Hemispherical Gyroscope Stem Nesting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-accuracy Coriolis vibratory gyroscopes with axisymmetrical resonators of cylindrical or hemispherical shape face challenges in reducing size without compromising accuracy, as minimizing the resonator size decreases the quality factor and increases costs and complexity due to numerous metallic sealed leads.
Innovation Solution
The design incorporates holes in the bottom of the resonator and a stem inside the resonator to minimize dimensions, using piezoceramic electrodes and sealed leads to maintain accuracy and reduce size, allowing for compact high-accuracy gyroscopes with a cylindrical or hemispherical configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the resonator size is minimized to reduce gyroscope dimensions, then the overall size is reduced, but the quality factor decreases and accuracy is compromised
Solution Approach 1:
The patent repositions the stem from an external attachment to an internal structure within the resonator cavity. This dimensional reconfiguration allows the stem to occupy internal space rather than external space, enabling the resonator outer dimensions to be reduced while maintaining the stem length and resonator inner dimensions necessary for high quality factor operation.
Solution Approach 2:
The stem is nested inside the resonator cavity, with the resonator wall forming the external housing. This nesting arrangement eliminates the need for external mounting structures and reduces the overall gyroscope envelope dimensions while preserving the functional resonator dimensions. The resonator itself becomes the external housing, integrating multiple functions into a compact structure.
2Strength
If traditional external stem mounting is used, then structural support is provided, but the overall gyroscope dimensions increase
Solution Approach 1:
The resonator wall and external housing are merged into a single integrated structure. The resonator shell serves dual functions as both the vibrating element and the external protective housing, eliminating the need for separate mounting brackets, external stems, and additional structural components. This merging reduces the number of parts and minimizes the overall gyroscope volume.
Solution Approach 2:
The stem is repositioned from an external radial attachment to an internal axial structure within the resonator cavity. This dimensional change allows the support structure to be contained within the resonator's internal volume rather than extending outward, reducing the gyroscope's external dimensions while maintaining structural integrity through the resonator wall itself.
3Reliability
If numerous metallic sealed leads are used for electrode connections, then electrical connectivity is achieved, but costs and manufacturing complexity increase
Solution Approach 1:
The piezoceramic material is extracted from traditional discrete electrode configurations and integrated directly into the resonator wall structure. This extraction eliminates the need for separate electrode assemblies and their associated multiple sealed leads, reducing manufacturing complexity while maintaining reliable electrical connections through the piezoelectric material's inherent properties.
Solution Approach 2:
The piezoceramic material performs multiple functions simultaneously: it provides structural reinforcement to the resonator wall, enables piezoelectric actuation for vibration excitation, and provides capacitive sensing for detection. This multi-functionality eliminates the need for separate structural, actuation, and sensing components, thereby reducing the number of sealed leads and interconnections required.
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 approach enables the reduction of overall gyroscope dimensions while maintaining high accuracy and reducing costs by minimizing the number of metallic sealed leads, achieving dimensions comparable to MEMS gyroscopes without decreasing the quality factor.
Implementation Method 1
piezoceramic electrodes and sealed leads to maintain accuracy and reduce size
Implementation Method 2
Rotation about the input axis of the vibrating structure creates Coriolis forces: F c =2m[Ω×V], where F c is the Coriolis force vector, m is the modal mass of the resonator, Ω is the vector of the angular velocity with respect to the input axis of the resonator, and V is the vector of the linear velocity of the elements of the structure (during vibration)
Implementation Method 3
it is best to excite the elastic wave according to the second mode of resonator vibrations with specified amplitude, which is stabilized by a system for automatic gain control (AGC). This standing wave has four antinodes and nodes of the vibrations, where the amplitude of the vibrations is maximum and minimum, respectively
Data Source
Figure 1
Figure 2~4
AI summary
A Coriolis vibratory gyroscope, characterized in that it comprises a thin-walled resonator of hemispherical (9) or cylindrical (1) or toroidal (10) shape, fastened centrally on a stem (2) located within the resonator holes (12) being made in a wall of the resonator, the holes being arranged around said stem, the number of holes being determined from the formula "4nk", where "k" is an integer, "n" is the order of vibration modes of the thin walled resonator, and the angle between each adjacent hole is equal to "n/2nk", wherein, said stem is rotationally symmetric about its longitudinal axis and is fastened on a base (3), electrodes (14) are arranged on the resonator wall or alongside it for excitation and measurement of two vibration modes, with leads passing from the electrodes through holes in the resonator wall,the base is made with a seating (4) for the resonator stem, and leads pass through the base to outside of the base, the leads being electrically-insulated and sealed relative to the base, and being configured for lead-in and/or lead-out of signals through the base, thereby allowing the signals to pass from outside the base, through the base, through the holes in the resonator wall and to the electrodes.