Yaw Rate Sensor Mass Element Hollow Spherical Shell Design
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Solution Overview
Problem
Existing yaw rate sensors face challenges at high frequencies due to increased mechanical spring stiffness, reduced regenerative feedback and quadrature compensation capabilities, and the presence of spurious modes leading to false signals.
Innovation Solution
A yaw rate sensor design featuring a drive device connected to mass elements with a base layer and webs, allowing for antiparallel collinear drive motion and capacitively detecting changes in distance between mass elements and electrodes, which shifts the spurious mode spectrum to higher frequencies and enhances regenerative feedback and quadrature compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the operating frequency of the yaw rate sensor is increased to 15 kHz or higher, then the robustness against interfering vibrations is improved, but the mechanical spring stiffness increases and the regenerative feedback capability deteriorates
Solution Approach 1:
The patent changes the physical parameters of the detection mass by creating a hollow spherical structure instead of a solid mass. This modifies the mass distribution and moment of inertia while maintaining the overall mass, thereby altering the dynamic characteristics and spring stiffness to improve regenerative feedback capability at high operating frequencies
Solution Approach 2:
The detection mass is segmented into a hollow spherical shell structure rather than being a solid mass. This segmentation creates a shell with specific thickness and structural properties that differentiate the dynamic behavior, allowing improved regenerative feedback while maintaining high operating frequency robustness
2Speed
If the mass of the detection masses is reduced to maintain operating frequency, then the operating frequency is maintained, but the electrode surface areas are reduced and regenerative feedback capability deteriorates
Solution Approach 1:
The patent changes the geometric parameters of the detection mass by creating a hollow spherical shell with optimized thickness. This parameter change allows maintaining the mass for adequate electrode surface area while the hollow structure modifies the moment of inertia and spring stiffness to maintain high operating frequency and improve regenerative feedback capability
3Device complexity
If a solid material detection mass is used, then the structure is simple, but the spring stiffness increases and spurious modes appear at problematic frequencies
Solution Approach 1:
The detection mass is segmented into a hollow spherical shell structure, creating a thin-walled sphere geometry. This segmentation fundamentally changes the vibrational characteristics and spurious mode spectrum, moving harmful vibrations to less problematic frequency ranges while maintaining structural simplicity in manufacturing
Solution Approach 2:
The patent employs a shell structure that can be viewed as a composite geometry combining the spherical base form with a controlled thickness layer. This composite structural approach allows tuning of mechanical properties to suppress spurious modes while maintaining manufacturing simplicity
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 effectively suppresses spurious modes at high frequencies, improves regenerative feedback and quadrature compensation capabilities, and reduces mass and spring stiffness, leading to more robust and accurate yaw rate measurements.
Implementation Method 1
When the detection mass or the detection masses is/are then excited to a vibration parallel to the substrate plane with the aid of a drive, a rotation about an axis which is in the substrate plane and is situated orthogonally with respect to the vibration direction of the detection masses, results in a deflection of the detection masses perpendicular to the substrate plane due to the Coriolis force
Implementation Method 2
Consequently, the distance between the electrodes and the detection masses also changes. In this regard, the corresponding capacitance also changes. This change may be detected and converted into an appropriate yaw rate of the rotary motion of the body
Data Source
AI summary
A yaw rate sensor includes a drive device, at least one mass element which is connected to the drive device, and at least one detection electrode for detecting a motion of the mass element. The mass element has a base layer and at least one web which is situated on the base layer. Also, a method for manufacturing a mass element.