Roman Forke

Yet another tuning fork gyroscope

This paper reports on the development of a micromechanical vibrating mass tuning fork gyroscope with coupled drive and sense modes. The mechanical structure has been designed to have a first anti-phase drive mode and a second anti-phase sense mode. The frequencies of all other modal modes are higher. The micromechanical structure is fabricated with a cavity SOI technology called BDRIE [1]. The analog ASIC for very low noise readout (<; 50 nV/rtHz) is placed on the MEMS and is connected symmetrically with wire bonds. MEMS and ASIC have been co-designed to best fit physically and electrically to each other.

Adjustable Force Coupled Sensor-Actuator System for Low Frequency Resonant Vibration Detection

The paper reports on a novel micro-electro-mechanical (MEM) sensor-actuator system for adjustable resonant vibration detection at frequencies below 1 kHz. The MEM system operates at standard pressure and utilizes the superheterodyne principle well known from information technologies. By mixing the low frequency vibration with a high frequency carrier, the information of the vibration is transformed into a higher frequency range. A resonant oscillator amplifies and filters the information.

A Tunable Resonant Vibration Measurement Unit Based on a Micromachined Force Coupled Sensor-Actuator System

In this paper we present a novel microsystem for frequency selective vibration measurements in a lower frequency range. It is based on a force coupled sensor-actuator system which transforms vibration signals from a low into a high frequency range and filters the desired spectral line by means of resonance amplification. Commonly, vibration signals are detected by wideband accelerometers and subsequent fast Fourier transformation. In contrast to electronic signal transformation from a time to a frequency domain, the presented approach performs most signal conditioning in the mechanical domain. Thanks to the high Q-factor of MEMS, the signal is amplified in a very narrow band with high signal-to-noise ratio. The sense frequency can be tuned by variation of the carrier frequency and motion signals are detected by capacitive pick-up. The sensor is fabricated by BDRIE (bonding & deep reactive ion etching) silicon technology.