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Proceedings Paper

A tuning fork gyroscope with compensated imbalance signal
Author(s): E. Arnold; F. Nuscheler
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Paper Abstract

This paper is presenting a robust gyroscope sensor with an electrical and mechanical self-test option and the ability to suppress the quadrature error. The presented sensor is based on a tuning-fork working principle. The mechanical part is assembled in bulk-technology produced with a wet etching process. The two detection elements are manufactured with a standard CMOS-process and the material of the two thin-film actuators is AlN (aluminium-nitrid). The two actuators can be controlled independently from each other. Two electronic PCB's were developed for actuating and measurement. One is including the analogue signal path; the second PCB is the digital electronics consisting of a FPGA and other peripherals. The tuning fork is actuated in a primary oscillation mode also called drive mode. For keeping the oscillation in resonance, a digital PLL is used in a forced feedback loop. To have a constant energy in the drive mode an Amplitude-Gain-Control (AGC) is implemented. An appearing angular rate causes the corriolis-force which is actuating secondary oscillation, also called detection mode. The amplitude of this oscillation is proportional to the angular rate. The signal has a component resulting from the mechanical imbalance. To separate these two signal parts from each other a synchronous demodulator followed by a digital filter chain has been developed. To achieve the maximum suppression of the imbalance signal a control-loop is used to shift the phases of the two actuation signals. This creates an additional force that compensates the movement as a result of the mechanical imbalance. With the implementation of this control loop the performance of the sensor was increased. An enhanced temperature stability over operation was achieved with the means of this compensation.

Paper Details

Date Published: 17 May 2007
PDF: 6 pages
Proc. SPIE 6589, Smart Sensors, Actuators, and MEMS III, 65890I (17 May 2007); doi: 10.1117/12.724085
Show Author Affiliations
E. Arnold, EADS Deutschland GmbH (Germany)
F. Nuscheler, EADS Deutschland GmbH (Germany)

Published in SPIE Proceedings Vol. 6589:
Smart Sensors, Actuators, and MEMS III
Thomas Becker; Carles Cané; N. Scott Barker, Editor(s)

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