Akustik dalga kılavuzu tabanlı dönüölçerler

We propose novel gyroscope architectures based on acoustic waves propagating in a waveguide. This thesis is composed of two parts. In the first part, the fundamentals of the proposed gyroscope are discussed. The new gyroscope will consist of a closed annular waveguide and a piezoelectric transducer, which excites the suitable acoustic modes of the waveguide. The piezoelectric transducer will generate two acoustic waves, which propagate in the opposite directions in the waveguide. When the waveguide is subjected to a rotational motion, due to the Coriolis forces, the acoustic waves that propagate in the opposite directions will gain different amounts of phases. The relative phase difference of these two waves will increase in proportional to the angular velocity of the waveguide. In other words, by measuring the phase difference between these two waves, one can monitor the rate of rotational motion. During our analysis of waveguides, we observed that the resonances of the waveguide structure shift. This is due to the upward and downward velocity shift of the counter-propagating waves in response to Coriolis force. Based on this observation, we performed in-depth analysis of vibrating gyroscope structures. This analysis constitutes the second part of the thesis. A typical vibrating gyroscope has two parts which are called drive and sense systems. Until now, the coupling between these two systems has been ignored and they have been analyzed separately. In the second part of this thesis, we demonstrate the analysis of the gyroscope including the coupling between drive and sense systems for the first time. Vibratory gyroscopes have attracted a lot of interest recently with the development of MEMS gyroscopes. These gyroscopes made their way through portable devices and smart phones. Novel gyroscope architectures have been proposed and analyzed in detail. However in most of these analyses, the coupling between the sense and drive systems were ignored. We analytically show that the drive and sense systems are coupled together via Coriolis force. As a result, resonances of the mechanical structure shift as the rotation rate increases for linear and torsional gyroscope systems. Starting from a simple gyroscope system, we calculated the sense and drive resonant frequency shifts in various configurations. Then, for more complex systems where analytical solution is difficult to obtain, we used commercially available FEM tools to determine the corresponding frequency shift. In general, we found that the shift is small and can be ignored for mode-matched linear vibratory gyroscopes, where Q of the sense system is less than 2500. But for higher Q systems, the frequency shift may affect the linearity of these gyroscopes. This sets a fundamental limit for the linearity of vibratory gyroscopes. Based on our calculations, the non-linearity is above 1% for linear 2-DOF mode-matched vibratory gyroscopes, where Q is above 3000 and for torsional 2-DOF mode-matched vibratory gyroscopes where Q is above 600. Multi-DOF and ring vibratory gyroscopes were also examined. We found that the effect is less pronounced for Multi-DOF gyroscopes.