Loss mechanisms in metallic hemispherical resonators and cost-effective gyroscope applications

Date

2025-6-24

Author

Yavuz, Ahmet Faruk

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Hemispherical resonator gyroscopes (HRG) offer outstanding performance with ultra-low noise with strong resistance to environmental fluctuations. Their ability to operate in both rate and rate-integrating modes, and to transition between these modes on demand, makes them attractive for a wide range of navigation and stabilization applications. Conventional HRGs, however, rely on fused-quartz resonators that demand extremely precise and costly machining, limiting their adoption in emerging, cost-sensitive platforms. This thesis addresses that limitation by investigating cost-effective HRG designs based on metallic resonator shells. The research begins with an in-depth analysis of the loss mechanisms that limit performance and long-term stability, establishing a theoretical framework for predicting performance. Using these insights, to determine the resonator material for compact prototype, hemispherical shells were fabricated from both aluminium and Super Invar and subjected to an iterative characterization tests. Temperature-dependent resonance frequency, mechanical quality factor, and closed-loop gyroscopic rate response were obtained and compared. The systematic evaluation showed that the aluminium resonator outperformed its Super Invar counterpart across all key metrics, leading to its selection for the compact prototype. The resulting cost-effective aluminum HRG prototype achieved an angular random walk of 3.39x10^(-3) °/√h and a bias instability of 3.35x10^(-2 )°/h, confirming that, although a metallic HRG does not quite reach the extraordinary performance levels of quartz, it can still achieve navigation-grade accuracy at a fraction of the cost of traditional quartz sensors, thereby ability to broadening the practical application space for HRG technology.

Subject Keywords

Gyroscope, Hemispherical resonator, Metallic resonator, Coriolis vibratory gyroscope, Quality factor, Thermoelastic dissipation

URI

https://hdl.handle.net/11511/115436

Collections

Graduate School of Natural and Applied Sciences, Thesis