Invensense, Inc.

Doruk Senkal

Joseph Seeger

Houri Johari-Galle

Robert Hennessy

Joe Seeger

Sriraman Dakshinamurthy

Carlo Pinna

Ali Shirvani

Ronak Chetan Desai

Robert Hennessey

A dynamically balanced 3-axis gyroscope architecture is provided. Various embodiments described herein can facilitate providing linear and angular momentum balanced 3-axis gyroscope architectures for better offset stability, vibration rejection, and lower part-to-part coupling.

Drive and sense balanced, semi-coupled 3-axis gyroscope

The subject disclosure provides exemplary 3-axis (e.g., GX, GY, and GZ) linear and angular momentum balanced vibratory rate gyroscope architectures with fully-coupled sense modes. Embodiments can employ balanced drive and/or balanced sense components to reduce induced vibrations and/or part to part coupling. Embodiments can comprise two inner frame gyroscopes for GY sense mode and an outer frame or saddle gyroscope for GX sense mode and drive system coupling, drive shuttles coupled to the two inner frame gyroscopes or outer frame gyroscope, and four GZ proof masses coupled to the inner frame gyroscopes for GZ sense mode. Components can be removed from an exemplary overall architecture to fabricate a single axis or two axis gyroscope and/or can be configured such that a number of proof-masses can be reduced in half from an exemplary overall architecture to fabricate a half-gyroscope. Other embodiments can employ a stress isolation frame to reduce package induced stress.

Drive and sense balanced, fully-coupled 3-axis gyroscope

In a first aspect, the angular rate sensor comprises a substrate and a rotating structure anchored to the substrate. The angular rate sensor also includes a drive mass anchored to the substrate and an element coupling the drive mass and the rotating structure. The angular rate sensor further includes an actuator for driving the drive mass into oscillation along a first axis in plane to the substrate and for driving the rotating structure into rotational oscillation around a second axis normal to the substrate; a first transducer to sense the motion of the rotating structure in response to a Coriolis force in a sense mode; and a second transducer to sense the motion of the sensor during a drive mode. In a second aspect the angular rate sensor comprises a substrate and two shear masses which are parallel to the substrate and anchored to the substrate via flexible elements. In further embodiments, a dynamically balanced 3-axis gyroscope architecture is provided. Various embodiments described herein can facilitate providing linear and angular momentum balanced 3-axis gyroscope architectures for better offset stability, vibration rejection, and lower part-to-part coupling.

A MEMS device may output a signal during operation that may include an in-phase component and a quadrature component. An external signal having a phase that corresponds to the quadrature component may be applied to the MEMS device, such that the MEMS device outputs a signal having a modified in-phase component and a modified quadrature component. A phase error for the MEMS device may be determined based on the modified in-phase component and the modified quadrature component.

Demodulation phase calibration using external input

Microelectromechanical systems (MEMS) gyroscopes and related measurement and calibration techniques are described. Various embodiments facilitate phase estimation of an ideal phase for a demodulator mixer associated with an exemplary MEMS gyroscope using quadrature tuning, which can improve offset performance over life time for exemplary MEMS gyroscopes. Exemplary embodiments can comprise adjusting a quadrature component of an exemplary MEMS gyroscope sense signal, measuring a change in offset of the exemplary MEMS gyroscope at an output of a demodulator mixer associated with the exemplary MEMS gyroscope, estimating a phase error between the quadrature component and a demodulation phase angle of the demodulator mixer based on the change in the offset, and periodically adjusting the demodulation phase angle of the demodulator mixer based on the phase error.

Microelectromechanical systems (MEMS) gyroscope calibration

A MEMS gyroscope includes a proof mass of a suspended spring mass system that is driven at a drive frequency. The proof mass moves relative to a sense electrode such that an overlap of the proof mass and sense electrode changes during the drive motion. A Coriolis force causes the proof mass to move relative to the sense electrode. The overlap and the movement due to the Coriolis force are sensed, and angular velocity is determined based on the magnitude of a signal generated due to a change in overlap and the Coriolis force.

On-chip gap measurement

A method includes receiving a signal from a sensor. The signal includes a first in-phase component and a first quadrature component. The first in-phase and quadrature components are identified. A rate signal is applied to the sensor and the sensor generates a sensed rate signal. A second in-phase and quadrature components associated with the sensed rate signal are determined. A phase error based on the first and the second in-phase components, and the first and the second quadrature components is determined. The method may further include reducing error in measurements associated with the sensor by dynamically compensating for the determined phase error, e.g., by modifying a clock signal, by changing a demodulation phase of a demodulator used to identify the in-phase and the quadrature components.

Growing community of inventors

San Jose, CA, United States of America

Doruk Senkal