Session: VIB-01/MSNDC-08-03

Paper Number: 148509

148509 - Optimization of Hemispherical Resonators (Hrs) for Hemispherical Resonator Gyroscope (Hrg) Applications 

The functionality of a vibratory gyroscope is primarily governed by the dominant flexural mode (DFM), which is often referred to as the “wine glass mode” owing to its high sensitivity to external sinusoidal excitation. These modes are referred to as ‘degenerate’ mode shapes, where an angle of 45 degrees separates the primary and the secondary modes. In vibratory gyroscope applications, the primary mode is steadily excited via resonance while the resonator resides inside the gyroscope, which is attached to a rotating body in free space. This research presents the objectives behind the optimization process developed for designing a resonator employed in a Hemispherical Resonator Gyroscope (HRG). The resonator is the heart of the gyroscope, and persistent sinusoidal excitation precisely at Dominant Flexural Frequency (DFF) is essential for the operation of the HRG. Hence, the design optimization process to obtain a prescribed frequency separation around the DFF is critical in the resonator design. Methodologies for achieving targeted frequency separation between the Dominant Flexural Frequency (DFF) and adjacent frequencies have been demonstrated for HR structures in the ANSYS DM/DX (Design Modeler/Design Xplorer) computational environment. The developed optimization methodology has been shown to be robust and was able to work in the presence order shifting of natural frequencies. In general, MO optimization method resulted in favorable frequency separation for the HR. It was demonstrated that targeted separation could still be attained while minimizing the total material required for manufacture. When a wider range was considered, the IPs had a broader design space, which allowed the software to reach a larger set of potential solutions. This led to uncovering hidden relationships between IPs and objectives, which subsequently led to better results. Methodologies for achieving targeted frequency separation between the Dominant Flexural Frequency (DFF) and adjacent frequencies have been demonstrated for HR structures

 

Presenting Author: Samuel Asokanthan The University of Western Ontario

Presenting Author Biography: Professor Asokanthan's research interests are in the areas of Dynamic Systems and Control as applied, in particular, to Flexible Structures and Rotating and Axially Moving Flexible Multi-body Systems. Specific applications cover a range of Mechanical, Aerospace and Biological Systems.

Prior to joining the University of Western Ontario in January 2002, Professor Asokanthan held a faculty position in the Department of Mechanical Engineering at the University of Queensland, Brisbane, Australia. He also gained industrial research and development experience in the area of Inertial Stabilization and Control, working as a NSERC industrial postdoctoral research fellow in Canada after completion of his PhD at the University of Waterloo.

Authors:

Yoshika Alahakoon The University of Western Ontario
Samuel Asokanthan The University of Western Ontario
O. Remus Tutunea-Fatan The University of Western Ontario