Hemispherical Resonator Gyroscope Mass Positioning
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Solution Overview
Problem
Hemispherical resonator gyroscopes face challenges in maintaining a long ring down time while adhering to a fixed size or micro-scale form factor, which is crucial for applications with size or power constraints.
Innovation Solution
The equivalent mass of the hemispherical resonator is increased by positioning heavy metals like tungsten, gold, or lead masses around the periphery, optimizing the ring down time without increasing the hemisphere diameter, and using pickoff electrodes to sense and control the vibration pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the hemisphere diameter is increased to increase the equivalent mass, then the ring down time is improved, but the form factor constraint is worsened
Solution Approach 1:
The patent applies local quality by positioning heavy metal masses (tungsten, gold, or lead) at specific locations around the periphery of the hemispherical resonator, specifically at points of maximum velocity or maximum deflection. This concentrates the mass increase in critical areas rather than uniformly increasing the entire hemisphere size, thereby extending ring down time while maintaining a compact 2 mm diameter form factor.
2Duration of action of moving object
If heavy metal masses are positioned around the periphery to increase equivalent mass, then the ring down time is improved, but the device complexity is worsened
Solution Approach 1:
The patent merges the mass positioning function with the existing resonator structure by integrating heavy metal masses directly onto the periphery of the hemispherical resonator. This combination approach eliminates the need for separate mass attachment mechanisms or additional structural components, thereby extending ring down time through increased equivalent mass while minimizing the increase in device 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
This approach extends the ring down time to at least 500 seconds in a 2 mm diameter gyroscope, enhancing its operational duration in power-constrained environments and maintaining a compact form factor suitable for various applications, including personal and military uses.
Implementation Method 1
A ring forcer electrode is configured to drive the hemispherical resonator. Voltage may be applied to the forcer electrode to control the amplitude of a standing wave associated with the resonator.
Implementation Method 2
The capacitance of the pickoff electrodes may be modulated at the resonator flexing frequency. The capacitance changes in the pickoff electrodes may then be used to determine rotation rates or rotation angles through the rotational-vibrational coupling (e.g., Coriolis coupling) between structural modes of the gyroscope.
Implementation Method 3
The capacitance changes in the pickoff electrodes may then be used to determine rotation rates or rotation angles through the rotational-vibrational coupling (e.g., Coriolis coupling) between structural modes of the gyroscope.
Implementation Method 4
The equivalent mass of the hemispherical resonator may be increased by positioning masses around the periphery of the hemispherical resonator. For example, a plurality of masses may be positioned around the periphery of the resonator outer rim.
Data Source
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AI summary
A micro-scale hemispherical resonator gyroscope includes a hemispherical resonator with a plurality of masses positioned around the periphery of the hemispherical resonator. At least some of the masses may be made of a heavy metal, such as tungsten, gold, platinum, or lead, and may be positioned at points of maximum deflection or velocity of the resonator. The hemispherical resonator may have a 2 mm diameter and a ring down time of at least 500 seconds.