Solution Approach 1:
The patent extracts the Z-axis measurement function from the concept of adding separate soft coupling structures and instead integrates it into the existing rigid rotor and spring element system. By removing the need for additional soft coupling elements and using the existing springs for both support and Z-axis sensing, the design eliminates the vibration sensitivity associated with multiple soft elements.
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 achieves robustness against vibrations, low energy decoupling, and high sensitivity with improved surface area utilization, reducing manufacturing variations and frequency distribution, resulting in a more precise and less sensitive device.
Implementation Method 1
When an external rotation whose rotational axis is directed in parallel to the XY plane is applied to the sensor, Coriolis forces act on the rotors and tilt the rotors relative to the plane
Implementation Method 2
the radially extending Coriolis forces effectuate a displacement of the seismic masses in the radial direction of the rotor, which may be correspondingly detected
Implementation Method 3
This deflection may in turn be determined via a change in capacitance with respect to stationary detection electrodes
Data Source
AI summary
A three-axis rotation rate sensor including a substrate and a double rotor. The double rotor includes a first rotor and a second rotor which are elastically connected to one another via a first coupling element so that the two rotors are excitable to rotary oscillations in phase opposition. The first rotor includes a first seismic mass and a second seismic mass that are deflectably supported with respect to the first rotor, and the second rotor includes a third seismic mass and a fourth seismic mass that are deflectably supported with respect to the second rotor. The first mass is connected to the third mass via a first rocker element so that upon a lateral deflection of the first mass, the third mass is deflected in a direction opposite the lateral deflection of the first mass.