Structural design and experimental characterization of torsional micromachined gyroscopes with non-resonant drive mode

Abstract

This paper reports a novel gimbal-type torsional micromachined gyroscope with a non-resonant actuation scheme. The design concept is based on employing a 2 degrees-of-freedom (2-DOF) drive-mode oscillator comprising a sensing plate suspended inside two gimbals. By utilizing dynamic amplification of torsional oscillations in the drive mode instead of resonance, large oscillation amplitudes of the sensing element are achieved with small actuation amplitudes, providing improved linearity and stability despite parallel-plate actuation. The device operates at resonance in the sense direction for improved sensitivity, while the drive direction amplitude is inherently constant within the same frequency band. Thus, the necessity to match drive and sense resonance modes is eliminated, leading to improved robustness against structural and thermal parameter fluctuations. In the paper, the structure, operation principle and a MEMS implementation of the design concept are presented. Detailed analysis of the mechanics and dynamics of the torsional system is covered, and the preliminary experimental results verifying the basic operational principles of the design concept are reported.

Towards a biomimetic gyroscope inspired by the fly's haltere using microelectromechanical systems technology

“…Hence, besides the responsivity of the sensor, the noise level of the system determines the fundamental detection threshold of the system. To find the detection threshold of our system, we assume a power spectral density Maenaka et al [28] Tang et al [29] Nalbach [23] Li et al [30] Luo et al [31] Xie and Fedder [13] Acar and Shkel [32] Alper and Akin [14] Zaman et al [33] Degawa et al [34] Trusov et al [15] Prikhodko et al [39] Yan et al [35] Walther et al [36] Droogendijk et al [37] this work Figure 3. given by Johnson -Nyquist (thermal) white noise [40]:…”

“…Although we reported on the design and fabrication of such a gyroscope earlier [37], we implemented some important design adjustments here. The suspension of the haltere-based gyroscope is changed to a gimbal-suspension, such as the gyroscope described by Acar & Shkel [32]. In doing so, the effects of residual stress by having a bilayer suspension (i.e.…”

Control of MEMS Vibration Modes With Pulsed Digital Oscillators: Part I—Theory

“…For instance, parametric resonance amplification is an example of an efficient technique [9]- [12] that allows the excitation of the same mechanical structure at a higher frequency to improve sensitivity. In gravimetric sensors, the use of higher order modes generally serves to increase the sensitivity to mass changes, whereas it is desired in gyroscopes to avoid the activation of certain resonant modes of the inertial mass [13]. Moreover, the activation of higher vibration modes to increase performance has been also reported in atomic force microscopes [14], [15] and in piezoelectric sensors and actuators [16], where electrodes have been specifically designed to activate certain modes.…”

Control of MEMS Vibration Modes With Pulsed Digital Oscillators—Part II: Simulation and Experimental Results

“…However, permission to use this material for any other purposes must be obtained from the IEEE by sending an email to pubs-permissions@ieee.org. the inertial mass [11], [12].…”