US 2026/0118138 A1Published application

Scale factor calibration method for microelectromechanical gyroscopes

AssigneeSTMicroelectronics International N.V.

InventorsLuca GUERINONI, Davide BERNABUCCI, Gianfranco Javier YALLICO SANCHEZ, Matteo QUARTIROLI

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Abstract

A microelectromechanical gyroscope includes a movable mass, a movable sensing electrode of the movable mass, a fixed sensing electrode capacitively coupled to the movable sensing electrode, and a bias terminal of the movable mass. A calibration method includes: applying a sequence of forcing signals to the bias terminal having a forcing time and that are determined by time variable signals superimposed on respective forcing bias voltages selected in a range; acquiring a sequence of sense signals indicative of a damped oscillation of the movable mass along a sense direction caused by respective forcing signals consecutively to respective forcing times; estimating from the sense signals a sequence of respective natural sense frequencies, each dependent on the corresponding forcing bias voltage; and estimating a sense gap from the sequence of natural sense frequencies that is indicative of a distance at rest between the movable sensing electrode and the fixed sensing electrode.

Claims17

Dependent claims

A method for calibrating a microelectromechanical gyroscope that includes a movable mass, a movable sensing electrode of the movable mass, a fixed sensing electrode capacitively coupled to the movable sensing electrode of the movable mass, and a bias terminal of the movable mass, the method including:

performing a first calibration procedure comprising:
applying, to the bias terminal of the movable mass, a sequence of forcing signals, wherein each forcing signal has a forcing time and is determined by a signal that is variable over time superimposed on a respective forcing bias voltage selected in a range of forcing bias voltages;
acquiring a sequence of sense signals, wherein each sense signal is indicative of a damped oscillation of the movable mass along a sense direction caused by a respective one of the forcing signals consecutively to the respective forcing time;
from the sequence of sense signals, estimating a sequence of respective natural sense frequencies, each dependent on the forcing bias voltage of the corresponding forcing signal;
and
estimating from the sequence of natural sense frequencies a reference sense gap indicative of a distance at rest between the movable sensing electrode of the movable mass and the fixed sensing electrode.

3 more elements

A system for sensing angular velocity, comprising:

a microelectromechanical gyroscope;
and
an electronic processing unit coupled to the gyroscope,
wherein the microelectromechanical gyroscope comprises:
a movable mass;
a movable sensing electrode of the movable mass;
a fixed sensing electrode, capacitively coupled to the movable sensing electrode of the movable mass;
and
a bias terminal of the movable mass;
and
wherein the electronic processing unit comprises:
a signal generator configured to apply to the bias terminal of the movable mass a sequence of forcing signals, wherein each forcing signal has a forcing time and is determined by a signal that is variable over time superimposed on a respective forcing bias voltage selected in a range of forcing bias voltages;
an analog-to-digital converter configured to acquire a sequence of sense signals, wherein each sense signal is indicative of a damped oscillation of the movable mass along a sense direction caused by a respective one of the forcing signals consecutively to the respective forcing time;
a sampler configured to estimate a sequence of respective natural sense frequencies from the sense signals, wherein each natural sense frequency is dependent on the forcing bias voltage of the corresponding forcing signal;
and
an estimator configured to estimate from the sequence of natural sense frequencies a sense gap indicative of a distance at rest between the movable sensing electrode of the movable mass and the fixed sensing electrode.

13 more elements

Dependencies are inferred from the claim text.