Planar Angular Velocity Sensor Layout With Canceled Angular Momentum
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Solution Overview
Problem
Existing angular velocity sensors face issues due to non-zero total angular momentum, leading to instability, rate signal noise, and susceptibility to external mechanical shock and vibration, primarily caused by the combination of multiple moving masses.
Innovation Solution
A vibrating sensor element design where all motions occur in a single plane, minimizing total angular momentum by symmetrical arrangement of primary and Coriolis masses, using coupling levers and springs to ensure balanced and low-momentum operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple moving masses are combined in the sensor element, then the measurement capability is improved, but the total angular momentum becomes non-zero causing instability and noise
Solution Approach 1:
The patent applies the counterweight principle by positioning masses symmetrically around the rotation axis such that their angular momenta cancel each other out. The first and second masses are arranged to generate equal and opposite angular momentum components, resulting in near-zero total angular momentum while maintaining the measurement functionality of multiple masses
2Measurement precision
If multiple moving masses are combined in the sensor element, then the measurement capability is improved, but the susceptibility to external mechanical shock and vibration increases
Solution Approach 1:
The symmetric arrangement of masses with opposing angular momentum creates a balanced system that is less sensitive to external disturbances. When external mechanical shock or vibration occurs, the balanced mass configuration reduces the net impact on the measurement, thereby decreasing susceptibility to harmful external factors
3Adaptability or versatility
If motions occur in multiple directions, then the measurement functionality is enhanced, but the total angular momentum increases causing vibrational energy leakage
Solution Approach 1:
The patent configurations masses and spring structures to create opposing motion patterns that generate counterbalancing angular momentum. This allows the system to maintain versatile measurement functionality across different directions while the counteracting angular momentum prevents vibrational energy from leaking outside the sensor element
4Measurement precision
If non-zero total angular momentum exists, then the sensor can detect angular velocity, but the Q-value stability deteriorates
Solution Approach 1:
By arranging masses to produce equal and opposite angular momentum, the system achieves near-zero total angular momentum. This eliminates the source of vibrational energy leakage that would otherwise degrade the Q-value, thereby maintaining both angular velocity detection capability and Q-value stability
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 design achieves reliable angular velocity measurement with improved stability and reduced vibrational energy leakage, enhancing the Q-value of the sensor device by effectively canceling out total angular momentum.
Implementation Method 1
The two primary masses are suspended to the supporting body by a spring structure that enables a linear primary oscillation motion of the two primary masses
Implementation Method 2
Each of the two coupling lever structures is configured to relay an anti-phase primary motion of the two primary masses to a linear primary motion of the one coupled Coriolis mass
Implementation Method 3
The Coriolis masses are configured to be excited by the Coriolis force into first anti-phase linear secondary motions within the plane of the essentially planar sensor element
Data Source
Figure 1a
Figure 1b
Figure 2~3
AI summary
A sensor element for detecting angular velocity about a detection axis perpendicular to a plane of the sensor element is disclosed. The essentially planar sensor element comprises two primary masses and two Coriolis masses, and two sensing cells. The sensor element further comprises two coupling levers each coupled to the two primary masses by first springs and to one of the two Coriolis masses by second springs, the coupling levers enabling the two primary masses and the two Coriolis masses to be excited into a combined primary motion occurring in the plane of the essentially planar sensor element. In the combined primary motion, the direction of the angular momenta of linear primary oscillation motions of the primary masses and angular momenta of rotational primary motions of the coupling levers with respect to the geometrical centroid of the sensor element is opposite to the direction of the angular momenta of linear primary oscillation motions of the Coriolis masses with respect to the geometrical centroid of the sensor element.